Guidelines for Facility Siting and Layout

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GUIDELINES FOR

FACILITY SITING AND LAYOUT

Center for Chemical Process Safety of the

American Institute of Chemical Engineers 3 Park Avenue, New York, New York 10016-5991

Copyright © 2003 American Institute of Chemical Enginers 3 Park Avenue New York, New York 10016-5991 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise without the prior permission of the copyright owner. AIChE™and CCPS® are trademarks owned by the American Institute of Chemical Engineers. These trademarks may not be used without the prior express written consent of the American Institute of Chemical Engineers. The use of this product in whole or in part for commercial use is prohibited without prior express written consent of the American Institute of Chemical Engineers. To obtain appropriate license and permission for such use contact Scott Berger, 212-591-7237, [email protected]. CCPS Publication Number G-84 Library of Congress Cataloging-in-Publication Data: Library of Congress Data Applied for ISBN 0-8169--0899-0 It is sincerely hoped that the information presented in this volume will lead to an even more impressive safety record for the entire industry. However, the American Institute of Chemical Engineers, its consultants, CCPS Subcommittee members, their employers, and their employers’ officers and directors and Baker Engineering and Risk Consultants Cheryl A. Grounds and Joseph R. Natale disclaim making or giving any warranties or representations, express or implied, including with respect to fitness, intended purpose, use or merchantability, and/or correctness or accuracy of the content of the information presented in this document. As between (1) American Institute of Chemical Engineers, its consultants, CCPS Subcommittee members, their employers, and their employers’ officers and directors and Baker Engineering and Risk Consultants Cheryl A. Grounds and Joseph R. Natale (2) the user of this document accepts any legal liability or responsibility whatsoever for the consequences of its use or misuse.

This book is available at a special discount when ordered in bulk quantities. For information, contact the Center for Chemical Process Safety at the address shown above. PRINTED IN THE UNITED STATES OF AMERICA 10 9 8 7 6 5 4 3 2 1

Contents

Preface

ix

Acknowledgments

xi

1 INTRODUCTION

1.1. Objectives

1

1.2. How To Use This Book

2

1.3. Layers of Safety

4

1.4. References

6

2 MANAGEMENT OVERVIEW

2.1. Implications of Siting and Layout

7

2.2. Management of Risks

8

2.3. Basis for Facility Siting and Layout

8

2.4. Changing World

10

3 PREPARING FOR THE SITE SELECTION PROCESS

3.1. Project Description

14

3.2. Assembling a Site Selection Team

16

3.3. Preliminary Site Size Determination

19

3.4. Preliminary Hazard Screening

20

3.5. Guidelines for the Survey and Data Collection Effort

26

3.6. Environmental Control Issues

29 v

vi

Contents

4 SITE SURVEY AND SELECTION

4.1. 4.2. 4.3. 4.4. 4.5. 4.6. 4.7. 4.8.

Information Required to Select a Site Transportation Issues Utilities Electrical and Communications Systems Environmental Controls Fire, Safety, and Security Site Features Multi-Chapter Example

33 39 44 47 49 51 53 55

5 SITE AND PLANT LAYOUT

5.1. General 5.2. The Site 5.3. Block Layout Methodology 5.4. Spacing Tables 5.5. Utilities 5.6. Electrical and Control Facilities 5.7. Process 5.8. Outside Battery Limits (OSBL) 5.9. Tank Storage 5.10. Occupied and Critical Structures 5.11. Multi-Chapter Example

64 66 71 72 74 80 82 85 92 94 97

6 EQUIPMENT LAYOUT AND SPACING

6.1. 6.2. 6.3. 6.4. 6.5.

Spacing Tables General Single- and Multilevel Structures Enclosed Process Units Layout and Spacing to Minimize Vapor Cloud Explosion Effects

101 103 104 105 105

vii

Contents

6.6. 6.7. 6.8. 6.9.

Relative Location of Equipment Equipment with Air Intakes Equipment-to-Equipment Separation Distances Multi-Chapter Example

106 107 108 116

7 OPTIMIZE THE LAYOUT

7.1. Layout Method Review 7.2. Layout Issues Resolution 7.3. The Right Answer

121 123 125

8 CASE HISTORIES

127

APPENDIX A. TYPICAL SPACING TABLES

139

APPENDIX B. SITE SELECTION DATA REQUIREMENT LIST

151

REFERENCES

179

GLOSSARY

183

INDEX

191

Preface

The Center for Chemical Process Safety (CCPS) The Center for Chemical Process Safety (CCPS) was established in 1985 by the American Institute of Chemical Engineers for the express purpose of assisting industry in avoiding or mitigating catastrophic chemical accidents. To achieve this goal, CCPS has focused its work on four areas: • Establishing and publishing the latest scientific, engineering and management practices for prevention and mitigation of incidents involving toxic, flammable, and/or reactive materials • Encouraging the use of such information by dissemination through publications, seminars, symposia, and continuing education programs for engineers • Advancing the state of the art in engineering practices and technical management through research in prevention and mitigation of catastrophic events • Developing and encouraging the use of undergraduate engineering curricula that will improve the safety knowledge and consciousness of engineers This book outlines a process for finding an optimal location for a chemical or petroleum processing site and then arranging the units and equipment. It provides comprehensive guidelines on how to select a site, how to recognize and assess long-term risks, and how to lay out the facilities and equipment within that site. A survey guide is provided to aid site selection teams in obtaining necessary data to select a new site. Site layout and equipment spacing guidelines are provided based on historical and current data including industry practices and standards. Spacing tables are provided which can be used as a starting point in laying out a site. Case histories and examples are included to illustrate both the appropriate manner in which to address facility siting and layout as well as the consequences when the effort is inadequate. ix

Acknowledgments

The American Institute of Chemical Engineers and the Center for Chemical Process Safety express their gratitude to all the members of the Facility Siting and Layout Subcommittee for their generous efforts and valuable technical contributions in the preparation of this Guidelines book. Chairs: Ephraim A. Scheier Frank Worley, III

BP America, Inc. Rohm & Haas Company

Authors: Cheryl A. Grounds Joseph R. Natale

Baker Engineering and Risk Consultants Baker Engineering and Risk Consultants

CCPS Staff Consultant: John A. Davenport Subcommittee Members: John A. Alderman Richard L. Alexander, Jr. Michael P. Broadribb Chris R. Buchwald Christopher P. Devlin Brian R. Dunbobbin Rodger Ewbank William Hague Andrew P. Hart John Marshall Michael D. Moosemiller Henry Ozog

RRS Engineering formerly with Solutia BP America ExxonMobil Celanese Chemicals Division Air Products & Chemicals Rhodia Honeywell Specialty Chemicals Nova Chemicals Dow Chemical formerly with Det Norske Veritas (DNV) ioMosaic Corporation xi

xii

Acknowledgments

Vanessa E Rodriguez John R Sharland William E. Thornberg Tracy Whipple

US Environmental Protection Agency FM Global formerly with GE Global Asset Protection Services formerly with Det Norske Veritas (DNV)

Before publication, all CCPS books are subjected to a through peer review process. CCPS also gratefully acknowledges the thoughtful comments and suggestions of the peer reviewers. Don Connolley Kieran J. Glynn Hal Johnson Neal W Johnson Neil Macnaughton Jack McCavit Lisa Morrison Tim Overton Phil Partridge Janet L. Rose Scott Schiller Orville M. Slye, Jr., PE Anthony Thompson Jan Windhorst Jeff Yuill

Akzo Nobel Chemicals Inc. British Petroleum ConocoPhillips ConocoPhillips British Petroleum Celanese NOVA Chemicals, Inc. Dow Chemical Company Dow Chemical Company Bayer Polymers LLC ConocoPhillips Loss Control Associates Monsanto Company Nova Chemicals, Inc. Starr Technical Risks Agency, Inc

1

Introduction

1.1. Objectives The cost, complexity, and safety of process operation and maintenance is highly dependent on site location and layout. Building inherent safety into a site generally reduces both the cost and complexity. Siting and layout are among the earliest steps in design, and are quite costly to modify once the site is constructed. Optimum siting and layout minimizes material and construction costs, but more importantly, minimizes the risk of losses throughout the site’s life cycle. What principles do you use to decide on the location and layout of a new or expanded site? What information do you need to consider before selecting a site location? How do you maximize inherently safer design with minimal impact on cost and schedule? How do you manage siting issues when limited space is available? How to you address security concerns in a new site? This book addresses siting and layout in terms of the overall process of finding an optimal location for the site and then arranging the units and equipment. It provides comprehensive guidelines on how to select a site, how to recognize and assess long-term risks, and how to lay out the facilities and equipment within that site. Site layout and equipment spacing guidelines are provided based on current industry practices and standards. This book is applicable to the following types of facilities. • Large and small. • Petroleum and chemical facilities and other industries using petroleum or chemical products • Within and outside of the US. • Grassroots sites, brownfield sites, and expansions within a site. • Open air sites • Processes enclosed in a building (in terms of siting the building, not in terms of process equipment layout inside of the building) 1

2

Guidelines for Facility Siting and Layout

The objectives of these guidelines are to provide guidance on the following points. • Approaching siting and layout from a safety perspective • Assembling a site selection team, compiling the issues they need to consider, and determining what data they should collect (This information is needed for selecting a location for a new grassroots site, a brownfield site, or an expansion within a site.) • Balancing infrastructure, environmental, security, population, and process risk considerations with each other in the site selection process. • Anticipating outside factors that may affect the project cost and schedule. • Fitting a new expansion within an existing unit and compensating for limited spacing by taking risk mitigation measures. • Maximizing inherently safer design in siting and layout by gathering data and conducting hazard analysis in the conceptual design and layout stages of the site design. • Maximizing ease of operations and maintenance as well as minimizing operating and maintenance risks to personnel and the surrounding site through layout and equipment spacing. This book will benefit anyone responsible for making or advising on siting decisions. Project developers will find the information they need to collect and/or develop in order to select a site. Planners and those who evaluate the economic justification for a site will learn of the potential safety and risk impacts of siting decisions. Designers and engineers will appreciate the technical details included in specifics given on plant and equipment layout and spacing.

1.2. How To Use This Book This book may be considered the starting point for establishing the criteria needed to make decisions on the location of a grass roots site or new unit within an existing site, as well as the basic equipment layout and spacing within the site. This book discusses the sequential steps taken in this process as outlined in Figure. 1-1.

1 Introduction

3

Figure 1-1. Guidelines Book Flowchart

It is important to use consistent vocabulary when discussing the components and subcomponents of a process complex. Figure 1-2 shows the terminology used in this book. A unit is a collection of process and/or manufacturing equipment that is focused on a single operation. For example, a refrigeration unit supplying a frozen food plant, a crude distillation unit, a water treating unit chlorinating waste-water effluent from a waste disposal facility, a polyethylene unit, or a batch reactor train. A plant is a collection of process units with similar process parameters or related by feeding or taking feed from each other. For example, a fuels plant which produces materials for blending gasoline, a lubricating oil blending plant, a tank farm area supporting a refinery, chemical site or both, a wharf receiving raw materials and loading products, a polypropylene processing and plastic pellet silo storage area, a pipeline pumping station. A site is a collection of plants typically owned by a single entity. A site may have its own support facilities or share them with another site. Support facilities may include parking, offices, maintenance, and warehousing facilities, firehouse, medical, transportation, and security facilities. Examples of

4

Guidelines for Facility Siting and Layout

Figure 1-2 . Guidelines Terminology

a site may include a petroleum refinery, or a manufacturing facility that produces a variety of products such as paints, synthetic rubbers for tire manufacturing, or petrochemicals. A complex is a collection of sites that may or may not be owned by the same business entity. A site within a complex may feed or take feed from another site within the same complex or be totally independent. This book provides a selection of examples throughout the text and case histories in Chapter 8. These case histories and examples serve to illustrate both the appropriate manner in which to address facility siting and layout as well as the consequences when the effort is inadequate. These case histories include actual events, scenarios based on real events but modified to emphasize a point, and purely illustrative examples.

1.3. Layers of Safety Siting and layout provide a fundamental aspect of risk management. It separates sources of potential fire, explosion, or toxic incidents from adjacent areas that might become involved in the incident or be harmed by its potential consequences. This is also a key component in inherently safer design.

1 Introduction

5

Inherently safer strategies can impact a potential incident at various stages. The most effective strategy will prevent initiation of the incident. Inherently safer design can also reduce the potential for an incident to escalate. Lastly, an inherently safer strategy can limit the incident sequence before there are major impacts on people, property, or the environment. (CCPS, 1996, no. 23) There are many challenges to the ability to site and lay out a plant as will be discussed in these guidelines. Layers of safety are utilized to compensate for less than desired spacing and to implement additional aspects of inherently safer design. This use of layers of safety or layers of protection is a traditional risk management approach and is illustrated in Figure 1-3. These layers may include the inherently safer strategies of preventing the incident, minimizing escalation, and minimizing impact. The layers may include using a less hazardous process, separation distances, operator supervision, control systems, alarms, interlocks, physical protection devices, and emergency response systems (CCPS, 2001). Consider layers from inside to outside following inherently safer concepts: 1. Process design 2. Separation distance 3. Safety and process devices, instruments, alarms, and controls 4. Administrative processes and controls

Figure 1-3. Layers of Safety

6

Guidelines for Facility Siting and Layout

1.4. References 1.4.1. CCPS Publications Where appropriate, reference is made to other CCPS books for additional guidelines and methodology for specific applications. The most relevant CCPS Publications are listed here. Guidelines for Evaluating Process Plant Buildings for External Explosions and Fires. Chapter 5 provides general guidance on locating buildings within the site with relation to other facilities (CCPS, 1996, no. 22). Guidelines for Chemical Process Quantitative Risk Assessment and Guidelines for Hazard Evaluation Procedures provide additional guidance on conducting risk assessments. Risk assessment may be applied in many siting decisions (CCPS, 2000 and CCPS, 1992). Inherently Safer Chemical Processes—A Life Cycle Approach discusses inherently safer design (CCPS, 1996, no. 23). Layer of Protection Analysis: Simplified Process Risk Assessment describes layer of protection analysis (CCPS, 2001). Guidelines for Analyzing and Managing Security Vulnerabilities of Fixed Chemical Sites describes security measures and analysis techniques (CCPS, 2002). Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities describes fire protection measures that may be applied to the site and the equipment on the site (CCPS, 2003, no.29).

1.4.2. Other References Where appropriate, this book references pertinent American Petroleum Institute (API) Practices, National Fire Protection Association (NFPA) Codes, and American Society of Mechanical Engineers (ASME) Codes. References are generally made to US codes and practices; recognizing that when the site is located outside the United States, there may be non-US codes and regulations that override the references in this book. A complete list of all referenced industry practices, including applicable CCPS books, is included in the References at the end of this book.

2

Management Overview

Example In 1969, the site started to produce the pesticide SEVIN. Methyl isocyanate (MIC), an intermediate chemical, was imported from another location. In the late 1970s, the site added a MIC production unit. [Originally] the site was located approximately 3–4 miles outside the city center. At the time of the incident, the site employed 630 people. The city had a population of 900,000 people with a community of squatters situated immediately outside of the site boundary. Just after midnight there was an accidental release of approximately 40 metric tons of MIC into the atmosphere. Thousands of people lost their lives, hundreds of thousands were injured, and significant damage was done to livestock and crops. The plant was located in Bhopal, India. [Reproduced with the permission of the United States Chemical Safety and Hazard Investigation Board, CSB, 1999.]

Lesson The siting of a new facility and the purchase of surrounding land to control community encroachment is critical to risk management.

2.1. Implications of Siting and Layout Appropriate siting and layout establishes a foundation for a safe and secure site. A site that is well laid out will have a lower risk level than a poorly laid out site. The potential for toxic impacts, fire escalation, and explosion damage will be lower. The risk to personnel and the surrounding community will be reduced. Additionally, maintenance will be easier and safer to perform. However, these benefits do not come without associated costs. Separation distances translate to real estate that costs money. Tradeoffs between initial capital investment, life cycle costs, and risk reduction are inherent in siting and layout decisions. 7

8

Guidelines for Facility Siting and Layout

2.2. Management of Risks Consideration of siting and layout is an important aspect of risk management. Managers must address several types of business risks, including the risks from costly potential incidents. The approach in this book is to find a site location and layout that will minimize risk to site and community personnel and property while maximizing the ease of safe operation and maintenance. This approach may reduce the total life cycle cost. The guidance in this book is aimed at maximizing the use of inherently safer strategies in the design to build in safety and risk reduction. Inherently safer design strategies may prevent initiation of an incident, reduce the potential for incident escalation, and limit the incident consequence before there are major impacts on people, property, or the environment (CCPS, 1996, no. 23). Appropriate siting and layout separates sources of potential fire, explosion, or toxic incidents from adjacent areas that might become involved in the incident or be harmed by its potential consequences. Thus, siting and layout not only provide for a fundamental aspect of risk management but are also key components in inherently safer design. The many challenges associated with plant siting and layout are discussed in this book. Layers of safety are utilized to compensate for less than desired spacing and to implement additional aspects of inherently safer design. This use of layers of safety or layers of protection is a traditional risk management approach and is illustrated in Figure 1-3. These layers include the inherently safer strategies of preventing the incident, minimizing escalation, and minimizing impact. The layers may include using a less hazardous process, separation distances, operator supervision, control systems, alarms, interlocks, physical protection devices, and emergency response systems. Although safety protective systems are often necessary, they are less reliable and more costly to maintain than the protection afforded by inherently safer design strategies (CCPS, 2001).

2.3. Basis for Facility Siting and Layout Building a new site or adding equipment to an existing one is often an exciting, but daunting, proposition. If it is done well, capital is well invested, goals are met, and the future looks promising. If it is done poorly, money may be wasted, goals unachieved, and the future could be unwittingly compromised.

2 Management Overview

9

In designing and building a project, the difference between these two outcomes is greatly influenced by consideration of siting, layout, and other inherently safer design concepts early in the project evolution. If these fundamental issues are addressed too late, costly changes may be required, opportunities for cost-effective protection may be unrecognized, and the new site could actually increase company liability. The importance of timely consideration of inherently safer principles is depicted in Figure 2-1. Application of inherently safer design concepts to the design and layout can identify the need for process modifications or alternative site arrangements. The solution may cost more initially (more infrastructure, more land, longer piping runs, and greater unit spacing); however, life cycle costs will be lower. Some savings are realized through reduced losses due to potential fires, explosions, or toxic releases. In addition there will be savings resulting from lower costs for managing risk (fewer protection systems requiring maintenance, ease of maintenance, ease of operations, and lower insurance costs).

Figure 2-1. Safety in Project Development

10

Guidelines for Facility Siting and Layout

Figure 2-2. Guidelines Book Flowchart

It is helpful to follow a sequential process to site and lay out a new project. This process is illustrated in Figure 2-2. This book will discuss and follow this sequential process. 1. First a team should be assembled to determine what issues need to be considered and what data to collect. This may seem obvious and experience shows that the effort spent in selecting a team with the right credentials for a specific project assures a more thorough assessment of the sites under evaluation and will pay-off in the end. Environmental, population, and process risk considerations must be balanced with each other and costs in the site selection process. Also, outside factors that may affect the project cost and schedule should be anticipated. 2. Once the site is chosen, the various components of the plant can be located with respect to each other. Issues such as topography, wind direction, and process risk come into play. Fitting a new expansion within an existing unit is often a challenge and may require additional fire protection or other safeguards due to space limitation.

2 Management Overview

11

3. Finally, the individual unit equipment can be laid out. Equipment spacing should maximize ease of operations and maintenance thereby minimizing operating and maintenance risks to personnel and the surroundings. This spacing will also aid in minimizing congestion, which will reduce potential explosion overpressures. Site security should be considered. Site layout and typical equipment spacing guidelines are provided based on current industry practices and standards.

2.4. Changing World Societies increasingly demand higher standards for processing sites. These standards include cleaner effluents and greater assurances of a safe operation. The demands for higher standards will continue resulting in the benefits of a new or modified site being weighed against the risks to the community. One must also be aware that attitudes to risk change with time. What may be acceptable to a neighboring community today may be undesirable tomorrow. Periodic review of risk tolerability is necessary as the technology advances, the process changes, the site expands, the regulations change, and the surroundings outside the fence change. Increased spacing provides better flexibility as future demands evolve. A damaging incident lowers the credibility of the engineering that went into building the plant. It is worth investing a little more time and money up front to proactively incorporate greater risk reduction measures into the design than current regulations, codes, and standards identify, to ensure the long-term viability of the facility.

3

Preparing for the Site Selection Process

There is never any substitute for good planning and preparation when taking on any complex task. Site selection is a very complex process fraught with many unknowns and concerns that are difficult to resolve. From a safety perspective, choosing a site that is not adequately sized or where the impact on adjacent sensitive neighboring sites has not been determined may result in additional prevention or mitigation measures being required. These measures generally include the need for expensive, maintenance-intensive, and attention-demanding protective systems to counter potential exposure risks. This additional expense may have been avoided by an alternate location or by a larger site. Thinking ahead about potential issues of concern and identifying the information you need to develop before the site selection process begins is a very cost effective effort. What are we trying to achieve in the preparation phase of the site selection process? Our objectives include the following: • Identify, early on, issues associated with each site under consideration that may become a concern later in design or operation; • Collect critical information necessary to make decisions regarding the location, size and layout of a site; and • Ensure maximum opportunity to incorporate the principles of inherently safer design and layout of a new or expanded site with minimal impact on project cost and schedule. This chapter provides guidance and discussion on a number of issues to consider in preparing for the site selection process. It is presented as a list addressing the objectives above. Guidance is provided on information to collect or develop and where to find the information. Guidance is also provided on how the collected information is likely to be used during the permitting, design, construction, and future operation of the site. The content is comprehensive and applicable worldwide. Much of the information discussed will not necessarily be needed for all types of projects. 13

14

Guidelines for Facility Siting and Layout

The information obtained using these guidelines should be sufficient to allow feasibility or scoping studies for budget estimates and to anticipate potential major downstream impacts on a project. This chapter deals with the following steps listed in sequence: 1. Describe the new site and planned uses for the site 2. Define the team of experts needed to assess potential sites 3. Decide on the site size (How much land area do I need?) 4. List information required to assess the location with respect to neighboring sites, e.g., preliminary hazard analysis 5. List information required prior to site surveys 6. Detail environmental considerations at pre-site selection stage

3.1. Project Description A project description is needed to guide the selection teams. This will provide the information that will be needed in evaluating a potential site or sites. This document should include as much information as is known and specifics on what is desired at the new site. The following is a suggested content for the project description: • Project scope: —What is the purpose of the new plant or facility? —Who and where are key customers for the products? —Who and where are the key suppliers for feed stocks? —What is the planned level of staffing for operation and maintenance of the site? Are specialized outsourced maintenance and/or inspection skills required? —What are the primary considerations for the anticipated sites including locations, contacts, potential consultants, security concerns, permit requirements, and climate conditions? —Is a future expansion being considered? Should site selection anticipate additional land for expansions or future facilities? Could the same site and equipment be utilized for a new process involving different chemicals and reactions? • General site location information: —Are qualified operations and maintenance staff available in the region?

3 Preparing for the Site Selection Process

15

—Will the site be shared with another operation? If so, with whom? List other shared or owned operations, staff, and/or facilities on the new site (office buildings, day care facilities, warehousing, storage facilities, utilities, security staff, maintenance staff, site management staff, and emergency response staff and equipment). —What specific infrastructure is desired at the potential sites (e.g., are marine facilities required; is it intended that the site will purchase power or is power generation a consideration; utilities, rail, and roads)? —Are there known security risks in the region (adversary characterization)? —What is the availability of external firefighting resources and mutual aid? —Is there land surrounding the site to allow purchase of, or control of, that land to provide a buffer zone? —If the new plant is to be built on an existing site, what field data may already be available to minimize the data collection effort? —In what language is the local workforce fluent? —What languages are used in communication and design documentation? —What standard system of units and measures should be used? —What is the earthquake zone in the area? —Is the area subject to hurricanes or typhoons or other severe weather conditions? • Detailed description of the plant and processes: —List raw materials used, and intermediates and products made, including any alternative raw materials, catalysts, or additives that may be considered. —Identify fundamental hazards of materials and products: e.g., flammability and toxicity. —Tabulate production rates, expected inventory levels, and maximum hazardous material inventory levels. —List known process technologies that will be employed. Are proprietary technologies planned or under consideration? —Define the automation level that is envisioned. Will the plant be fully automated versus manual? (This will affect spacing and layout.)

16

Guidelines for Facility Siting and Layout

—Describe the means of feedstock and product transportation (truck, rail, ship, pipeline, by company owned means or contract). List cargo sizes and frequencies of shipments in and out of the site —List the design concepts employed in developing the process that may affect the layout and spacing of the site, i.e., enclosed loading vs. outside loading. —Identify the turnaround philosophy (shuts down once every two years, or continued operation with individual process shutdowns as required). —Identify the expected life of the plant (10 year, 20 year, or other). —Identify the desired on-stream factor. —Identify requirements for waste disposal. • Points of special interest to include: —Known process safety hazards associated with the process including any past incidents from similar facilities. —Regulatory issues associated with the chemicals. —Experience at other similar facilities with community concerns or productivity issues (e.g., noise, odors, traffic issues, or high personnel turnover). —Special security or design measures required at the site due to the materials used or produced (explosives, toxic agents, or precursors to either), or to the proprietary nature of the site. —Anticipated permitting concerns or environmental issues related to the site construction and/or operation. —Community concerns regarding potential site development or expansion. —Activities at neighboring facilities that may impact on the new facility. —Public infrastructure required such as an interstate interchange or a railway bridge overpass. —Potential environmental liability concerns associated with expansion to existing or with former industrial sites. The project description sets the stage for what the site survey team will be looking for and what level of detail will be needed to select a site.

3.2. Assembling a Site Selection Team Assemble a team to organize, collect and analyze data, develop information, and conduct site surveys in order to form recommendations regarding the selection of potential sites. The team make-up should provide the expertise

3 Preparing for the Site Selection Process

17

needed to meet the unique requirements for a specific type of plant as well as a particular site location. The following is the type of expertise that may be required for a specific site selection task: • Knowledge of the types of plant and processes under consideration for the new site • Knowledge of site layout • Knowledge of the specific areas where the new site is planned or being considered • Familiarity with the local language • Familiarity with the local regulations • Specialists (engineer, scientist, or other person with the appropriate expertise): —Marine design specialist who can evaluate potential sites along the coast for deep water ports such as for Very Large Cargo Carrier (VLCC) crude tanker access —Environmental specialist who can evaluate wastewater, ground water, and air issues. —Civil specialist to evaluate sites with complex topography and soil conditions —Process safety or risk specialist who can assist with process safety issues, on-site risk concerns, and off-site risk concerns. —Security specialist who can assist in physical security considerations. This expertise may be from in-house resources or a third party consultant firm. The following example demonstrates the team selection process.

Example You are building a process site in an area where you have limited or no operations at present. Your team make-up includes a project engineer with experience in the process operations, process safety engineer, security expert, and a local manager with several years experience in the same state but not with new construction. No one on the team has any experience with local building officials or new construction regulations in the region where the site is being evaluated. Your team needs local contacts and expertise. Find someone within the company or hire a consultant that can help collect and interpret the local regulations, and assist in preparing information required for permitting. This expertise concerning the area, local govern-

18

Guidelines for Facility Siting and Layout

ment, concerns that may exist regarding other industrial sites, and possibly knowledge of useful contacts can save you much time and assure a faster and more complete assessment of the site. The new process site will require access to marine facilities for both raw material import and product transfer. The new site will therefore be very dependent on access to reliable marine facilities that meet the capacity requirement for the new site. Your company has extensive marine facility operating experience; however, there is no in-house expertise in marine facility design or knowledge of the marine facilities in the area of the proposed site. Utilize a marine engineering specialist to survey and evaluate existing marine facilities for the team.

Lesson Selecting a site involves consideration and analysis in many specialized areas. Assure that the site selection team has the appropriate expertise to evaluate the specialized needs required for that site.

Tasks like those described in the example may require hiring consultants with specialized expertise. Two things to consider when identifying outside resources: • It is important to set aside adequate time to evaluate contractor and/or consultant capabilities to assure your selection is a good fit for the project. • It is equally important to prepare a project description in sufficient detail to assure the consultant understands the basis for his involvement and exactly what his mission is in support of the site selection process. This may seem obvious, but experience shows that the effort spent in selecting a team with the right credentials for a specific project assures a more thorough assessment of the sites under evaluation and will pay off in the end. The site selection team should work to a schedule that allows enough time to collect all data needed for the selection analysis. However, it is often not possible to gather all the information desired in the time available at the site. In this case, the team should develop a plan for acquiring the remaining data at a later date. This follow-up plan needs to be considered in setting the time schedule for the overall site selection process. In the case where a new plant or facility is being located within an existing site, it may be beneficial to assign a local company representative to forward information obtained at a later date to the site selection team, or possibly have a local person on the team.

3 Preparing for the Site Selection Process

19

3.3. Preliminary Site Size Determination Once the project description is written, a preliminary estimate can be made for the size of the site to accommodate the facilities desired. Process plot sizes may be based on similar existing process sites. However, when basing a new design on an existing facility, one must consider the existing shortcomings in order to prevent repeating old mistakes. Many existing plants do not have a layout to make them inherently safer. Preliminary plot sizes can be estimated by the process licensor, engineering contractors, or in-house engineering specialists that have experience in building similar processes. An engineering and/or construction contractor can also estimate plot sizes for other types of facilities, e.g., parking lots, buildings, warehouses, storage tanks, and utility areas, if the task cannot be done in-house. Guidelines in Chapter 5 offer information regarding the typical spacing between facilities and property lines. As an example, if your site needs to contain one process area, offices, and utilities, then a preliminary site size determination may result in a plot area that looks like Figure 3-1.

Figure 3-1. Preliminary Plot Area (1 ft equals 0.348 m; 1 acre equals 4074 m2 or 43,560 ft2)

20

Guidelines for Facility Siting and Layout

This preliminary estimate provides an idea of the land area required to fit all the facilities required on the site. Greater separation distances may be employed to provide security clearances either inside or outside of the site perimeter or to limit access to critical site areas.

3.4. Preliminary Hazard Screening Identify and consider all potential exposures that may affect the location of a new plant during the site selection phase. As stated in the last section, these potential exposures may be to the new plant from an adjacent plant or from the new plant to neighboring areas. The latter may include potential hazards to community areas, other industrial sites, and/or environmentally sensitive areas. Make an effort to ensure the location and land area chosen for the new site is adequate to anticipate permitting, design, and layout concerns that can arise later in the project. A useful process for identifying the potential exposures to a new plant from an adjacent hazard, or from the new plant to the surrounding area, is a preliminary hazard screening. Early in the site selection process, it is not necessary to conduct a detailed, costly risk assessment. A hazard screening analysis will provide the information needed to determine if the site provides adequate separation distance from neighboring areas. The preliminary hazard screening analysis is based on the process data developed to-date and the preliminary plot area. In the preliminary hazard screening, focus on those events with the potential for off-site consequences. The consequence analysis will identify both on-site impacts and off-site impacts. The on-site events tend to drive the spacing within units and plants. The off-site events tend to drive overall layout and site selection. With the preliminary hazard screening as a basis, the results will address the question at hand, which is whether the preliminary plot area is appropriately sized. This preliminary hazard screening could show that the preliminary plot area was a good estimate and only minor modifications are needed. However, the preliminary hazard screening could also show that the impact area is larger than desired in which case increasing the plot area to add buffer distance could be an appropriate mitigation measure. A toxic release, fire, or explosion may also be due to sabotage or a terrorist action. The impact of these events should be considered in the preliminary hazard analysis and a security vulnerability analysis.

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3.4.1. Preliminary Hazard Analysis A preliminary hazard analysis is used to identify the main concerns associated with a specific type of plant and does not require detailed design drawings (CCPS, 1992). A preliminary hazard analysis is usually done during the early stage of a project when the plant location and layout is being considered and prior to development of any process design details. The information used in the analysis is in the project description discussed in Section 3.1. The typical hazards of concern include: toxic releases and flammable releases leading to fires or explosions with potential consequences on people, property, and the environment. These typical hazards may also address potential security threat scenarios involving explosions or release of toxic materials. Typical team composition and analysis methods for preliminary hazard analyses are described in the CCPS Guidelines for Hazard Evaluation Procedures (CCPS, 1992). The next step, then, is to identify the potential consequences. These consequences include potential toxic exposures, fires, or explosions. Methodologies for estimating the potential consequence of both toxic and flammable vapor releases can be found in a variety of resources. The CCPS book, Guidelines for Consequence Analysis of Chemical Releases, provides information regarding how to evaluate the consequences from various hazards including explosions, flash fires, and toxic releases (CCPS, 1999). Computer-based models are available that estimate vapor cloud dispersion, heat radiation from fires, overpressure from explosions, and toxic concentration downwind of toxic releases. Many simple models overestimate the consequence; however, these models provide adequate consequence estimates for the site selection process. A preliminary hazard analysis may also identify potential environmental concerns to consider when choosing a plant site and deciding on the amount of land area required for the plant facilities. Environmental control issues are discussed later in this chapter. In some locations, specific regulatory requirements may govern levels of risk, as opposed to hazard, on the site and its surroundings. In these cases, not only consequences but also likelihood must be evaluated.

3.4.2. Toxic Release Scenarios Toxic releases, whether originally liquid or vapor phase, usually have their most significant impact as a vapor cloud. The extent of the hazard depends on the vapor properties and conditions at the time of the release. Large release incidents for materials like anhydrous ammonia or chlorine can be lethal for great distances downwind, particularly if initially released as a liquid.

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Established design and operation guidelines help minimize the hazard of large releases (for example, safe handling and transport). However, the site selection team may not know at this point in time what safeguards will be built into the plant to compensate for these toxic hazards. So what do you need to consider in terms of siting when evaluating the hazards associated with toxic releases? Chemical and petroleum industry accident data show that most releases involve equipment failures and occur from: • Pump seal leaks • Piping or hose leaks • Piping or hose failures • Sample points, vents, drains, plugs left open or broken off During the preliminary hazard analysis, consider those more severe incidents that may pose off-site exposure concerns to neighboring sites. At this stage in the screening analysis, a range of scenarios can be selected from the above list to provide insight on the adequacy of the plot area or the size of buffer zone required. These potential exposures may affect the permitting process and result in future costly prevention or mitigation systems to compensate for separation distance. The following examples illustrate how the potential consequences of incidents are used to determine site land requirements.

Example Site A

A new water treatment facility is being considered on a site that is located 1 mile from a residential area. The facility will use chlorine that will be stored in 1-ton portable cylinders. Checking the industry standards, there is no prescriptive guidance regarding the spacing requirements for using or storing chlorine cylinders with respect to exposure hazards to property lines or other facilities on a site. A preliminary hazard analysis identifies a potential hazard of the cylinder ¾-inch fusible blow out plug failing. The potential consequence of the full cylinder release shows toxic chlorine exposure levels beyond the property boundary.

Site B

A new site uses pressurized ammonia gas for making fertilizer. The site is located in an area where a housing community is located 1968 feet (600 m) away. A credible incident identified during the preliminary hazard analysis is a vent line failure on the charge line to the process. The company uses Emer-

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gency Response Planning Guideline (ERPG) 3 as a screening criterion. The ERPG 3 value for ammonia is used as a toxic endpoint exposure maximum at the property boundary for the site. The potential consequence estimate for the vent line release showed that the ERPG 3 level goes as far as 3300 feet (1000 m) downwind based on total loss of the content of the tank when at normal operating level. Risk reduction options are considered including reduction of on-site inventory of ammonia and storage in smaller vessels. These options however are not favorable from a processing viewpoint. As a result of the consequence analyses, the owners of both sites may want to consider the following: 1. Can an inherently safer chemical (e.g., using sodium hypochlorite instead of chlorine in the first example) be used instead? If the original chemical is the only choice, can smaller containers be used to store it? Can the operation take place inside a containment area (building enclosure) where releases can be mitigated more effectively? 2. Can good separation be achieved if the operation is located within the site at the furthest point from the neighboring sites? 3. Can additional land area be acquired to provide a greater buffer area between the facility and the neighboring sites? 4. Consider future land use around the new site. Will there be further development around the site that will cause future off-site exposure concerns? 5. Can a separate site be considered which is more remote to sensitive neighboring sites?

Lesson The release of toxic chemicals may have impacts on people and the environment beyond the fence line. A preliminary hazard analysis and consequence analysis may be used to determine the potential impact, site the material handling appropriately, and prompt the consideration of hazard reduction measures. There may be a number of possible reduction measures for a hazard. Consider inherently safer options first. Evaluate the effectiveness and feasibility of all options.

3.4.3. Fire Scenarios Fire is an example of a credible incident resulting in off-site exposures from high radiant heat (thermal flux) levels. Scenarios for consideration may include radiant heat from:

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Guidelines for Facility Siting and Layout

• A process unit fire. • A truck or rail car loading rack fire resulting from hose failure. • A pool fire in a dike or impoundment area resulting from the overflow of a storage tank. • The flare during maximum flare system loads due to a power failure, loss of cooling water, or an emergency shutdown. • A full surface area fire in flammable or combustible storage tanks. A potential consequence estimate for a heat radiation (thermal flux) exposure to a neighboring facility or community area can be estimated quickly using typical process conditions and equipment sizes. Guidelines in this book include spacing distances between equipment and facilities from property lines. These spacing guidelines are generally sufficient to minimize heat radiation exposures from tanks and process area fires. With regard to exposures to other facilities on a shared site, this book contains typical spacing and layout that will provide separation to minimize exposure to the plant from most typical industrial site hazards. However, consider severe hazard exposures identified in the preliminary hazard analysis to determine if additional separation is required. Consider the potential for business interruption as well as damage to equipment and exposures to personnel in the determination of additional separation needs. A methodology for estimating pool, flash, and jet fire heat radiation levels is included in the CCPS Guidelines for Consequence Analysis of Chemical Releases (CCPS, 1999). Criteria for safe heat radiation exposure levels that can be used as criteria to estimate a safe distance to adjacent plants or facilities may be found in API RP 521.

3.4.4. Explosion Scenarios Damage from an explosion is caused by the resulting blast wave, thermal radiation, flying debris, or toxic release. There are many different types of explosions including a vessel rupture explosion and a vapor cloud explosion (VCE). Explosion phenomena are discussed in the CCPS Guidelines for Evaluating the Characteristics of Vapor Cloud Explosions, Flash Fires, and BLEVEs (CCPS, 1994) and Understanding Explosions (CCPS, 2003, no. 30). Those facilities handling flammable vapors and reactive chemicals must consider the impact of potential explosions on the site and surrounding community. Additionally, exposures from surrounding facilities impacting the new site should be considered. VCE overpressures may be influenced by the size of the vapor cloud and aspects of plant layout such as the openness of the area

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and amount of equipment within the cloud. Explosion hazards may be mitigated by redesigning the process chemistry, relocating exposures, designing blast resistant structures, and providing greater separation distances. An explosion may also be due to sabotage or a terrorist action. The impact on the surrounding community or the economic system should be considered in the siting and layout. For combustible solids handling operations it is common practice to provide explosion venting on equipment operating with potentially ignitable atmospheres. Since the fireball from these vents can extend large distances, horizontally arranged vents should be arranged to minimize exposure to adjacent areas. In some cases it may be necessary to move equipment, such as large silos, to a remote corner of the operational block to make explosion venting a viable option for explosion protection. Another option may be to locate equipment outdoors if explosion venting is not feasible. Typical explosion scenarios may include (CCPS, 1994): • A physical explosion such as a vessel rupture or a BLEVE • A chemical explosion caused by a decomposition or rapid exothermic reaction of reactive chemicals • A deflagration or detonation of a flammable vapor cloud

Example A new $100 MM specialty chemicals plant is being considered on a shared site with another chemical company that produces ethylene. The existing chemical plant has ethylene cracking and separation facilities. The separation distance between the new plant site and the existing ethylene facility property line is 250 feet (76 m). A preliminary hazard analysis of the new plant identifies a potential for incidents involving fires due to release of flammable liquids and tank fires. From an insurance perspective, the physical damage loss for the new plant from these fires is estimated to be $10 MM. The exposure hazard to the new plant from the ethylene cracking facility is also considered in determining the amount of insurance required for the new plant. The potential hazard and consequence associated with the ethylene facility is identified as an ethylene release and subsequent vapor cloud explosion. The consequence of the explosion is destruction of the new specialty chemicals plant. The loss is determined to be the cost of a replacement plant. The additional cost of the premium may provide justification to allow more separation distance or consideration of an alternate site.

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Lesson

Hazards may be posed either from a site onto its neighbors or from the neighbors onto the site. In some cases, cost benefit analysis may show that the benefit of greater separation distances to minimize the hazard is worth the increased real estate cost.

3.4.5. Refinement of Preliminary Plot Area With the potential consequence estimates completed, preliminary hazards for off-site toxic, fire, and explosion consequences may be compiled. With this data, the preliminary plot area size can be evaluated. The data may show that the hazards meet the regulatory or corporate guidelines and therefore, the preliminary plot area is appropriate. However, the hazards could be outside of the guidelines and measures to reduce the hazard may be warranted. These measures could include reconsidering inherently safer strategies: eliminating the problem by substituting chemicals, mitigating the potential consequences by reducing storage quantities or changing storage location, or mitigating the impact on the surrounding community by, adding a buffer zone or choosing a different site entirely. When the hazards impact sensitive populations, the latter is a very appropriate solution.

3.5. Guidelines for the Survey and Data Collection Effort To make this book appropriate for a broad range of projects, each section includes a variety of related topics that may or may not be applicable to a specific project. The intent is to provide enough information to permit a good survey and data collection effort for any type of new site or plant anticipated. The reader will need to pick and choose those topics that apply to the specific project of interest. In the end, the site survey effort should produce sufficient information to permit development of a scoping level study based on a specific site for budget estimate. The site selection team can develop a project-specific checklist for data collection during the site survey. The checklist is used during the site survey as a guideline to assure that data is complete and organized. The Site Survey Data Requirement List in Appendix B and discussed further in Chapter 4 can provide the foundation for developing a project-specific checklist. The project-specific checklist should include the purpose of the project, a process description, and a design philosophy as it relates to future expansions and reliability of operation. This information will be available from the project description discussed in Section 3.1.

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3.5.1. Codes, Standards, and Local Requirements The site selection and data collection effort will include acquiring copies of codes, standards, and local requirements that pertain to various equipment and design criteria. Codes and standards must be considered on the federal, state, and local level. The federal codes and standards may not be the most stringent. Of specific interest are those codes and standards for pressure vessels, tanks, boilers and related equipment, piping, electrical design, buildings (including architectural design), storage, plumbing and sanitary facilities, structural steel, reinforced concrete, fire protection, and safety. Where engineering is being performed in a country other than where the site will be constructed, there may be different codes and standards. It may be helpful to make a list that cross-references the applicable local codes and standards between the countries. The list can then be used to identify the differences between the codes and standards and any associated impact on cost of compliance. Where there are differences in regulations, or if regulations do not exist for a specific topic, determine what regulations are acceptable for use in place of corresponding regulations. If not, which regulations must be used? Is the local code more stringent? What is the impact on project quality and cost? Is it possible to get a variance? How does one apply for a variance? Other issues to consider include: • Qualification requirements for specific crafts. For example, welders in the United States must qualify based on specific codes. Can welders at the site location be qualified for the relevant codes? • Local restrictions on import of foreign construction materials such as a steel design code that may not permit the use of foreign steel. • Specific local requirements regarding inspections, quality assurance, hardness, and corrosion allowance. • Specific local codes or standards regarding spacing of equipment and distance to property lines. • Fire protection requirements that are greater or more stringent than in-house company or local codes and standards. In addition to codes and standards, there may be local regulations, protocols, and procedures required to assure timely approvals and acceptance at various stages of the design, construction, and operation of a new site or plant. Ask the following questions regarding local requirements: • Is there a requirement for approval by a local professional engineer for buildings, structures, foundations, and/or other designs? What is the approval schedule and specifics regarding the information that needs to be reviewed?

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• Is there a requirement for governmental approval of drawings and specifications, risk assessment, inspection of construction site activities, and/or inspection of equipment before startup approval is granted? • Are there zoning regulations that limit the use of property? This may have an impact on future intentions for the site. For example, are there limitations on temporary use of the site for stock piling waste material during the construction of the new site? Is part of the site not usable because of future local government plans to expand community housing in the surrounding area? • Are there limitations regarding the maximum height of structures such as buildings, flares, and towers? Are there local requirements for limiting the visibility of the site for community housing and/or the site property line? Are there limitations regarding the visibility of flare luminescence or nighttime site lighting? • What are the aircraft regulations regarding height limitations of structures and/or provision of warning lights at the site? Is the site within an airport glide path? • Are there specific language requirements that need to be considered regarding the communication of documents and information to various local authorities and inspectors? • Are there other quantitative or qualitative risk standards that will have to be met? Conducting an abbreviated risk assessment may be prudent to assure the ultimate acceptability of the site. • Do local regulations require any special security measures for buildings, roadways, and fencing? • Are there building codes that address earthquakes, fires, or hurricanes or typhoons?

3.5.2. Maps and Surveys Acquire maps and surveys of potential sites prior to visiting the sites including the following: • A large, overall map of the surrounding area showing adjacent towns, highways, railroads, airports, and harbors. • Detailed maps of the site area, including a topographical map with 1 to 2 foot (0.3 to 0.6 m) contours to provide good definition. • If available, maps showing the location of streams, ponds, marshes, steep slopes, buildings, or other structures on-site, and any present

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or future right-of-way requirements, underground sewers, pipelines, and old foundations. • Survey information that identifies foundations, monuments, benchmarks, and elevations related to standard base points and land elevations, and related to marine elevations if pertinent. • Aerial photographs of the entire site showing the following: —Surrounding community areas, town centers, malls and shopping centers —Sensitive populations such as schools, hospitals, day care facilities —Nearby industrial sites and transportation centers —Farms and agricultural centers —Environmentally sensitive areas —Location of services that may be subject to interference from a new site or may interfere with the communication or operation of your site. These may include radio, television, or microwave communication equipment.

3.6. Environmental Control Issues Once sites to be evaluated are chosen, acquire information concerning environmental regulations before site surveys are actually conducted. This information can provide the survey team with guidance on what to look for and what additional data to collect while at the site(s). This section outlines the specific information of interest prior to the site selection process. As discussed previously, a preliminary hazard analysis may also identify potential environmental concerns to consider when choosing a site and the land area required. If there are environmentally sensitive sites on the proposed plot or in the area around the site, it may be prudent to relocate the site to avoid costly environmental controls and permitting difficulties or increase the size of the site to permit more rigorous environmental control facilities.

Example A site is under consideration at a location where there is a known aquifer beneath the site. An environmental survey identified the need for additional wastewater treatment land area to accommodate more extensive treating and retention facilities. The topography is also an issue. The area is very hilly

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and will require costly civil work to control run off and retention of site rainwater. Based on this information, the site area must be expanded to accommodate the additional wastewater treating facilities and the additional land area required to allow good civil engineering design to prevent flooding. This same site has been found to contain Native American burial grounds. Although located on the purchased land, the burial grounds must be secured with a buffer area around them as required by local regulation. Since the burial grounds cannot be built upon, additional land area is required to accommodate the facilities needed for the new site. All these issues may not have been identified if the siting team had not included an environmental specialist that investigated local regulations regarding the burial grounds and aquifer.

Lesson

This example may seem overly simplified; however, there have been cases where projects were never built due to unanticipated limitations on how a selected site could be used.

Basic information is required at the site selection stage that may weigh into the decision to choose one site over another. The first step is to obtain copies of the federal, state, and local regulations. Determine if there is a requirement to have environmental system design plans approved by authorities. Determine if permits are required to operate the environmental systems and what the requirements are for acquiring a permit. Identify agencies that enforce the regulations. The enforcement agency can often be helpful in providing clarification of various requirements in the regulation. Acquire regulations on: • Air quality control • Wastewater volume limitations and quality of industrial discharge • Solid waste disposal • Noise level limitations • Flood levels • Luminosity levels

3.6.1. Air Quality Control In the United States, the Code of Federal Regulations (CFR Title 40) and the Environmental Protection Agency publications are resources concerning air

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quality regulations. Local consultants may be necessary to acquire codes and regulations and provide interpretation of the requirements in foreign locations. In foreign locations, it is also useful to investigate if there are any national technical groups with an interest in air quality control, similar to API for example, that may publish helpful data. The information that is needed during the planning stage of the site selection process regarding air quality control regulations follows: • Determine what materials are regulated regarding discharge to the atmosphere, specifically, the maximum discharge rates and quantities. Following is a list of materials that are regulated in the United States: —Particulate matter —Hydrocarbon vapors —Carbon monoxide (CO) —Nitrogen oxides (NOX) —Sulfur oxides (SOX) —Photochemical oxidants —Visible emissions —Odors • Determine if there are regulations regarding allowable industrial stack heights and the criteria needed to determine minimum heights. • Determine if there is any requirement for vapor recovery in storage tank filling and emptying, tank truck loading operations and what criteria established the requirement.

3.6.2. Wastewater Control Specific to wastewater quality control, some basic information required includes: • Is an environmental impact statement required? If so, specific information acquired during the site survey may help focus the issues of concern. • What are the regulations regarding storm water discharge without treatment? • What do the regulations specify regarding the level of treatment required for industrial wastewater? • What are the performance requirements for the treatment facility? Is there a requirement to submit treatment facility operating reports? What data needs to be reported?

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• Do the regulations specifying analytical methods to be used in determining the level of specific impurities in the effluent include hydrocarbon or toxic materials content? This is an operating cost issue.

3.6.3 Solid Waste Disposal In the United States, solid waste disposal is regulated by the Resource Conservation and Recovery Act (RCRA). Through RCRA, EPA has the framework to develop regulatory programs to manage solid waste, hazardous waste, and underground storage tanks. RCRA includes a system for controlling hazardous waste from its point of generation to its final disposal, encourages states to develop comprehensive waste management plans, and regulates certain underground storage tanks. This Act also establishes performance standards for new tanks and requires leak detection, prevention, and corrective action at underground storage tank sites. Clearly understanding the implications of RCRA or other applicable waste disposal regulations is important to site planning. Solid waste disposal handling needs may require additional facilities at one site compared with trucking only to an existing disposal facility at another site.

3.6.4. Noise Control Consideration of noise regulations at this stage is focused on the community sound level limits that may be exceeded due to noise from the site as well as noise due to increased truck traffic associated with the new site. Acquire existing and pending specific regulations and ordinances to determine if there are any community noise level limitations.

3.6.5. Flood Levels Many states and local areas have zoning restrictions designed to minimize potential damage from flooding. These regulations may limit the ability to construct a facility in a flood prone area or may restrict the type of equipment installed at certain elevations.

3.6.6. Luminosity Levels Light levels are also regulated by many states and localities. This may impact the size, height, and design of flare selected for a site.

4

Site Survey and Selection

Chapter 3 helped us to prepare for the site selection process. Now it is time to actually visit potential sites, gather data, and evaluate the options. Which site to select is rarely an easy decision. Each site will have advantages and disadvantages that are comprised of varying elements of safety, cost, and schedule. As in any major decision, carefully considering the options and focusing on both the short-term and long-term objectives will yield the best results. A project-specific checklist may be developed for use during data collection based on the Site Survey Data Requirement List provided in Appendix B. Once that data is compiled, the process of comparing the site attributes begins. This Chapter provides discussion around site features including topography, infrastructure, security, environment, and emergency response capability. These discussions identify desirable and undesirable features. These features may influence the capital cost, the life cycle cost, and the risk (financial, safety, environmental, and public concern) of a particular site. Balancing the costs and risks is a challenging effort with many potential outcomes depending on the differing weights that a company places on costs and various types of risks. At the end of the study, the site with the best cost to risk balance for that company’s values is chosen.

4.1. Information Required to Select a Site 4.1.1 Maps and Surveys Acquire maps and surveys of potential site areas prior to visiting the sites. Much of the detailed information, however, will need to be gathered during the site survey. The survey team can mark up maps with site-specific details to provide the quality of information needed for a thorough evaluation of each site. Refer to Section 3.5.2 for the types of maps and information desired. 33

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A survey of the surrounding area will be necessary to identify off-site exposure concerns. Make notes on an area map identifying the following types of existing and potential neighboring populations or facilities: • Town centers, malls and shopping centers, housing areas • Sensitive population centers such as schools, hospitals, day care centers • Nearby industrial sites and transportation centers • Farms and agricultural centers • Sewers, water mains, and storm drainage • Natural gas and other pipelines • Environmentally sensitive areas, such as wetlands • Future facilities that are in the planning stage, particularly if they may present an external exposure to your site. • Future population encroachment • Location of services that may be subject to interference from a new site or may interfere with the communication or operation of your site. These may include radio, television, or microwave communication equipment. • Points of national interest such as nuclear power plants, military bases, or major historical sites. • Note any specific zoning restrictions that may affect the new site. • Nearby facilities that could affect the new site. When selecting a site, an ideal choice would be one with no neighbors to minimize off-site risk potential. Sites such as this exist but seldom have the infrastructure required to efficiently run the site. From the off-site impact point of view, the decision focuses on the density of population surrounding the proposed site and the existence of any sensitive populations or areas. A site in a rural area is preferable over a site in a highly populated urban area. A rural site will not necessarily remain rural unless you have purchased the surrounding land. An alternate to starting with a rural site is to buy additional land as a buffer zone or to have the land adjacent to the plant zoned such that there is no residential housing or sensitive populations nearby.

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4.1.2. Topography, Terrain, and Soil Properties Utilize topographical maps. In addition to elevation changes, note aspects such as waterways and site terrain (sand, rock, marsh). A site with significant elevation changes may be a challenge to lay out. Gravity will take any liquid or heavy gas release and carry it downhill to the lower elevations of the site. On the other hand, gravity flow may be used to facilitate product transfer and reduce energy costs.

Example In Tacoa, Venezuela on December 19, 1982 an explosion blew the top off a large oil storage tank at the electricity company in Caracas, Venezuela. The oil in the tank caught fire and, eight hours later, boiled over. Topography played a key role in the events that followed the boilover of the tank. The tank sat on a steep hillside, which allowed for gravity feed to the equipment below. When the boilover occurred, the oil overflowed the tank dike. Firemen and spectators were caught in a downhill flow of burning oil. The incident resulted in 153 fatalities including 40 firefighters. [From Loss Prevention in the Process Industries 2E by F. P. Lees. Reprinted by permission of Elsevier Science Ltd., Lees 1996]

Lesson Consider topography in site selection and layout as it can have an impact on the potential consequences of an event. Also, although the phenomenon of boilover is rare, when it does occur, it can do so with significant consequences. Carefully consider the storage location of materials with the potential to boilover.

Terrain will influence the cost of construction. Dry, solid earth is less expensive to manipulate than rock or marshy areas. If blasting is anticipated, investigate if blasting will be allowed in the area, what restrictions if any, and how to obtain government permits. Investigate the soil properties to anticipate the need for remediation, document current contamination levels, and identify any potential problems with major foundations for structures and equipment. This may require taking a number of samples in various locations. The team will need to determine what the local experience has been with neighborhood structures or

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industrial facilities regarding soil load bearing, settlement, and need for piling. If there is a concern with spreader footings or heavy mobile equipment, conduct a preliminary soil investigation to determine the basic foundation requirements. Take soil samples to determine its potential corrosive properties to underground pipe. Collect enough soil samples to assess the need for, and potential extent of, remediation on the site. Soil investigation reports may be available from local authorities. The need for extensive piling can significantly increase the cost of a project. From a site selection point of few, the less piling needed, the better. Additionally, sites with low load bearing capacity may have a higher incidence of structures settling. This settling may lead to shifting of equipment, cracked equipment, and spreading flanges that may result in incidents. Review the location of local aquifers and water extraction points. These are sensitive features that may impact site selection and preparation. Acquire groundwater levels and area flooding history to ascertain whether protective dikes or spillways are necessary. A history of water levels from any existing water wells in the surrounding area up to 4 miles (6.4 km) away may be helpful in determining groundwater level history. Collect a sample of ground water at the site or from a nearby location if necessary, and test to determine the properties of the water. Properties such as high sulfates in groundwater can cause underground deterioration of foundations unless special concrete is used. Flooding is an issue in terms of potential property damage and operational downtime. Selecting a site without the potential for flooding is the first choice. An alternative is to identify grading and dikes to minimize potential impact and to layout the site with those operations not impacted by flooding in the areas subject to flooding.

Example A chemical site was being planned for construction in the Middle East. Two arid desert sites were being considered. One site was near a small town and was selected based on the use of the local industry and contractors for lower site construction costs. During the survey it was noted that the sand in the area was useful in making concrete. Contractors in the area use the local sand in building foundations and other masonry construction. The local contractor was required to make the appropriate quality assurance inspections of the materials used for the site foundation work.

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Years later, after construction was completed and the site was in operation, unusual settlement and degradation of the foundation rings under the storage tanks were found during inspection. The foundation settlement was believed to significantly increase the risk of leaks at the floor to shell seam, and potentially result in collapse of a tank. Samples of the concrete foundation and local sand were analyzed and found to contain a high salt content which interfered with the concrete curing process causing the foundations to weaken and crack. Nothing could be done to the existing foundations to arrest settlement therefore slip piles were installed at each tank to provide the added foundation support needed to arrest the settlement.

Lesson

The company did not analyze soil samples before the site was constructed. Although this would not likely have changed the location of the site, it may have provided insight regarding the selection of contractors or improved the quality control of the foundation activities during construction. The cost benefit of local concrete materials for the selected site may not have been as significant a factor had information regarding the sand quality been available during site selection.

4.1.3. Site Specific Meteorological and Geological Data Site-specific meteorological and seismic data will be required for a variety of activities including permitting, equipment design and layout, and construction of the new site. Identify the sources of data, indicate the span and dates of the recording period, and identify where the data was recorded in relation to the location of the new site. Meteorological data listed in the Site Survey Data Requirement List is available from various sources: local weather stations, local airports, and weather agencies including National Oceanographic and Atmospheric Administration (NOAA) Site impacts of meteorological conditions may impact project design as well as life cycle costs. Temperatures will have an impact on air-cooled heat exchangers and other heat exchange equipment efficiency and energy requirements. It will also have an impact on metallurgical requirements in severe cold climates. The location of the frost line will impact foundation and underground piping design. The prevailing wind direction will be used in siting potential release points downwind of potential ignition sources. The wind speed will translate

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into loading on large or tall structures such as buildings, pressure vessels, piping, storage tanks, air-cooled heat exchangers, cooling towers, and stacks. Additionally, the wind will serve to carry pollutants and potential releases downwind. Identifying potentially impacted areas and populations downwind may help determine whether or not a site is appropriate or if additional separation to these areas is advisable. Rainfall on the site will typically require water treatment. This may translate into the need for large water treatment facilities. Additionally, large amounts of rain in short periods as may be seen in the tropics and semi-tropics will impact the drainage design systems. Failure to address this issue could result in flooding of the site with potential operational, safety, and environmental impacts. Precipitation in the form of snow will translate into higher loadings on structural members requiring more costly, stronger, designs. One form or another of severe weather including significant rain or snowfalls, lightning storms, or tornadoes can occur almost anywhere. Consequently, all sites have a weather issue of some type. However, some sites are subject to additional weather threats such as hurricanes or typhoons along coastal areas. Selecting a site with the potential for a hurricane or typhoon will require greater site emergency preparedness, stronger structural design, and consideration of business interruptions due to storm watches, the storms themselves, and cleanup activities. Hurricanes or typhoons, as well as significant rainfalls, can lead to flooding concerns. Sites in low lying areas subject to flooding may require higher building and equipment elevations which may require significant amounts of landfill and additional structural support.

Example In 1998, an entire refinery was shut down for three months after being struck by Hurricane George. The hurricane left the entire site submerged by more than four feet (1.2 m) of salt water from the Gulf of Mexico. Although the hurricane was only a Category 2 storm, its slow movement subjected the refinery to 17 hours of high wind and rain. The storm surge overtopped the dikes built to protect the refinery, which is located close to the shore of the Gulf of Mexico. In all, 2,100 motors, 1,900 pumps, 800 instrument components, 280 turbines, and some 200 miscellaneous machinery items required replacement or extensive rebuilding. Newer control buildings and

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electrical substations sustained little or no damage as they had been built with their ground floors elevated approximately five feet (1.5 m) above ground (Marsh, 2001).

Lesson Consider meteorological and severe weather conditions in siting. Although these conditions cannot be controlled, appropriate siting and layout of critical equipment and structures may minimize the potential damage.

Seismic Data are available from various sources including the US Geological Survey (USGS), local regulatory authorities, and in the United States from zone maps in the International Building Code (IBC). The zone map provides an Earthquake zone number (1 indicating the lowest severity up to 4 indicating the highest severity). The zone number is a measure of the frequency and intensity of earthquake activity at a specific location. It is used in applying the IBC to develop the forces resulting from an earthquake for design of equipment and structures. Local building codes may have supplemental criteria to the IBC concerning earthquake design. Therefore, obtain a copy of the local building code as well as any state or local exceptions or additional requirements. The potential for seismic activity at the site may impact construction design and costs and may increase the potential for loss of containment incidents.

4.2. Transportation Issues 4.2.1. Product and Materials Handling The method by which raw materials and feedstock will be brought into the site and products, by-products, and waste will be removed from the site will be specific to a selected site. Portions of this information may be included in the project description discussed in section 3.1; however, specific data for each potential site must be evaluated. A transportation risk assessment may be warranted to consider the chemicals, volume, frequency, and risk of potential traffic accidents and chemical exposure on the surrounding community. The CCPS Guidelines for Chemical Transportation Risk Analysis (CCPS 1995, no.21) provides information on this topic.

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Example: There was a proposal to build a 60,000 bbl/day (9,600,000 l/day) onshore crude oil production facility with potential to increase to 100,000 bbl/day (16,000,000 l/day) in the future. Transportation options included transport of the crude oil by railroad or by a 100 mile (160 km) pipeline to the refinery. Initially, the pipeline was not considered a feasible alternative due to permit concerns considering the environmentally sensitive areas that the pipeline would traverse. A transportation risk assessment was conducted. The railroad option required 12 jumbo tank cars per hour every day of the year. The access to the site from the main line was via a single 10 mile (16 km) rail spur. On this same rail spur, transportation also included 3 additional trains with 28 cars of LPG. The risk assessment showed a significant risk of rail accidents and potential chemical consequences. A concern was the pressure on the operators to complete their tasks in the tight schedule of loading a train of 12 railcars every hour. These tasks included spotting the cars, performing pre-loading safety checks, loading, and performing post-loading safety checks. Additionally, the top loading of rail cars introduced personnel risks during loading. Given this risk level, the pipeline alternative was reconsidered. The routing of the pipeline around the environmentally sensitive areas was evaluated. Also, the pipeline route was carefully laid out through the neighboring farmland and away from populated areas. A transportation risk assessment was then conducted of this proposed pipeline layout to determine the risk on the environmentally sensitive areas and surrounding communities. The risk assessments were presented at the public enquiry. Eventually, the pipeline alternative was approved and permits granted.

Lesson Consider transportation risks during the site evaluation phase. Conducting a transportation risk analysis will provide a better understanding of the risk and the potential prevention and mitigation measures that may be required.

TRUCKS

Where trucks will be utilized for import and export of materials, obtain information regarding designated hazardous transportation routes, access roads, and connecting highways. Estimate probable traffic patterns during peak and off-peak loading and unloading hours to assess the impact on the

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road systems. The need to strengthen or build new site and/or public roads accessing the site may impact site selection. The routing of materials over public roads may also increase risks if traveled through populated and/or sensitive areas. A site where traffic routing minimizes this risk is desirable. Determine support facilities required. Will site plot space be required for a scale or is one commercially available? Is a vapor recovery system required for loading operations of volatile products? Obtain copies of local regulation regarding vapor recovery.

Example: A refinery was considering a change of process technology for production of a high-octane gasoline-blending component called alkylate. The present technology used a highly toxic catalyst (hydrofluoric acid) that has the potential for undesirable off-site exposure effects in the event of a large accidental release. A risk assessment study was performed and several risk reduction alternatives were identified. The risk assessment was specific to the transportation issues of this site and considered the life cycle of the process. One such risk reduction consideration was converting the HF alkylation process to sulfuric acid (H2SO4) alkylation. However, to make the conversion, sulfuric acid regeneration facilities needed to be provided. Two alternatives were considered. Alternative 1—Build on-site H2SO4 regeneration facilities Alternative 2—Use off-site H2SO4 regeneration facilities and bring in fresh acid and return spent acid by truck. Local regulations and local planning authorities eliminated the possibility of Alternative 1, building on-site regeneration facilities. Therefore, Alternative 2 was considered. Traffic routes for the increased truck traffic were evaluated. The number of trucks required included 900 fresh H2SO4 and 900 spent H2SO4 trucks per month. All truck route options required a substantial increase in truck traffic through the community area around the refinery. In comparison, the current process required 1 HF truck per month for acid make-up. Therefore, a risk assessment was conducted to determine the risk associated with the increased truck traffic to the community. As a result of the analysis, it was determined that the conversion to sulfuric acid and the associated increased truck traffic actually posed a higher

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risk to the community than the presence of the existing HF Alkylation with alternate risk reduction measures employed. Therefore the process change was not implemented and the alternate risk reduction measures were installed.

Lesson Process hazard analysis conducted in supporting the siting decision must consider transportation risks as well as process unit risks. The combined risk may prompt a different risk management decision than considering the process risk alone.

PIPELINES

Where pipelines will be utilized for product transfer or materials delivery, determine the location of pipeline corridors and options for routing the pipeline into the site. Record the conditions of the pipeline including the line length on the site, pipeline diameter, operating pressure and temperature of the pipeline, and batch handling arrangements. If an existing pipeline is considered for reuse, consider the overall pipeline suitability for purpose (based on process conditions). Note whether the site terrain will allow burying of pipelines or require pipelines to be laid aboveground. Determine whether cathodic protection is required and if it will interfere with other systems nearby. The pipeline routing will impact the site selection in terms of layout of site equipment, risks associated with pipeline leaks, and potential security concerns. RAILROAD

Where product shipments are to be made by railroad tank car, are rail facilities available both leading to and on the site to accommodate this need? If not, consider the possible routing and cost of rail facilities as well as clearances required by regulation from operating facilities. As in road transportation, assess the risks of routing toxic or pressurized flammable materials by rail through the surrounding community. Additionally, the potential impact of new or increased rail traffic on the surrounding traffic patterns, emergency response routes, and noise levels may make one site more desirable than another in terms of ease and probability of success of getting permits for new rail lines. Railway issues that may require clarification with the railroad company include: • Train length with respect to distance between crossings and the potential impact on emergency response vehicle traffic

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• Condition of the railroad • Increased rail traffic • Emergency firefighting access to the railroad lines in and near the site

Example A chemical plant was constructed in 1916 on the East Coast adjacent to a small town. The location was ideal as the chemical plant was bordered on the north by a navigable river, and on the south by the railroad right-of-way. As the town grew, it expanded to the other side of the railroad tracks. Now the railroad dissects the town with only four street crossings that cross the tracks and connect both sides of town. Today expanded community housing, the school, daycare centers and industry all share the land on the north side of the tracks bordered by the river. To the south of the tracks are the town center, emergency services, and access to the main highways. The trains utilizing this railroad track are 60 to 100 cars long. Trains use the tracks frequently to make scheduled freight car drop-offs and pickups during which the four street crossings may be blocked for up to 15 minutes at a time. No access (including emergency access) to the north side of town and industry is available during the period when the train is blocking the road crossings. This situation continued for many years. Finally, the town considered options including a bridge in place of one of the railroad crossings. The bridge now provides a single point access to the north side of town and industry when the train is blocking the remaining rail crossings.

Lesson

Transportation routes and increased traffic on them may present a risk to the community and to the chemical or refinery site by limiting access and egress. Ensure that sufficient emergency response access will be available after the addition of roads and railways for the new site and take into account the increased traffic on these road and railways.

Local requirements or practices regarding methods of loading and measuring cargo for hazardous products such as LPG, gasoline, light fuel oils, and toxic chemicals may impact spacing and location of these facilities from property lines and other on-site facilities.

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MARINE FACILITIES

Where existing marine facilities are to be utilized, obtain a detailed description of available port facilities. Research specific port requirements such as operating hours, tugboat escort requirements, and hazardous cargo restrictions that may impact operational and safety issues. The channel and harbor must be of sufficient width and depth to safely accommodate the ships anticipated for the site or modifications may be necessary. Investigate severe weather impacts on the marine facilities to determine their potential impact on safe mooring and product transfer. Also, investigate the availability of mooring sites at the port. Demurrage associated with waiting to moor, waiting out a storm or frequent cessation of product transfer may make a site undesirable. Another marine consideration is the availability of, or requirement to provide, on-site support services such as for bunkering, deballasting, cargo tank cleaning, and ship repairs.

4.2.2. Special Transportation Requirements During the construction phase of the project, it may be necessary to transport large heavy loads to the site. For sites where heavy or large loads will be brought in by water, determine if the site port facilities can support the maximum weight and size of the cargo to be transferred, if they have floating cranes to transfer the material, and if they require special unloading ramps? Where heavy or large equipment are anticipated to be brought in by truck or railroad, will there be enough highway and railroad clearance, including bridge and tunnel clearances, sufficient to allow passage of the vehicles?

4.3. Utilities The existence of utility infrastructure at a proposed site will reduce project cost. However, before a project proceeds, verify that the quality, quantity, and reliability of that utility is adequate for the project needs. Specific data of interest is listed in the Site Selection Data Requirements List in Appendix B. The availability and reliability of the existing utilities may be critical to facilitate a safe plant shutdown in an emergency situation.

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4.3.1 Water Supply Determine possible sources of drinking water, boiler feed water, firewater, closed cooling water makeup, and service water at the site. Check availability, reliability, and cost of municipal water, river water, and well water. If these supplies are not available at the site, additional plot space may be required to provide storage facilities. Note restrictions regarding location, quantity, quality, and temperature of warm cooling water returns. These requirements may lead to the need for additional heat exchange equipment that translates into more plot space. Consider design problems that might be encountered with rights-of-way, water intake stations, icing, or suction conditions. Review requirements imposed by environmental codes.

Example An industrial complex was being considered for the location of a new process plant. The complex was located along the coast, had marine access and facilities and provided various utilities including water for cooling water, firewater, and boiler feed water. One of the attractions advertised by the complex was the cost reduction associated with the elimination of independent firewater tanks and pumping systems. This firewater supply met the 150 psig (1000 kpag) minimum firewater requirement at the battery limit. The complex location was selected and the cost reduction was assumed in the project funding. During early construction and design of the new process plant a followup site survey was conducted. During the survey it was noticed that most of the other complex occupants had an independent firewater tank and firewater pumps. On further discussion, it was determined that the sites within the complex often competed for water demand from the pipeline during certain periods. During these periods, the water pipeline pressure dropped and sufficient water supply might not be available for hours. Further, even at normal water demand, the pressure often dropped below 100 psig (690 kpag). As a result, firewater and boiler feed water tanks as well as the pumping systems were added to the project requiring the acquisition of additional funds.

Lesson

Analyze site features in sufficient detail during the site selection process to accurately determine what the site does provide and what additional facilities will be required.

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4.3.2 Steam Supply Steam-generating facilities include boilers, boiler feed water, condensate collection and handling, boiler blow-down, piping, waste heat recovery, control, and environmental protection systems. Determine the codes, rules, regulations, and standards governing the construction and operation of steamgenerating facilities and acquire copies. Are there adjacent sites, such as public utilities or municipal installations, from which steam could be purchased during shutdowns or emergencies? Provide details regarding pressures available, reliability, and variable and fixed costs. The information above will primarily provide an understanding of the economics for steam generation at one site versus another. From a safe siting viewpoint, however, the reliability of the steam generation facilities does play a role in the reliability and safety of the future operating site.

4.3.3 Fuel Determine the availability, reliability, supply points, heating values, costs, and analysis of fuel commonly used in the area. Include details of supply facilities, pressures, temperatures, and fuel specifications, if available. Identify and review state, local, and national environmental codes (if any) regarding fuel specifications. Also, consider the future use of fuel supplies from remote locations, including substitute fuels such as coal, natural gas, and others. Once again, the evaluation of fuel supply has a large economic component. It also impacts site safety in terms of providing a reliable supply to minimize unplanned shutdowns. Consider the needed fuel supply facilities (storage tanks, pipelines, and unloading facilities) in terms of plot space required and location. A specific area of interest where fuel is imported to or exported from the site is the risk posed by the metering facilities.

Example A facility was being proposed in a remote semi-tropical area. Fuel gas (methane through pentane) and nitrogen were being supplied by an outside source via pipeline. Metering stations were located outside the new site property line and owned and controlled by the supplier.

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To secure the use of the utilities, the company and supplier agreed to terms early in the project life, and a location and tie-ins for the meters were fixed. Due to the high reliability of the supplied fuel gas, back-up power generation facilities were minimized resulting in a significant project cost reduction. The probability of failure within a fuel gas metering facility is relatively low. There is, however, exposure risk to the Fuel Gas Metering facility from the new site process area. The consequence of losing the fuel supply to the electrical generation equipment is substantial. It was decided that the risk of this loss was not acceptable and should be mitigated. Relocating equipment within the new site was not feasible due to the minimal land area available and other concerns resulting from different equipment arrangements. Ideally, locating the metering stations further away from the new site was feasible before the meters were installed, however, the cost of relocating this already installed equipment was substantial. As a result, the risk reduction option chosen was to add the back-up power generation facilities back into the project. The cost of this later addition was substantially higher that the costs would have been to site the metering station in a different location prior to installation.

Lesson

Understanding the availability and reliability of fuel gas and other utilities during site selection and their potential vulnerabilities may avoid late design changes to add costly utility back-up facilities.

4.4. Electrical and Communications Systems 4.4.1. Electrical Systems Contact the local electrical utility to determine if they can provide an adequate and reliable power supply to the site. Note the location of the incoming supply to the site as this will impact siting and layout. If commercially available power is not adequate, site plot space will be required for power generation facilities.

Example A company was planning to build a process in the Midwest in an area subject to freezing temperatures and ice storms. The local utility stated that they were able to supply the quantity of power required from two independ-

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ent power plants. Based on this supply and reliability, the company decided to utilize fully purchased power and not construct an on-site power generation facility. This resulted in significant cost savings to the project. Two years after the plant was constructed, the area experienced an ice storm that caused loss of total power. Investigation showed that the lines from the power plants to the process plant were both located above ground and ran in parallel, adjacent paths the last 1500 ft (460 m). This path ran along the river and therefore often subjected to the icing effects during a cold winter rain or snow. A hazard analysis might have identified this common cause failure and led to alternate siting or routing.

Lesson Analysis of utility reliability should include a thorough review of all utility supplies to ensure that they are fully redundant and independent such that a single cause will not lead to failure in both supplies.

4.4.2. Communications Systems Conduct an assessment of site communication requirements. The site occupants and their needs will dictate the equipment required. A small installation may have much smaller and simpler needs than a site housing engineering offices. When building on a greenfield site, there may be no communication facilities available. Thus all infrastructure would have to be developed. In an existing site, there may be infrastructure in place; however, it may require expansion or upgrading. Ensure space is available on the site to allow for communication line right-of-ways either above or below grade. The prime issue regarding communication is defining the requirements for safety and emergency response. Understanding the assets and limitations of available communications systems will provide a sound basis for establishing the communication links needed during construction and future operations for emergency response and notification. Following are the types of issues that help evaluate the effectiveness of communication systems available at a potential site. TELEPHONE SYSTEMS

Describe the local telephone system (manual or automatic), length of time required for installation, compatibility, and regulations for a site-owned

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exchange switchboard. What arrangements can be made for tie lines or for long distance phone calls? INTERNET SYSTEM

Determine what internet communication support is available: phone lines, broadband, cable, ISDN. These systems may be used to support e-mail, and current or future e-commerce applications. MICROWAVE COMMUNICATIONS

If telephone and internet are not available or are not reliable, microwave systems may be an alternative. This requires substantial initial investment for the installation of towers and other equipment. RADIO COMMUNICATIONS

For two-way radio communications, determine the authority responsible for control of local in-plant systems, local regulations, frequencies and types of transmission permissible, power sources, and licenses required. Determine what other radio frequencies are in use in the vicinity and the possibility of instrumentation interference. What arrangements can be made for company communications by radio to other parts of the country? MAIL SYSTEM

Determine the location of the nearest post office and the major mail sorting facility, as well as the frequency and source of mail pickups and deliveries.

4.5. Environmental Controls As mentioned in Chapter 3, toxic materials may be released to the atmosphere, ground, or waterways. These releases may be modeled to determine the potential consequences and risks on neighboring environmentally sensitive areas and surrounding communities. Consider this in site selection as these potential exposures may affect the permitting process and the need for future costly prevention and mitigation systems to address the potential of releases to the environment.

4.5.1. Wastewater Quality Control As stated in Chapter 3, acquire national, state, and local regulations concerned with industrial wastewater discharge and any volume limitations.

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Firewater runoff may also be a siting consideration if this volume must be addressed as wastewater. Define any national, state, or local regulations controlling discharge quality. A site where it is permissible to discharge clean storm water without treatment will require smaller treatment facilities, hence less plot space. Successful wastewater quality control is highly dependent on the unique features at any particular site location. Questions to ask in order to develop a thorough understanding of the potential costs and problems associated with a particular site regarding wastewater quality control are provided in the Site Survey Data Requirement List provided in Appendix B. Local requirements in terms of quantity, quality, and permitting may rule out a proposed site. Assess general governmental trends regarding wastewater control. If there is any indication that existing regulations will become more restrictive, or that new regulations will be adopted, obtain a forecast or timetable. This may impact future site expansions. With respect to the site, identify the existence and the location of environmentally sensitive areas. A site surrounded by sensitive areas downstream of its water effluent may not be as desirable as one without these areas.

4.5.2. Air Quality Control Air quality control regulations may impact the site selection process. National, state, and local regulations may control the discharge of sulfur oxides, particulate matter, carbon monoxide, photochemical oxidants, hydrocarbons, nitrogen oxides, other applicable chemicals, and odors. This may impact the ability of a site to be located in a specific area as well as the separation distances from the site to the surrounding areas. What is the general trend regarding air quality control? Are there any indications that existing regulations will be tightened or that new regulations will be adopted where there are none at the present time? This may reduce the opportunity for future site expansions. In relation to the facility site, what are the locations and proximity of residential areas, farming areas, hospitals and health resorts, business areas, industrial areas, public parks, and airports? Adequately separate the site from these areas to reduce risk of off-site impacts as well as nuisance odors. Topographical features, such as hills or valleys, can effect dispersion of air pollutants and should be considered in site selection.

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4.5.3 Sanitary Sewage Collection and Treatment Obtain regulations regarding collection and treatment of sanitary sewage and consider them in site selection. If public facilities are not available, adequate, or able to be used, then site facilities will need to be provided. This will have an impact on plot space and project cost.

4.5.4. Noise and Luminosity Level Design Limitations The site survey team should collect current day and night noise level data in the surrounding areas. This will aid in determining if appropriate noise levels will be achievable at reasonable cost to the new site or if consideration of an alternate site is warranted. Sound waves travel through most materials. The typical concern is sound traveling through air to the adjacent community. Sound may also be transmitted through the earth, specifically along water tables and subterranean rock formations, causing noise concerns in unexpected places and great distances away. Luminosity is also a consideration for plant siting. The light levels produced by the general site lighting may be regulated either in terms of level or line-of-site visibility. Siting may take advantage of set back from the fence line, hills, or foliage to block the light. Specific pieces of equipment, such as the flare, may be impacted by luminosity requirements. Luminosity requirements may impact the height of the flare or necessitate using a ground flare design that will require greater plot space and siting considerations.

4.6. Fire, Safety, and Security The site selection should consider the availability and adequacy of existing local emergency response capabilities including firefighting, rescue, site security, police, and medical capable of handling the hazards associated with the site operations. If local capabilities are considered, are they available all day, every day? The opportunity to share response personnel and equipment through mutual aid arrangements will reduce the facilities required on each individual site. Do local regulations require the site provision of emergency response facilities or the use of local emergency response teams?

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Are there any governmental or local requirements for medical facilities or ambulance service? Inspect the area within a reasonable radius of the site and report on the availability of first aid facilities, hospitals, burn centers, doctors, and medical examination laboratories. Does a mutual aid emergency organization exist, and is there a local radio system linking ambulance services with hospitals or other medical facilities? The availability of adequate medical facilities, or lack thereof, may impact site selection. Where adequate facilities are not available, provisions for emergency response use of helicopters may be an alternative that would require plot space for the helipad and the helicopter’s safe approach free of overhead lines and tall structures. There are numerous site attributes that may impact security. Many of these features do not act as a positive or negative in the site selection process, but will require consideration during the site layout process. At the site selection stage, the concern is to assure adequate site plot space is provided to allow flexibility in the placement and control of site access points, safe routing of transportation corridors, and provision of reliable utilities. • An additional consideration is that toxic releases, fires, and explosions may also be due to sabotage or a terrorist action. The impact of these events should be considered in the preliminary hazard analysis or a security vulnerability analysis and in siting of the facility. • Transportation of materials to and from the plant may provide access for undesired persons or materials to enter the site or for theft of materials. Controlling the access and routing of transportation corridors away from highly occupied buildings and critical facilities will minimize these risks. • Railway sidings may traverse site property but may be under the ownership of a railway company. This minimizes the opportunity to control the access, personnel, and materials that are within the site property. • Piers, wharves, and shorelines may be difficult areas to control access due to the limited personnel attending these areas, the separation from the remainder of the site, and the fluctuating river or tidal levels. • Utilities that are provided from a single source reduce the reliability in a sabotage scenario given the ability to significantly impact, or shut

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down, plant production by interfering with a single power feed or water intake. • Sites with dense development immediately adjacent to the perimeter may provide more challenges in controlling access than those with a buffer zone around the site. • The ease by which a site can be seen and identified from a major transportation route may increase the probability that it is randomly selected for sabotage. • The proximity of a site to major population areas may increase the probability of potential sabotage from outside sources.

4.7. Site Features 4.7.1. Personnel The long-term safety and operability of the site is dependent on the quality and capability of the support staff needed to maintain and operate the site. If these resources are not available close to the site, then bringing in quality personnel and contractors will need to be factored into the site selection process. It is necessary to determine the availability of local contractors or personnel for handling day-to-day site maintenance and for supplying special crews for major shutdowns. The craftsperson qualifications, experience level, training, equipment, and tools that local contractors can supply must be determined. For example, are code-certified welders available or are personnel available to become operators. Obtain information on the educational level of the local population, as this level will affect the training facilities to be incorporated into the site. It will also have bearing on the sophistication of the instrument and control equipment to be selected for the facility.

Example Several international locations were being considered for a lubrication oil blending facility. The facility’s primarily purpose was to supply an increasing international demand in automotive lube products. Locations were considered in three countries. Each country site was evaluated to determine

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the level of education and capability of the local work force. For two of the countries, the typical current lube plant design was used as a template for the new site design. It included a DCS based control system and automated blending and packaging facilities utilizing current technology. For the third country, it was decided that using the current technology for a lube blending plant would not be practical given the skill base at the site. A less automated design, providing the same level of safety, was chosen to be the best alternative for this location to match the capabilities of the local work force.

Lesson Consider human factors issues in site selection and plant design.

4.7.2. Housing When a remote site is under consideration, investigate the surrounding area to determine the availability of housing and amenities for permanent personnel. In remote locations where company housing is provided, finding a suitable location for company housing is as important an issue as finding a suitable location for the new site. Temporary housing may also be required during the construction phase to support the surge in manpower requirements. If the temporary housing is to be located on the site, consider the separation distances between temporary facilities, construction activities, and plant start-up. Site selection may be influenced by the availability of transportation to the site, schools, shops, and recreational facilities.

4.7.3. Site Support Facilities To assess the advantages of one site location versus another, inspect local shops, service stations, garages, and other industrial facilities. This will help to determine if site maintenance activities can be handled on a contract basis or if facilities must be provided within the site. Services inspected include the types of construction equipment that can be rented or contracted locally, such as cranes, scaffolding, heavy trucks and lowboys, concrete mixers, temporary electric generators, and welding machines. It is important during this inspection to assess the quality of workmanship and consistent quality of work product to assure that the local services will meet the expectations of the new site.

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Construction activities typically include provision of trailers, laydown yards, and welding areas to name a few. Location of occupied buildings should be considered using API RP 752 and CCPS Guidelines for Evaluating Process Plant Buildings for External Explosions and Fires. Laydown yards should be located such that traffic will not be routed through sensitive plant areas. Areas involving hot work should be located so as not to be a potential ignition source to operating process units. Review the capability of local sources for providing maintenance and repair parts, materials, equipment, and supplies. Determine restrictions, if any, on importation of such parts and materials. Determine delivery times and possible causes of delays. Recommend a plan for site warehousing of materials, supplies, and spare parts.

4.8. Multi-Chapter Example In order to illustrate the progression of a project through site selection to major facility layout and eventually to individual equipment spacing, the following example will be carried through Chapters 4, 5, and 6.

Example Your company decides to build a new petrochemical site at an existing complex. The new site will include: • Process Plants —Ethylene —Low Pressure Polyethylene —Ethylene Glycol • Pelletizing and packaging facilities • Offsites —Flare —Ethylene Feed Pipeline —Tankage —Warehouses —Control room

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—Cooling tower —Port facilities for transport of finished products The company planners have identified three existing locations with comparable project viability economics. Initial descriptions of these locations are as follows. Location 1 – This petrochemical complex is situated in an inland location with river access. There is land at the complex edge that is a level elevation with no flooding potential. This complex is located in the middle of farm country with no population centers nearby. Location 2 – This petrochemical complex was once in farm country but the nearby city has grown and now surrounds the complex. There is dense population immediately adjacent to the complex. The complex has river access. There is plot space available. Location 3 – The petrochemical complex is located in an industrial complex well separated from residential or urban population centers. It has a marine facility. There is property adjacent to the complex but it is a significantly sloped site. A site selection team is assembled including: • Process engineering to provide details of the unit temperatures, pressures, chemicals involved • Civil and marine engineering to provide insight on structural issues and marine facilities • Process safety engineers and fire protection engineers to ensure inherently safer design considerations are addressed • Environmental engineering to ensure environmental issues are addressed in site selection • A representative from the local facility to ensure the local perspective is provided • A project representative to address cost and schedule issues This team completes its task of gathering detailed information on each potential location. The process engineer and process safety engineer make an initial report. Based on their best understanding of the process units design as they are currently planned, there are both fire and vapor cloud explosion potentials. The fire hazard area would be within the site boundaries; however, the 1-psi (6.9 kpa) explosion overpressure contour extends 900 feet (270 m) from the edge of the process unit. They also identify that

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ethylene oxide (EO) will be produced as an intermediate stream in the ethylene glycol process unit. Although this is an inherently safer design since the EO is contained within the process and does not have to be stored in quantity, there is the possibility for loss of containment in the unit piping containing EO. Ethylene oxide has a long-term exposure limit of 5 ppm. A drawing of each location and summary of this information gathered on each location is provided as follows.

Location 1 The petrochemical complex is located in farm country with the nearest population center, a rural town, located 7 miles (11 km) away. The site with ample plot space is located at the edge of the existing complex. It is level and able to support the plant structures without significant piling requirements. The site is within the 100-year flood zone but is well outside of the 50- and 10-year flood zones. The process safety engineer estimates that the off-site risk will be low given the location in farm country with the nearest farmhouse 1-mile (1.6 km) distant. The environmental engineer has not identified any local conditions or regulations that may cause concern for the project. There is a river access but further investigation has shown that current facilities are designed for small barges. The civil/marine engineer has identified that the current channel is neither deep enough nor wide enough to permit safe berthing of the size vessel required for economic transport of the product. The project engineer has researched costs for widening and dredging the channel and, while it is feasible, the cost is significant and added time in the schedule would be required.

Figure 4-1. Proposed Location 1

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Guidelines for Facility Siting and Layout

The site available in this complex has adequate plot space and is located near the edge of the existing complex between the existing flare and the property line. There are no flooding concerns at this location and the plot space is level and able to support plant structures without significant piling requirements. Houses are located 700 ft (210 m) away and an elementary school is located 1600 ft (490 m) from the property line. The proximity of these populations causes the process safety engineer to estimate the risk as being relatively high. The environmental engineer has raised the concern that permitting is becoming more restricted in this local area and he thinks the local council will likely require additional environmental control measures to reduce project air and noise emissions. The complex has a dock on the river with adequate channel depth and width to safely berth the size vessel required.

Figure 4-2. Proposed Location 2

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Location 3 The petrochemical complex is located within an industrial complex that is 17 miles (27 km) from the nearest town. The proposed location is between the existing chemical plant and a fertilizer unit. There is no separation between sites – just a fence. The complex has access to the marine facilities that are designed to safely accommodate ships larger than those proposed. The proposed site is one of the last ones remaining in the complex. It has a significant slope and has a dry creek bed that turns into a torrent when heavy rains run off the hillsides. The process safety engineer estimates the risk as being relatively low since the surrounding population is industrial and it is located away from the nearest town. The environmental engineer has identified no concerns with permits or sensitive areas but is concerned with water treatment facilities given the runoff into the location. The civil/marine engineer is pleased with the marine facilities but concerned with the amount of site preparation required to address the steep slope on the site. The cost engineer is concerned that addressing the issues associated with the slope will add to the cost of the project.

Figure 4-3. Proposed Location 3

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In a perfect world, the site selection team would have a choice of sites with ample real estate, adequate infrastructure, and no surrounding populations. However, the more typical situation is that the site selection team is faced with a difficult choice considering the trade offs of each location. The site selection team considers each site in turn. The specific positive and negative aspects of each site are presented in Table 4-1. Location 1 seems best from the safety point of view but may not be economically feasible with the river port concerns. Location 2 has residential areas and a sensitive population (an elementary school) nearby and, thus, poses a significant concern from the risk of vapor cloud explosions. Location 3 has no residential neighbors as it is located in an industrial complex and has adequate marine facilities; however, the site is challenging due to the steep slope. Considering all the locations, the team eliminates Location 2 due to concerns of risk on the surrounding populations. Locations 1 and 3 both have attributes that will add to project cost: marine facilities and the steep slope, respectively. The selection team recommends Location 3 based on an estimation that the site slope issues will be easier to control since they are on the site property, will be easier to engineer, and will likely cost less in the end to address. TABLE 4-1 Location Comparison Location 1

Location 2

Location 3

Plot space

Ample

Adequate

Adequate

Marine facilities

Inadequate

Adequate

Adequate

Estimated cost to modify site

Highest

Average

Above average

Distance to sensitive populations

1 mile

700 ft (210 m) 17 miles (27 km) (residence); 1600 ft (490 m)(school)

Permitting Issues

Small

Restricted

No Concerns

Potential flooding

100-year flood

None

Intermittent creek bed flooding

Potential off-site risk

Low

High

Low

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Lesson

61

Selecting a site includes consideration of many specialized areas. The selection team must include personnel that can adequately address all of these areas. Typically the proposed locations will include a mix of both positive and negative attributes from the viewpoints of risk (safety, environmental, financial, and public concern) and both capital and life cycle cost. The challenge is in balancing all of these considerations to choose the most appropriate location.

6

Equipment Layout and Spacing

The previous chapters have described how to select a site and lay out the major building blocks of process, utilities, OSBL, and buildings. Now it is time to lay out the individual pieces of equipment within the process units. Data from a major property insurance broker highlight the importance of considering fire and explosion events (see Table 6-1) (Marsh 2001). The layout and spacing of equipment can reduce potential fire and explosion impacts (see Table 6-2 on the following page). As Tables 6-1 and 6-2 illustrate, significant losses are possible. The process safety goals of layout are to design a workplace that will minimize the risk of injuries, environmental damage, overall property damage, and related business interruption resulting from potential toxic releases, fires, and explosions. The goals of the capital project team are to design and build the new unit within cost and schedule constraints. The challenge is to balance all of the goals: health, safety, environmental, cost, and schedule while keeping in mind the lifecycle of the unit and the operational goals.

TABLE 6-1 Property Losses by Type of Event Property Losses Exceeding $150 Million between 1970 and 1999 Numbers of Losses by Type of Event Refineries

Petrochemical Plants

Total

Percent

Explosions including vapor cloud

57

65

122

51

Fire

60

27

87

37

Mechanical breakdown

4

9

13

6

Other

7

7

14

6

236

100

Total

101

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TABLE 6.2 Property Losses by Type of Equipment Property Losses Exceeding $150 million Between 1970 and 1999 Numbers of Losses by Type of Equipment Refineries

Petrochemical Plants

Vessels and columns

25

23

48

21

Piping

25

5

30

13

22

22

10

Reactors

Total

Percent

Tankage

15

7

22

10

Pumps and compressors

11

4

15

6

5

4

9

4

42

42

Furnaces Other Total

84

36

230

100

6.1. Spacing Tables Typical separation distances between various elements in open-air process facilities are cited throughout this chapter and are provided in the Appendix A Tables. These distances are based on historical and current data from refining, petrochemical, chemical, and insurance sectors. The data were developed based on experience and engineering judgment (not always on calculations) and were updated based on incident learnings. Such numbers are frequently used in industry and are included in industry codes and practices. The separation distances cited are based on potential fire consequences. Highly reactive and exotic chemicals, such as alkyls or hydrazine, may require greater spacing or protection. Explosion concerns will also require further analysis and possibly increased spacing to meet specific design goals and to limit explosion damage. The separation distances in Appendix A and Chapters 5 and 6 are typical distances based on a review of the above data and were not arrived at by a statistical analysis of this data. Frequently the data offered a range of numbers from which a representative value was chosen. These typical separation distances assume a minimal level of site fire protection such as fire hydrants, manual firefighting capabilities, and adequate drainage to prevent flooding during a major firefighting effort. Dis-

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tances may be reduced or increased based on risk analysis of site-specific conditions or when additional fire protection, safety measures, or other layers of protection are implemented. Fire protection measures include: fireproofing, automatic water-spray systems, fire detection systems, emergency shutdown systems, and mobile firefighting equipment. Utilize consequence analysis of potential fire, explosion, and toxic impacts to determine the adequacy of substituting additional layers of protection for spacing. As stated in previous chapters, applicable codes, standards, and local regulations should be researched. If they contain more stringent spacing requirements than those quoted in these Guidelines, then they take precedence.

6.2. General Certain siting and layout guidelines apply to the entire site and have been discussed previously but are worth repeating with respect to unit layout. • Provide firefighting access from at least two directions in a path that does not require crossing an adjacent unit. Accessways should be provided at least every 200 ft (61 m). An accessway should be at least 20 ft (6 m) wide and should not pass under pipeways, equipment, or other structures. These will serve as firebreaks and permit fire fighters to safely approach a process fire from two directions with 100 ft (30 m) lengths of hose connected to hydrants located at accessways. • Consider the electrical area classification which is based on the chemicals handled in the surrounding area. Nonelectrical ignition sources may be included in the risk analysis for purposes of separating ignition sources from potential releases. • Determine if the operation will be single train or multitrain. Where units are shut down for maintenance independently, separate them from each other to permit the safe performance of maintenance work. • Provide access for maintenance by allowing clearance above, below, and between equipment. Locate equipment subject to frequent maintenance and cleaning to provide ease of access. Consider lifting arrangements for pumps, heavy valves, and other equipment in equipment layout. • Lay out equipment groups with like characteristics together. Taking this approach allows equipment posing a similar risk to be located

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together while being separated from other types of risks (such as locating all the high temperature pumps handling flammables in one group separated from a group of vessels). • Consider the drainage of the plot in laying out the unit. When laying out the unit, locate vessels or equipment with the potential to accidentally release large inventories of flammable liquids so as to drain away from and not pool under process equipment, means of egress, or in areas that could cause significant downtime if the liquid was burning. (An example of a poor layout might be locating a catch basin under the main power and control cable trunk for the unit.)

6.3. Single- and Multilevel Structures When laying out process unit equipment, it is preferable to do so with all equipment located at grade on a level plot. This may minimize the complexity of firefighting, potential explosion severity, and will facilitate drainage design and emergency egress. In some cases, process unit equipment is located on levels above grade for reasons of limited plot space, gravity feed, or need for equipment proximity. Where equipment is located on an elevated level, provide drainage to contain and divert any releases such that they do not pool under equipment or spill down from elevated levels to the levels below. The use of solid decking to prevent uncontrolled drainage from upper levels must be balanced with concern of minimizing confinement to reduce potential explosion overpressures as discussed in Section 6.5. One way to reduce confinement is to use drain pans directly under equipment and open grating in all other areas. Another design is a skid-mounted design. This design offers the ability to construct most of the unit off site, haul it in on skids, and make the last few connections on site thus saving time and money. The safety and environmental challenge with skid-mounted designs is that the overall width and length are limited which increases the need to trade spacing for reduced cost. This, combined with the additional aspect that the skids are often installed on top of each other, can produce a process unit that is the opposite of that preferable, single elevation layout described in the first paragraph of this section. The potential solution here is diligence in layout and design: adhering to company layout and spacing guidelines, utilizing risk analysis to consider alternatives, and providing additional layers of protection where warranted.

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The spacing values provided in Appendix A are for horizontal distances between equipment. Where equipment is located on multiple levels, determine the vertical spacing based on firefighting and personnel safety considerations.

6.4. Enclosed Process Units Process units may be totally enclosed in buildings or structures due to the climate or the toxicity of the materials being handled. The spacing tables should not be used for enclosed process units. Spacing should be based on hazard and risk analysis.

6.5. Layout and Spacing to Minimize Vapor Cloud Explosion Effects Explosion effects are significantly influenced by the confinement and congestion in the area of a vapor cloud. Confinement refers to the installation of solid floors, walls, or rows of equipment that effectively act as walls. Congestion is a combination of the amount and proximity of obstacles (vessels, pumps, or piping) that are included in an area. Minimizing the confinement and congestion will serve to minimize the potential explosion effects. Consider the following list when there is a potential for vapor cloud explosions (WBE, 1998). • Separating groups of process equipment (such as a pump row, a bank of exchangers, or a cluster of small vessels) from one another within a process unit may minimize the severity of a vapor cloud explosion. This separation distance should be 15 ft (4.6 m) or greater. This also applies to separating large vertical and horizontal vessels by one or more diameters from each other and from walls. • Avoid repeated obstacle patterns with close spacing, such as rows of heat exchangers, as this increases congestion. • Avoid long, narrow runs of semi-enclosed spaces (such as a corridor with equipment spaced close together on either side and a nearly solid deck of piping above). This geometry can increase the intensity of a vapor cloud explosion.

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• Make the spacing of stacked piping, such as multi-level pipeways, as large as possible. Allow as much unobstructed area of the layers both horizontally and vertically as possible. • Eliminate solid decks wherever possible in favor of metal grating or light weight metal panels. If the solid decking cannot be avoided, elevate the deck to at least three times the height of the vapor cloud that might accumulate beneath it. As a rule of thumb, a deck height of 45 ft (14 m) is sufficiently high for most applications. • If possible, do not enclose process units or portions of units. If enclosures are used, minimize confinement and congestion within enclosures, consider damage limiting construction, use the appropriate electrical area classification, eliminate ignition sources, and evaluate ventilation (to dilute flammable releases). • Weather breaks such as compressor shelters and pump houses serve as confinement. Eliminate them where possible. If required, space them from the equipment to minimize confinement and permit some ventilation. Consider leaving the lower portion of the weather break open for heavier than air releases (e.g., LFG), and the upper portion for lighter than air releases (e.g., hydrogen). • Air-cooled heat exchangers are a source of both confinement and turbulence. Elevate them as much as possible with significant venting around all sides. If possible, elevate the air-cooled heat exchangers to above 3 times the height of a potential vapor cloud.

6.6. Relative Location of Equipment Another item to keep in mind when laying out the unit is the relative location of one piece of equipment with respect to another. Separate equipment with a high skin temperature that may be a potential ignition source from potential sources of flammable releases. This equipment includes internal combustion engines, combustion gas turbines, high temperature piping, chemical dryers, and others. Certain chemicals warrant special attention during layout such as those that autoignite, self-ignite, or are static accumulators. Locate these chemicals based on their chemical properties and separate them from the main portion of the process area or other areas containing flammable materials.

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The equipment distances provided in the Tables in Appendix A and those depicted on plot plans typically show the distance from equipment edge to equipment edge. It must be recognized that piping, valving, and controls will be located within this separation distance; thus, the net space available for access will be reduced.

Example A refinery was built in 1960 based on an innovative design approach. This approach was to build a totally integrated refinery, which would minimize pipe lengths and plot space. This approach was taken due to very limited plot space available and the desire to minimize capital investment. Ten years into operation, there was a pump fire. Due to the tight design, the pumps and equipment were located directly under the air-cooled heat exchangers. Firefighting was difficult due to limited access and the fire quickly escalated beyond the firefighter’s capability to control the fire. The entire process area was a loss. The refinery was never rebuilt.

Lesson

Capital costs and fire, explosion, and toxic risks must be balanced. The inability to combat an emergency, either through automatic fire protection systems or manual firefighting efforts, can lead to loss of the entire project and potential high risk to the surrounding area.

6.7. Equipment with Air Intakes When locating air intakes for the equipment listed below in relation to adjacent equipment, consider wind directions, a clean air source, and the consequences of toxic or flammable gas flowing into the air intake. Consider a shutdown system triggered by gas detection for the equipment listed below. Equipment of concern includes the following: • Internal combustion engines and turbines • Air compressors and blowers • Inert gas generators • Furnaces and boilers • Buildings using a pressurization system for electrical area classification purposes

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• HVAC units for buildings • Air separation units

6.8. Equipment-to-Equipment Separation Distances This section addresses flammable materials. Materials that are toxic, reactive, or pose a dust explosion potential may require additional consideration in layout and additional layers of protection to provide control in the case of an incident. Locating equipment handling toxics inside of a ventilated enclosure may be considered as discussed in Section 6.4. Further information on handling of these materials may be found in the CCPS Guidelines for Safe Storage and Handling of Reactive Materials (CCPS, 1995, no. 19).

6.8.1. Process Unit Spacing Separate equipment in a process unit by at least 100 ft (30 m) from equipment handling flammable materials in adjacent units or offsite equipment. This spacing is required to minimize risks due to maintenance activities in one unit while the adjacent unit or offsite equipment remains in service. This spacing applies to situations where both or only one of the units contains flammable materials. In instances where neither unit contains flammables, this spacing may be reduced to that required for maintenance and emergency access. The typical distance separating a process-unit battery limit from an onsite roadway with unrestricted access is 50 ft (15 m). This spacing may be reduced with the implementation of access controls on the roadway. As stated in Section 6.2, provide emergency access to units from two directions in a path that does not require crossing an adjacent unit. Accessways should be provided at least every 200 ft (61 m). An accessway should be at least 20 ft (6 m) wide. These access ways will permit emergency egress, facilitate firefighting, serve as firebreaks, and serve as separations between equipment groups to minimize potential explosion overpressures.

6.8.2. Equipment Handling Inert Materials There are no separation distances stated in Table A for equipment handling inert materials (nonflammable, noncombustible, nonreactive, or nontoxic)

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such as nitrogen, steam, or water. When locating this type of equipment, consider: maintenance access, the equipment criticality (i.e., equipment necessary to safe shutdown or emergency response), replacement cost, and potential downtime.

6.8.3. Vessels Consider the potential effects of a spill fire from vessels with large liquid volumes when locating adjacent equipment. Large liquid volumes can be found in towers, pressure vessels, reactors, surge drums, accumulators, tanks, and desalters. Separate these types of vessels from fired heaters and reboilers that are not associated with that vessel. Separation from unit pipeways will provide portable firefighting access. Do not locate these vessels beneath pipeways or air cooled heat exchangers. The spacing distances between smaller diameter equipment handling material that does not present a hazard due to its chemical properties may be reduced from the 15 ft (4.5 m) provided in Appendix A to 5 ft (1.5 m). However, access for maintenance and firefighting must be provided.

6.8.4. Reactors Reactor spacing can be reduced from the values given in Appendix A when the reactor and the other piece of equipment both handle the same material, are of the same level of construction, and pose the same hazards. Maintenance access must be provided. Reactors in identical service may be located as close as maintenance access and firefighting needs permit. Locating a reactor close to associated equipment may be preferable in cases where highly hazardous materials (such as acetylene or hydrofluoric acid) are involved as this minimizes the piping lengths between equipment. Greater fire protection may be warranted where separation distances are reduced. No separation distance is provided here or in the tables for reactors containing toxic materials that are neither flammable nor explosive from other process equipment. Base distances to occupied areas on risk analysis. The spacing distances in Appendix A do not apply to reactors located inside of bays or containment walls. In this case, explosion analysis should be used to determine the location and dictate the design requirements.

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6.8.5. Scrubbers and Catch Tanks Scrubbers and catch tanks may contain volumes of flammable materials. Treat them as process vessels for spacing considerations.

6.8.6 Heat Exchangers When locating heat exchangers, provide sufficient access to permit safe blinding and tube bundle removal. Other than stacked exchangers, do not locate equipment above heat exchangers containing flammable liquids, or combustible liquids that are heated above their autoignition temperature.

6.8.7 Air Cooled Heat Exchangers Updraft air-cooled heat exchangers draw air through the cooler and may also draw the heat and fire in the same direction. The additional heat input to the cooler from the fire can cause high temperature and overpressure of other equipment. Additionally, the metallurgy that makes the fins appropriate for heat transfer also makes them highly susceptible to damage from heat. Do not locate vessels or pumps containing flammable or combustible liquids beneath air-cooled heat exchangers. , Do not locate heat exchangers containing flammables or combustibles that are heated above their autoignition temperature beneath air-cooled heat exchangers. Do not locate multiple flanges and valves, such as in control stations, under air-cooled heat exchangers. Separate air-cooled heat exchangers from ignition sources such as fired heaters.

6.8.8 Fired Heaters Fired heaters are a continuous ignition source. Locate them upwind of potential flammable vapor release sources to minimize the potential for fires and explosions. Locating fired heaters at the unit battery limits provides good access and maximizes separation. Separate fired heaters from equipment containing flammable liquids and vents that might release vapors. An exception to this distance is when heaters are feeding reactors and it is desirable to minimize the length of the large diameter transfer line.

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6.8.9 Unit Flares Unit flares may include thermal oxidizers, ground flares, and elevated flares. Locate unit flares upwind from process equipment to minimize the potential for ignition. Flare spacing depends on the flare height, load, and the radiant heat level permitted. Maximum permissible thermal radiation, luminosity, and noise levels are typically mandated. Distances to these levels can be based on consequence modeling or on calculation methods such as those provided in API RP 521. Consider the risk of windblown embers from an elevated flare tip. They may ignite materials below the flare. Locate the flare at a safe distance from equipment and storage tanks containing flammable or combustible materials to avoid this concern.

6.8.10. Gas Compressors and Expanders Treat steam- or motor-driven gas compressors the same as pumps in regard to spacing. Locate all flammable gas compressors downwind and separated from fired heaters. Do not locate equipment above gas compressors. Separate suction knockout drums, intercoolers and intercooler accumulators from the compressor to provide firefighting and maintenance access.

Example An engine driven compressor with a large flywheel was located near a tank containing a highly toxic chemical. The attachment of the flywheel to the shaft failed and the flywheel came loose and rolled toward the tank. The flywheel was stopped by a steel post designed to restrict vehicle traffic near the tank.

Lesson Consider the orientation of rotating equipment to reduce the possibility of mechanical failures impacting adjacent equipment.

6.8.11. Pumps Pumps pose a fire potential due to the leaks from the seals, temperatures of pumped fluids, and the discharge pressures. Pump fire likelihood may be reduced through the use of higher integrity seals (e.g., double seals) and reg-

112

Guidelines for Facility Siting and Layout

ular monitoring programs. Although a pump fire may be detected early and controlled quickly with effective fire protection and firefighting, significant damage to adjacent equipment and the pump may occur depending on the pump location. Locating pumps under pipeways carrying flammable materials, controls cabling, and air-cooled heat exchangers can lead to significant damage and downtime from a relatively small pump fire. When a pump and its spare are exposed to a common fire hazard, additional separation between them may be justified especially if there is a significant business interruption concern. NFPA classifies a material as flammable or combustible based on its flash point. The operating temperature of the pumped fluid should also be used in this classification. Any combustible fluid heated above its flash point will have the characteristics of a flammable liquid and should be considered a flammable liquid in spacing and laying out equipment. Group pumps handling flammables above their autoignition temperature and self-igniting materials together and separate from other flammable pumps. This serves to group similar hazards and separate hazard levels to minimize damage due to spill fires.

TABLE 6.3 Pump Separation Distances Liquid Temperature

Pump location

Below flashpoint

Adjacent to but not under fireproofed pipeways and air cooled heat exchangers 15 ft (4.6 m) from nonfireproofed pipeways

At or above flashpoint

10 ft (3 m) from fireproofed pipeways where the pump is protected by a firewater spray system 15 ft (4.6 m) from non-fireproofed pipeways and air-coolers where pump is protected by a firewater spray system 15 ft (4.6 m) from fireproofed pipeways where the pump is not protected by a firewater spray system For nonfireproofed pipeways and air-coolers where pump is not protected by a firewater spray system, use consequence analysis to determine spacing

Note: Where the pump is handling materials that are self-igniting or above their autoignition temperature, conduct a hazard analysis to determine if greater spacing or additional layers of protection are required. Note: Where the pump is handling materials that are close to their flashpoint, good practice dictates that they be considered to be above their flash point or additional calculations are performed since there is significant variability in referenced flashpoint values.

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Separation distances between pumps and pipeways based on pump parameters and fire protection are described in Table 6.3. Locate transfer pumps outside of tank dikes. Treat transfer pumps as process equipment and separate from unit substations by at least 50 ft (15 m), and from main substations by at least 200 ft (61 m).

Example A typical 1950s or 1960s refinery unit layout located the charge pump at the beginning of a pump row. The pump row would be located in the center of the unit with the unit pipeway located above. The pipeway was also a convenient avenue to run the power and instrument control lines. In many cases, the charge pump was located near the control room or instrument house. The main power and instrument runs for the entire unit were in a single run back to the control house and were located in the pipeway directly above the charge pump. Many otherwise non-significant pump fires have resulted in significant downtime because of the damage to the power and instrument lines. In many units, these power and instrument cables are fireproofed. Typically instrument fireproofing is designed to ensure safe shutdown of the unit, which is estimated at 10 to 30 minutes whereas the pump fire might burn for an hour or more.

Lesson

The fireproofing served its design to allow for a safe unit shutdown. However, because the power and instrument cables ran directly above the pump, a small fire led to a long downtime. Locating critical facilities away from likely fire sources can minimize potential for extended downtime caused by small fires.

6.8.12. Cogeneration Facilities Cogeneration facilities include gas turbine-driven generators with waste heat steam boilers and alternative fuel fired boilers such as those burning petroleum coke. Treat cogeneration facilities as utility units for separation distance considerations.

6.8.13. Unit Isolation Valves Install unit isolation valves or battery limit valves in a safe, well-lit, accessible location near the process-unit battery limits. Locate the valves or the remote actuation point outside of the fire risk area.

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Guidelines for Facility Siting and Layout

6.8.14. Water Spray Actuation Valves Locate manual actuation valves for water spray outside of the fire areas of the hazards they are protecting. Locate manual water-spray actuation valves near the battery limits in a well-lighted and easily accessible area. Also, manual or automatic water-spray deluge valves should be located near the battery limits in a location convenient to the operators or emergency responders and in the expected path of travel. This location should be protected from fire and explosions.

6.8.15. Emergency Shutdown Valves Locate a manually operated emergency shutdown valve in an accessible location at least 50 ft (15 m) from the outer edge of a potential pool fire that might be associated with the equipment the valve is isolating. Locate remotely operated valve actuation stations at least 50 ft (15 m) from potential fire sources. Automatic valves may be located anywhere as long as they are fire protected so that they operate when needed.

6.8.16. Vents and Relief Vents to Atmosphere Vents, pressure relief, and rupture disk discharge points should be located to vent to a safe location. Locate these discharge points such that they do not create a hazard for operators or maintenance personnel on walkways or platforms. Location of these vents should be a safe distance from building HVAC intakes. Consequence modeling may be utilized to determine the distance from the vent that a hazardous concentration may exist.

6.8.17. Fire Pumps Fire pumps are required to be fully functional in emergencies. Consequently, locate them, and their source of motive power, away from potential fire or explosion impact areas and areas prone to flooding.

6.8.18. Fire Hydrants and Monitors Space fire hydrants protecting process units no greater than 200 ft (61 m) apart around the process unit perimeter. Locate hydrants at the unit accessways to facilitate manual firefighting in the unit with hoses. In tank farms, space fire hydrants no greater than 200 ft (61 m) apart with at least

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115

one on each quadrant. It is a good practice to locate a fire hydrant next to each foam fire truck connection point on storage tanks to provide a minimal distance between the foam fire truck and the hydrant. Place monitors as fire protection assessments dictate. Typically they are located 50 ft (15 m) from the fire risk area they are protecting. Additional firewater monitors may be necessary if large equipment obstructs their range of projecting firewater.

6.8.19. Pipeways Pipeways are structures that support pipes, power leads, and instrument cable trays. They are referred to as pipeways, piperacks, or pipebands. The piping they support may contain process fluids or utilities. Main pipeways transfer material from the unit pipeway to storage or utility areas. Unit pipeways are located within the battery limits and transfer material between the unit process equipment. Pipeways may be elevated or at grade. Main pipeways should be located outside of process unit battery limits. Separation distances from main pipeways are based on substantially all welded pipe in the pipeway. Treat sections of the pipeway containing numerous flanges, process control valve stations, vents, drains, or other release sources as process area pipeways in regard to spacing. Evaluate pipeways handling high hazard chemicals (such as MIC, chlorine, or acetylene) to consider their safe layout. Pipes handling highly corrosive materials such as aqueous HCl should be located on the bottom piperack tier to prevent damage to other pipes and cables if there is a loss of containment. Do not locate pipeways where they might put emergency response equipment (including fire pumps) at risk. Route to avoid damage from cranes. Consider routing incompatible materials in separate pipeways.

6.8.20. Tanks Inside Battery Limits This section applies to in-process tanks and storage tanks containing flammable or combustible liquids within battery limits. Limit storage tanks within battery limits in number and size. Separate storage tanks from process equipment. Treat smaller storage tanks (less than 10,000 gallons (38,000 l) as process vessels (such as towers, drums, and KO pots) for spacing concerns.

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For tanks larger than 10,000 gallons (38,000 l), the values provided in Appendix A may be used as a starting point with further definition provided through a hazard analysis.

6.8.21. Unit Substations and Electrical Switch Racks For fire considerations, separate unit substations from process equipment handling flammables. Do not locate the switchgear room either above or below the control room. Do not locate HVAC on the roof of a control building unless it is provided with independent support. All switch racks should meet electrical classification requirements. Separate electrical switch racks supporting shutdown or emergency functions from equipment handling flammables by at least 20 ft (6 m) and from fired heaters or gas compressors by at least 50 ft (15 m).

6.9. Multi-Chapter Example Continuing with the example presented in Chapters 4 and 5, the topic of laying out equipment within a process unit is the next step.

Example Although all the process details are not yet defined, the Process Engineer has a good understanding of the pieces of equipment and their sizes. Based on this information the first pass at laying out the unit within the plants can begin. Locate the pieces of equipment the appropriate distances from each other as noted in the tables in Appendix A. The ethylene plant is divided into separate units: the cryogenic unit, the furnace cracking unit, and the product unit. The ethylene plant layout is presented in Figure 6-1. For the purposes of illustration, we will develop the layout for only one of the processes within the ethylene plant, the furnace cracking unit. Hydrocarbon feedstock streams supplying the ethylene process can include: ethane, propane, or butane. The feedstock streams are sent to the tubes of a cracking furnace that is heated by burning fuel gas. Steam injection is utilized in the tubes to control yields and prevent coke formation.

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Figure 6-1. The Ethylene Plant Layout

Subjecting the feedstock to high temperatures results in a partial conversion of the feedstock to ethylene and hydrogen. After the cracking furnace, the process stream is compressed to a higher pressure using “cracked gas compressors” and is then sent to a cryogenic plant for separation and purification. The predominant products of this process are ethylene and propylene. The major pieces of equipment in the cracking furnace unit are listed below: • The superheater and five ethylene cracking furnaces are located together on the upwind side of the process and are separated from the pipeway. • The process includes two cracked gas compressors. As these are a potential release point, they are located on the opposite side of the unit from the furnaces. This maximizes separation and puts them downwind of the potential ignition sources

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• As in most processes, there are a large number of pumps. These are grouped according to their risk level. For instance, the pumps handling hydrocarbons at high temperatures and pressures comprise one group. The boiler feedwater pumps comprise another group. These pumps are located in a row along an accessway to permit lift equipment to access the pumps for maintenance purposes. • The quench process equipment, comprised of various vessels, is grouped together and located downwind of the furnaces. The heat exchangers are laid out providing access for pulling tube bundles during maintenance operations. • The pump row is located adjacent to the unit pipeway. The pipeway is fireproofed and the pumps are protected with a firewater spray system. This will minimize the probability of a small pump fire damaging the air-cooled heat exchangers or electrical cables within the pipeway and causing significant downtime. • A number of firewater spray systems are specified by the fire protection or safety engineer. The actuation station for these systems is located in a bank at the edge of the unit in the direction of the control room. This places the actuation points outside of the fire hazard areas, makes them easily accessible, and places them on a likely path of travel in case of an emergency. • All equipment is separated from adjacent equipment based on the typical spacing tables provided in Appendix A. The fire protection or safety engineer is consulted when it is a challenge to meet the tables and additional fire protection and loss prevention measures are identified. Typical spacing distances between the equipment listed above is obtained by utilizing Table A in Appendix A. The cracking furnace unit layout is developed based on this information and is presented in Figure 6-2.

Lesson Laying out the individual pieces of equipment within a unit may be accomplished by utilizing the typical spacing tables provided in Appendix A. The process parameters including the materials being handled and their temperature and pressure will impact the spacing distances and should be understood before the layout is begun. The concept of grouping like risks together (pumps, furnaces) will facilitate the layout and optimize real estate. Prevailing wind direction must be considered when locating poten-

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tial ignition sources and equipment with the potential to release flammable materials.

Figure 6-2. The Furnace Cracking Unit (1 ft equals 0.304 m). NM: no minimum; NA: not applicable

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Optimize the Layout

7.1. Layout Method Review Laying out a complex, site, plant, or unit can be a challenging exercise. There are safety, environmental, financial, and public concern risks to balance with project cost and schedule goals. Layout development involves many different areas of expertise. The layout development process is an iterative one that develops as various needs are recognized and changes suggested. It will help to involve as many experts as early as possible in project development so that they can work together as information becomes available to optimize the layout. Making changes on paper during project design is much easier and more cost-effective than changing steel in the field. This multi-discipline early involvement will lead to a site that poses fewer risks, fewer changes in project development, and a more cost-effective project life cycle. This need for early involvement is heightened in fast-track projects, where a normal project timeline is compressed. In these projects there is even less time to involve specialists, complete studies, and make changes. The earlier specialist input is sought, the easier it will be to incorporate change in the project design. Safety and environmental engineering should be involved throughout the development process to ensure that hazards and risks are managed to corporate and or regulatory expectations. Often there are decisions to be made on how best to balance the various types of risk and costs. Many companies have corporate guidelines available to assist in this effort. Also, there are CCPS Guideline books listed in the reference section of this book that can assist with risk management efforts. In general, risks can be more costeffectively managed when they are addressed early in project development. This is because early in the project there are more prevention and mitigation options available to the project team.

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There is a large amount of both site and process data to be gathered and considered in the layout and spacing process. This data may be used to group plants, units, and equipment items with similar risks and segregate these risk groups from one another. This is a cost effective way to manage risk. This minimizes the probability of an incident occurring or escalating because higher risk equipment is located away from lower risk equipment. It also allows risk minimization measures (e.g., fixed protection systems, containment systems, detection systems) to be installed efficiently around the higher risk equipment rather than across the entire site. Once these blocks are laid out, the separation distances between the blocks and between the individual pieces of equipment may be determined through either of two methods or a combination of the two. The two methods are: • Utilizing spacing tables • Utilizing fire, explosion, and toxic release consequence modeling. Although spacing tables may not provide an exact, analytical answer, they are a means to quickly, and thus cost-effectively, lay out a site while taking advantage of significant experience contained in the spacing table. When spacing tables are used, exercise care to ensure that the spacing table is applicable for the subject process and hazard. If the spacing table is not applicable to the process being built, or if the concern is an explosion or a toxic release, then use the second method as described in the following paragraph. The second method is to develop spacing distances for the site’s specific layout and process parameters through fire, toxic, and explosion consequence modeling. This can be a time consuming endeavor given the large numbers of equipment items involved in a site layout. The basic steps when taking this approach are described in Chapter 5. The best solution is likely a combination of the two approaches and is depicted in Figure 7-1, which is a repeat of Figure 5-2. Use the spacing tables for the first layout. This will suffice for most equipment spacing. Follow with a more detailed layout for those distances of concern (i.e., because the real estate is not available or there is a specific high-risk operation). Toxic concerns and explosion concerns related to buildings will require consequence modeling to develop a site-specific spacing distance as described in API RP 752 or the CCPS Guidelines for Evaluating Process Plant Buildings for External Explosions and Fires.

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Figure 7-1. Site Layout Flowchart

7.2. Layout Issues Resolution Frequently, even with a long project schedule and appropriate specialist involvement, there are equally appropriate site layouts. There may also be challenges in finding an acceptable layout design because plot area is not adequate for the spacing desired. At this point, additional consequence modeling and risk assessment can be utilized to assist in quantifying the concerns, balancing the risks, and identifying potential prevention and mitigation measures. Some examples are provided below. • Fire consequence analysis can be used to estimate the extent of the potential fire area given the specific equipment parameters (e.g., area drainage to minimize liquid pool accumulation or the type of release fire that is likely). This may allow a reduction in spacing between equipment.

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• Toxic consequence analysis can be used to estimate the downwind concentration of a material, which could be helpful in locating a “vent to safe location”. • Explosion and toxic consequence analysis can be used to estimate the extent of potential hazard areas, which could assist in determining the distance from the process unit to the property line. • Risk analysis can be used to estimate the financial impact of reducing spacing and potentially increasing the extent of a loss from a fire. • Layer of protection analysis can be used to consider all types of protection (such as spacing, instrumented systems, and fire protection) to assist in providing appropriate levels of protection where spacing may not be adequate and additional protection is prudent.

Example A refinery decided to install additional LPG processing facilities and pressurized LPG storage. An analysis was conducted to determine if the proposed location for the new equipment presented a risk to off-site or in-plant personnel. The consequence analysis included process unit vapor cloud explosions, flash fires, jet fires, pool fire, catastrophic sphere failure and vessel BLEVEs (boiling liquid expanding vapor explosions). This data was used to qualitatively determine the magnitude of the increased risk associated with the project. The following is a description of a few of the scenarios evaluated and the results. Propylene Unit Piping Failure—This scenario assumes a 4-inch (10 cm) hole resulting in the release of propylene and a subsequent vapor cloud explosion. The blast impact at the nearest building is determined to be of negligible concern. If the release resulted in a jet fire, the jet could impact the nearest building. For this reason, a recommendation was made to relocate the building. BLEVE—This scenario assumes that a fire impinges on a propylene sphere and the sphere undergoes a BLEVE. The calculated thermal radiation levels at the property line indicate that there would be minimal off-site impact. It was qualitatively considered that the off-site impact from shrapnel from a BLEVE posed a low risk based on the distance of the sphere to the community.

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Catastrophic Sphere Failure—This scenario evaluated a catastrophic failure of one of the propylene spheres and the resulting vapor cloud consequences. Although a very large flammable cloud would form in this scenario, there would be no expected off-site impact since the hazard zone was well within the 1 mile (1.6 km) distance to the property line. If the resulting cloud travels toward the process area, an explosion or fire could result. The distance from the sphere storage to the closest process is approximately 200 m (660 ft). The probability of this scenario is determined to be very low and the distance is judged to be appropriate. Based on this analysis, the proposed locations of the propylene unit and the propylene spheres were determined to not significantly increase the existing in-plant and off-site risks and the proposed siting was endorsed with the provision of relocating the one building of concern in a jet fire scenario.

Lesson Use risk analysis to assist in quantifying the concerns, balancing the risks, and identifying potential prevention and mitigation measures. The jet fire consequence prompted the relocation of a building. The sphere failure, with a low probability and thus low risk, did not warrant a change in layout.

7.3. The Right Answer Laying out a complex, site, plant, or unit is a challenging exercise. One must also be aware that what may be acceptable today may be unacceptable tomorrow. Societies increasingly demand higher standards for processing sites. Periodic review of risk is necessary as the facility technology changes, the process changes, the site expands, the regulations change, and the surroundings outside the fence change. Increased spacing provides better flexibility as future demands evolve. What is the right answer in siting and laying out a complex, site, plant, or unit? There isn’t just one answer that fits every site. The site selection and layout must facilitate maintenance, operations, emergency response, corporate goals, and the needs of the community. The answer that is appropriate for your project is one that balances the risks and costs of today. It must also anticipate the needs of tomorrow.

8

Case Histories

This chapter provides a selection of case histories to illustrate both the appropriate manner in which to address facility siting and layout as well as the consequences when the effort is not done well. These case histories include both actual events and illustrative scenarios.

Case History 1: Consider BLEVE potential in siting of LPG storage At approximately 05:35 hours on 19 November 1984 a major fire and a series of catastrophic explosions occurred at the government owned and operated PEMEX LPG Terminal at San Juan Ixhuatepec, Mexico City. Three refineries supplied the facility with LPG on a daily basis. The plant was being filled from a refinery 248 miles (400 km) away. Two large spheres and 48 cylindrical vessels were filled to 90% and 4 smaller spheres to 50% full. A drop in pressure was noticed in the control room and also at a pipeline pumping station. An 8 inch (20 cm) pipe between a sphere and a series of cylinders had ruptured. Unfortunately the operators could not identify the cause of the pressure drop. The release of LPG continued for about 5–10 minutes when the gas cloud, estimated at 660 ft×490 ft × 6.6 ft (200 m × 150 m × 2 m) high, drifted to a flare stack. It ignited, causing violent ground shock. A number of ground fires occurred. Workers on the plant tried to deal with the escaping LPG and the emergency response, taking various actions. At a late stage, an emergency shut[down] was initiated. About fifteen minutes after the initial release, the first BLEVE occurred. For the next hour and a half there followed a series of BLEVEs as the LPG vessels violently exploded. LPG was said to rain down and surfaces covered in the liquid were set alight. The explosions were recorded on a seismograph at the University of Mexico (HSE, 2002, Skandia, 1985). [From Loss Prevention in the Process Industries 2nd ed. by F. P. Lees. Reprinted by permission of Elsevier Science Ltd., Lees 1996.]

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This incident resulted in 650 fatalities, more than 6400 injuries, and destruction of the terminal and many of the homes in the neighborhood located adjacent to the terminal.

Lesson

LPG vessels have the potential to BLEVE, which can have consequences at great distances. • Consider the surrounding areas and future development when siting LPG vessels. The population was likely not near the site when it was constructed which is often the case. However, acquiring additional land beyond that needed for the plant facilities at the time of siting the plant would have provided a buffer area between the LPG Vessels and future surrounding community. • Consider all potential credible incident scenarios when laying out the equipment on the site. The many LPG vessels at the PEMEX site were closely spaced. Providing more land area to better space vessels and permit good drainage and LPG spill containment could have reduced the consequences of the failure (e.g., less chance of BLEVE and reduced amount of LPG released). Better access could have permitted a better chance of controlling the fire and containing the release. This equates to more land area or reduced numbers of vessels on the land available. Manage the total number of LPG storage vessels located in an area by addressing the potential magnitude of the consequences. • Consider the orientation of LPG cylindrical vessels as they may launch in the direction of their axis during a BLEVE and escalate the incident. The cause of some of the damage to the spheres may have been due to shrapnel from exploding horizontal vessels. Note in Figure 8-1, some of the horizontal storage tank ends were pointed toward the spheres. • Consider the hazard of the facility and assure that adequate fire protection is provided.

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Figure 8-1. LPG Terminal at San Juan Ixhuatepec before and after (Skandia, 1985)

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Case History 2: Separate occupied buildings from equipment with runaway reaction potential Unit 1, a relatively small process unit was located near one end of a chemical complex. The feedstock for Unit 1 came from the large process units located in the center of the complex. All of the process units were well spaced for fire hazards. The majority of the occupied buildings including administration, engineering, shipping/receiving, and warehousing were generally arranged along the plant main entrance at the opposite end of complex from Unit 1. These buildings had good separation from the process units. However, the Maintenance Shop and the Contractor Building (a small building that contractors used for a workshop) were situated approximately 250 ft (75 m) from Unit 1. The tank farm was located beyond the Maintenance Shop from Unit 1, with the closest tank being about 410 ft (125 m) from Unit 1. The closest tanks contained toxic, non-flammable materials in an assortment of atmospheric and pressurized storage tanks. Unit 1 suffered a runaway reaction resulting in catastrophic failure of a reactor. Fragments from the reactor were thrown over 3300 ft (1000 m). Large pieces of structural steel, piping and neighboring vessels were thrown up to 980 ft (300 m). The blast collapsed the Maintenance Building, resulting in several fatalities. Metal panel siding was torn from the Contractor Building, but the structure remained standing. The Maintenance Building and Contractor Building were both enveloped in the plume. Damage to buildings at the main entrance included cracked walls, buckled metal panels, broken windows, bent doors, and dislodged false ceilings. However, none of the buildings collapsed and all but one were put back into immediate use during emergency response. The complex was situated in a rural area with only two nearby structures, both more than 980 ft (300 m) from the nearest plant fence.

Lesson Although the site was well spaced for fire considerations, the runaway reaction potential and resulting overpressure was not adequately addressed in the siting. The siting and layout minimized the impact on most buildings and permitted emergency response activities, but the maintenance and contractor buildings were damaged resulting in injuries and fatalities. A preliminary hazard analysis may have identified the possibility for runaway reaction and its potential consequences. Consideration could then have been given to the location of the reactor with respect to the toxic mate-

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rial storage area and the location of the buildings with respect to the reactor. A different site arrangement may have reduced the risk of fatalities and injuries resulting from the reactor failure. It is important to consider all potential consequences in site layout including fires, explosions, and toxic releases.

Case History 3: Consider siting of high volumes of reactive chemicals In 1987 the PEPCON Ammonium Perchlorate plant in Henderson, NV experienced a fire and one of the largest industrial explosions in history. Ammonium perchlorate is the oxidizer used in solid rocket motors. The PEPCON explosion occurred about 1 year after the Challenger space shuttle accident. PEPCON had a very large inventory of ammonium perchlorate due to a halt in production of shuttle motors by NASA. However, Morton Thiokol had PEPCON continue ammonium perchlorate production knowing that NASA would resume production. They had in excess of 10 million pounds (4.5 million kilograms) of ammonium perchlorate in storage. Ammonium perchlorate was classified as an oxidizer prior to the PEPCON accident. All of the transportation and safety tests for classification of hazardous materials had been performed, primarily by the military. Thus, no precautions were being taken for a detonable material. The PEPCON plant was located in the desert outside of Las Vegas, with good separation from neighbors except one food processing plant, a marshmallow plant that immediately adjoined PEPCON’s property. Although the large separation was not the result of planning for off-site consequences, it proved critical in minimizing off-site damage and injuries. The PEPCON site had experienced neighborhood encroachment. A new residential area was being developed a few miles from PEPCON. An entire subdivision was built, and the opening weekend at which the houses would be sold was planned for just one or two weeks after the time of the explosion. All of the brand new houses were vacant. There is a debate about the cause of this accident and why the ammonium perchlorate fire was difficult to extinguish. Ammonium perchlorate by itself burns poorly and is easily extinguished with water. The PEPCON plant was built over a 16-inch (41-cm) natural gas main. This pipe was found to have a flaw in a weld. Ammonium perchlorate in the presence of any fuel causes a very aggressive fire. PEPCON personnel could not stop the initial fire with water, which was very unusual. One theory was that a natural gas

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leak provided fuel. From a siting standpoint, putting an oxidizer plant over a natural gas main may not have been the best decision. The final explosion had a TNT equivalent on the order of 2 million pounds (0.9 million kilograms). The nearby homes suffered damage ranging from extensive window breakage to broken roof joists. Minor injuries would have resulted had the area been populated. The PEPCON plant was essentially leveled. The marshmallow plant was still standing, but had severe damage. There were only two fatalities one of which was the PEPCON plant manager who gave the evacuation order early after fires started, and who remained in the Administration Building calling emergency responders. A critical decision the plant manager made was for staff not to use cars; he instructed them to evacuate on foot into the desert which proved to be much quicker. The ability to evacuate quickly saved many lives.

Lesson It is important to know the site characteristics as well as the characteristics of the materials being handled. Materials that react with one another should be separated from each other on the site, such as the ammonium perchlorate and the natural gas main. Recognizing the potential for offsite damage and siting a facility in a remote location is only the beginning. Ensuring that the public cannot encroach on the facility boundaries will ensure that the risk of offsite impact is managed.

Case History 4: Understand and consider the potential of highly reactive chemicals in facility siting At 8:14 pm on February 19, 1999, a process vessel containing several hundred pounds (over one hundred kilograms) of hydroxylamine (HA) exploded at the Concept Sciences, Inc. (CSI), production facility near Allentown, Pennsylvania. Employees were distilling an aqueous solution of HA and potassium sulfate, the first commercial batch to be processed at the new CSI facility. After the distillation process was shut down, the HA in the process tank and associated piping explosively decomposed, most likely due to high concentration and temperature. Four CSI employees and a manager of an adjacent business were killed. Those injured included CSI employees, people in nearby buildings, firefighters, and security guards. The production facility was extensively damaged. The explosion also caused significant damage to other buildings

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in the Lehigh Valley Industrial Park and shattered windows in several nearby homes. Estimated property damage in February 1999 was $3.5 to $4 million (see Figure 8-2). CSI’s design and safety review was inadequate given the hazards of highly concentrated HA. A critical evaluation of process materials, conditions, equipment, and development experience would have indicated that credible scenarios presented the potential of a catastrophic HA explosion. Facility siting evaluations typically include process safety analyses and reviews of government regulations, industry guidelines, and local emergency planning requirements. CSI was located in a multiple-tenant building within a suburban industrial park. Fortunately, the timing of the explosion—8:14 pm on a Friday—limited the number of fatalities and injuries. [Reproduced with the permission of the United States Chemical Safety and Hazard Investigation Board, US CSB, 2002.]

Lessons

Facility siting should consider all potential hazards (e.g., fire, explosion, toxic material release) to people, property, and the environment. Siting evaluations should be an integral part of process design. If CSI had performed an adequate Process Hazards Analysis for the planned HA manufacturing operation, it would have recognized the danger to the public. Management could have selected an alternate site where no one at neighboring facilities would be exposed to such a substantial risk.

Figure 8-2. Concept Sciences, Inc. Site

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Case History 5: Understand and consider expansion issues and design options A plastics company decided to increase resin manufacturing capacity at the plant in Figure 8-3. The expansion included two new reactors, new cooling towers, a new peroxide storage building and expansion of the catalyst preparation building. Design reviews and the preliminary hazard analysis identified the following issues: • Expansion of the reactor building to the east would impair plant maintenance access. Expansion to the south is preferred but radiant heat from the flare in an emergency situation was a concern. • Existing pipeways were at capacity. The cooling tower and the associated distribution piping needed to be located to not interfere with plant access. • The new peroxide storage building needed significant separation distance due to the potential for decomposition of stored catalyst. NFPA 432 ”Storage of Organic Peroxide Formulations” was consulted for safe separation distances. • The catalyst preparation process included the opening and closing of vessels that contained flammable liquids which resulted in a Class I, Division 1 electrical area classification. Expansion of the catalyst

Figure 8-3. Original Layout

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preparation building would have resulted in expanding the classified area surrounding the catalyst preparation building. The control building needed to remain in an unclassified area. The following analysis and changes were made to accommodate the layout shown in Figure 8-4. A flare loading and radiant heat study was completed. The radiant heat in an emergency was judged to be moderate so the reactor building was expanded to the south. The roofing materials on the reactor building were changed to aluminum to assure that extended exposure to radiant heat from the flare would not damage the roof. The cooling towers were located to the south so that a new pipeway would not impair plant access. Excess capacity was designed into the pipeway support structure to allow for future expansion. An inherently safer design approach was taken to analyze the peroxide decomposition hazard. A change in catalyst formulation allowed a less reactive peroxide to be used in the process. A reduction in peroxide hazard classification reduced the safe separation distances. Increased automation of the catalyst solution preparation process reduced the electrical classification to Class I, Division II and allowed the catalyst preparation building to be expanded without encroaching on the nonclassified control building.

Figure 8.4. Layout after Expansion Project

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Lesson

Design reviews and preliminary hazard analysis can identify areas for consideration both in terms of the site constraints and the material properties and handling needs. Inherently safer design concepts and these analyses can aid in identifying other potential layers of protection in addition to spacing and separation.

Case History 6: Consider jet fire consequences on adjacent buildings A clean out operation of a batch still, known as “60 still base,” was organized in order to remove residues. This vessel had not been cleaned since it was installed in the nitrotoluenes area in 1961. An operator dipped the sludge to examine it and reported the sludge as gritty with the consistency of soft butter to management. No sample was sent for analysis nor was the atmosphere inside the vessel checked for a flammable vapor. It was mistakenly thought that the material was a thermally stable tar. In order to soften the sludge, which was estimated to have a depth of 14 in. (34 cm), steam was applied to the bottom heating element. Advice was given not to exceed 194°F (90°C). Employees started the clean out operation using a metal rake. The material was tar-like and had liquid entrained in it. Approximately one hour into the cleaning process a longer rake was used to reach further into the still. The vessel’s temperature gauge in the control room was reported to be reading 118°F (48°C). Instructions were given to isolate the steam. A number of employees involved in the raking left the still base to get on with other tasks. One person left on the scaffold had stopped raking and noticed a blue light, which turned instantly to an orange flame. As he leapt from the scaffold an incandescent conical jet erupted from the manhole. This projected horizontally toward the control building. A vertical jet of burning vapor shot out of the top rear vent to the height of the distillation column nearby. The jet fire lasted for approximately one minute before subsiding to localized fires around the man-lid and buildings nearby. The force of the jet destroyed the scaffold, propelling the manhole cover into the center of the Meissner control building. The jet severely damaged this building and then impacted on the north face of the main office block causing a number of fires to start inside the building. Crown copyright material is reproduced with the permission of the Controller of HMSO and the Queen’s Printer for Scotland. HSE, 2002.

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Lesson Knowing the identity of the chemicals being handled and understanding their properties is imperative in the safe handling and siting of materials. Without knowing what the chemical is, the risks of fire, explosion, and toxic impact cannot be considered. Different from pool fires, jet fires involve pressure and velocity thus causing them to extend great distances, though frequently for a limited time. These potential distances for significant damage must be considered in siting especially relative to occupied structures.

Case History 7: Consider siting and layout in management of change A plastic company that manufactures resins was considering adding a process that includes hydrofluoric acid (HF) as a raw material. The HF would enter the plant by rail car and the cars would need to be unloaded and cleaned. The initial hazards review identified releases of HF during unloading or rail car cleaning as potential concerns. The company undertook consequence analysis to better define the hazards. The dispersion analysis identified that a moderate size release at the unloading pressure and temperature could impact onsite and offsite locations. Cleaning the rail cars was expected to be less of a concern due to lower pressures and much smaller quantities available for release. Several engineering solutions were considered including not adding the HF process. A cost benefit analysis was performed and the decision was made to unload and clean the railcars within a large enclosure constructed for the purpose. The unloading enclosure was temperature and ventilation controlled, included HF detection, and fitted with vent scrubbers and water deluge.

Lesson Changes such as process modifications including changing the materials being handled, their temperature, pressure, or volumes can have a major impact on the risks associated with the existing site. The existing site may have been laid out based on less severe hazards and risks. Thus, the distances to populations, structures, and equipment may not be adequate for the new hazards and risks being introduced. In this case, the hazards and risks associated with the process modifications were assessed. Additional spacing was considered but found to be either cost prohibitive or not feasible. Therefore additional layers of protection were incorporated into the design of the new process to compensate for the increased risk.

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Case History 8: Use similar measurement unit systems on projects sited together Here is a historical example of what can go wrong when plants use several different measurement units. A Far East refinery was built in the late 1960s by a US engineering design and construction company. All design information on drawings and in project documentation as well as specifications for instrumentation and process equipment was documented in English units. About 10 years later, an expansion project using a Far East engineering design and construction company built new process units on the same site. The new units were integrated into the original process operation requiring some changes and additions to the older units. The contractor used the CGS metric system for design and equipment specification as per the current company standard for all overseas operations. The new unit control console was located in the same control room as the original refinery console with the new instruments measured in CGS metric units located alongside older instruments measured in English units for these integrated units. Another 5 years passed, and the refinery was expanded a second time. This new expansion was designed to SI metric system, as was the practice in industry at the time. Again, the control equipment was located in the same control room building. Due to the integration of the processes, SI metric instruments were mounted alongside CGS metric and English instruments. As you can imagine, the control panels were very confusing to look at but the real problem was in training the operators and maintenance crews to understand and convert from one set of units to another. To simplify operations and data communication, the operators and maintenance staff put a mark on each instrument to indicate normal operation. They began to operate according to the marks on the gauges instead of the actual process information. During an upset, the various measurement systems made fast response questionable. The problem was finally resolved years later with the installation of a new DCS system for the refinery. However operation and maintenance struggled with this confusion for years.

Lesson

The benefits from using a central control room for site expansions needs to take into account human factors issues. Using different units of measure can cause human factors issues that can lead to errors and even incidents.

Appendix A. Typical Spacing Tables

The following comments should be applied to the Tables contained in Appendix A. NA = Not applicable. No measurable distance is appropriate. NM = No minimum spacing requirement has been established for reasons of fire protection. Use engineering judgment for spacing and provide access for fire fighting and maintenance. S = Spacing is based on security needs and not on fire, explosion, or toxic concerns.

CAUTION: 1. Tables A through E include typical spacing values. Explanatory text is included in Chapters 5 and 6. 2. The typical spacing distances cited in Tables A through E are based on potential fire consequences (explosions and toxic concerns may require greater spacing). Variations in spacing may be warranted based on site-specific hazards and risks. Distances may be reduced or increased based on risk analysis or when additional layers of protection are implemented (such as: fire protection or emergency shutdown systems). 3. These tables are not applicable to enclosed process units. Miscellaneous typical spacing values are included in Table E.

NOTES: 1. Distances are measured horizontally. 2. Typical horizontal distances between buildings, process equipment, and property lines are shown and apply to the closest edge to closest edge dimensions. 3. Where unusual conditions require closer spacing, appropriate risk reduction measures should be considered. 139

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ter

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. .

Appendix B. Site Selection Data Requirement List

TABLE OF CONTENTS INTRODUCTION 1. INFORMATION TO SELECT A SITE 1.1. Maps and Surveys 1.2. Topography, terrain and soil properties 1.3. Site Specific Meteorological and Geological Data 2. TRANSPORTATION ISSUES 2.1. Product and Material Handling 2.2. Trucks 2.3. Pipelines 2.4. Railroad 2.5. Marine Facilities 2.6. Special Transportation Requirements 3. UTILITIES 3.1. Water Supply 3.2. Steam Supply 3.3. Fuel 4. ELECTRICAL AND COMMUNICATION SYSTEMS 4.1. Electrical Systems 4.2. Communication Systems 5. ENVIRONMENTAL CONTROLS 5.1. Wastewater Quality Control 5.2. Air Quality Control 5.3. Sanitary Sewage Collection and Treatment 5.4. Noise and Luminosity Level Design Limitations 6. FIRE, SAFETY, AND SECURITY 6.1. Fire and Safety 151

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6.2. Security 7. SITE FEATURES 7.1. Personnel 7.2. Housing 7.3. Site Support Facilities 8. SYSTEMS OF MEASUREMENT 9. CODES, STANDARDS, DESIGN FACTORS, UNITS

INTRODUCTION This site survey guideline is designed to assist survey groups investigating locations for a new site in obtaining the data needed to select the new site. The subject information is intended to address all sites including a remote new site location, where the availability of materials may be questionable and engineering services limited. In locations where these services are easily available, the survey group may disregard certain questions that appear obvious.

1. INFORMATION TO SELECT A SITE 1.1. Maps and Surveys 1.1.1. To expedite the initial layout and design, certain information should be obtained with least delay. This includes property survey data obtained either from existing civil engineering drawings or from property deeds obtained from local registration authorities. 1.1.2.

Establish the following features regarding the location of the new site through a general inspection of the property. 1.1.2.1.

Nature of the terrain (hilly, wooded, marshy, rocky) including natural drainage conditions and slope in relation to adjoining property. If possible, obtain contours of surrounding areas to determine storm water contributed to the new site.

1.1.2.2.

Buildings or other structures on the new site, their condition, settlement.

Appendix B. Site Selection Data Requirement List

1.1.2.3.

1.1.3. 1.1.4.

1.1.5.

153

Highways, roads, railways, waterways, swamps, or lakes that may affect the site layout. 1.1.2.4. Industrial buildings, farms, reservoirs, sewers, water mains, electric cables, etc. adjacent to the site that may affect layout considerations. Determine the elevation above sea level at the site. Obtain a general map of the area showing boundaries of the new site, elevations, contours, location and elevation of benchmarks. Obtain a map of the area showing the following: 1.1.5.1. Highways 1.1.5.2. Railroads and sidings 1.1.5.3. Streams 1.1.5.4. Surrounding communities 1.1.5.5. Airports 1.1.5.6. Town centers, malls and shopping centers, housing areas 1.1.5.7. Sensitive population centers such as schools, hospitals, day care centers 1.1.5.8. Nearby industrial sites and transportation centers 1.1.5.9. Farms and agricultural centers 1.1.5.10. Sewers, water mains, and storm drainage 1.1.5.11. Dumping grounds or buried tanks or pipes on the site 1.1.5.12. Natural gas and other pipelines 1.1.5.13. Environmentally sensitive areas (e.g. wetlands) 1.1.5.14. Future facilities that are in the planning stage, particularly if they may present an external exposure to your site. 1.1.5.15. Future population encroachment 1.1.5.16. Location of services that may be subject to interference from a new site or may interfere with the communication or operation of your site (these may include radio, television, or microwave communication equipment) 1.1.5.17. Note any specific zoning restrictions that may affect the new site.

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Guidelines for Facility Siting and Layout

1.1.6.

1.1.7.

1.1.8. 1.1.9. 1.1.10. 1.1.11. 1.1.12.

1.1.13.

1.1.14.

Develop or obtain an enlarged section of the site showing contours, if possible, to 1 to 2 ft (25 to 50 cm) and defining area and boundaries in relation to the true north and magnetic north. Obtain an aerial topographical map of the area with adjacent surroundings. Show what areas are available for future expansion. Determine the cost for land required for the site and right-ofways. Describe right-of-ways that are required. Determine the type of vegetation and precautions necessary to prevent soil erosion. Determine if there is a suitable area where soil can be discarded. Determine if dredging or fill will be required. Determine if bulkheads be required to prevent soil slumping and what the estimate dimensions will be (How long? How high?) If the new site is to be located within an existing complex, procure all pertinent and available drawings of the existing units, buildings, and facilities. Procure aerial and ground photographs of the entire site, including adjacent plants or sites, structures, docks, and roads. The ground photographs should be made from two or three directions to define the facility.

1.2. Topography, terrain and soil properties 1.2.1. Obtain soil data on nearby sites, if available. 1.2.2. Obtain data on nearby heavy structures regarding loading, type of foundations, settlement, etc., if available. 1.2.3. Determine if the site’s natural soil has sufficient load bearing capacity to support heavy construction equipment. If not, then determine what type of compacted fill or sand, will be required to prepare the site for construction. Obtain the opinion of local contractors in this regard if possible. 1.2.4. Once the site has been chosen, a follow-up soils investigation will be required. The survey team should determine if reports on soil conditions are available for the site being surveyed through local contractors or land survey offices. Specific information to look for includes borings and soil bearing tests. This information can provide insight into potential construction dif-

Appendix B. Site Selection Data Requirement List

1.2.5. 1.2.6.

1.2.7.

1.2.8.

155

ficulties associated with foundations, underground piping and structures. Determine the quality of the ground water (salt or fresh) and the pH value. Determine the depth to the frost line (if any). Frost penetration for determination of minimum foundation depths and underground piping designs. Also determine the dates for earliest and latest frost recorded. If available, acquire information regarding the potential for inground corrosion of pipes and foundations. Measurements may be available from local contractors, local industry, or land survey firms regarding: 1.2.7.1. Stray electrical ground currents produced up to 20 miles (30 km) away (an example is the electrical current from electrified railways that could cause electrolytic corrosion of buried steel pipe or support piles), 1.2.7.2. Experience using cathodic protection in the area around or on the new site. Determine if excavation will require sheet pilings or well point systems. Local contractors or inspectors may have information regarding how excavation work is presently performed in the area.

1.3. Site Specific Meteorological and Geological Data Whenever possible, meteorological data collected should be based on records covering a period of ten years. The specific items listed below are needed for various design purposes. It is also useful to collect specific records for certain climatic conditions to provide a clearer picture on the extremes for the area. For example, develop a plot of daily maximum and minimum temperatures for a calendar year. For air temperature and humidity, what might be termed “average extremes” is more significant than absolute extremes. In all cases, give the source of data and specify where the data was recorded relative to the site for the following. 1.3.1. Elevation Above Mean Sea Level for the site measured in feet or meters. This is used for calculating atmospheric pressure at the site. 1.3.2. Temperature conditions for the site. These are available from the US Department of Commerce or local weather stations. Temperatures of interest include:

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Guidelines for Facility Siting and Layout

1.3.2.1. 1.3.2.2. 1.3.2.3.

1.3.2.5.

1.3.3. 1.3.4.

1.3.5.

Annual Average Temperature (used in air cooler design and insulation thickness calculations) Coldest Month Average Temperature (used in heating design work) Lowest One-Day Mean Temperature (used in calculating minimum metal design temperatures for pressurized equipment) 1.3.2.4. Extreme Low Temperature (used in design of weather protection requirements) Heating and Cooling Criteria (Summer Wet Bulb and Dry Bulb Temperatures, and Winter Dry Bulb Temperature) for the site. Gather the average readings for each

Humidity month. Wind Conditions from local weather stations or ANSI A58.1 (for USA locations) which include the following data points: 1.3.4.1. Basic Wind Speed (Table A-7 of ANSI A58.1) (used for design of structures, buildings, pressure vessels, piping, storage tanks, air coolers, cooling towers, and stacks) 1.3.4.2. Mean Wind Velocity (used for air pollution calculations, stack considerations, and insulation thickness requirements) 1.3.4.3. Prevailing Wind Direction—generally in the form of a wind rose indicating the percent of time the wind blows in 16 radial directions (N, NNE, NE, ENE, E). An analysis by season is most useful. This information is needed for developing environmental impact assessment, stack designs, flare designs, flare locations, cooling tower designs, air quality control, risk assessment, and equipment locations. Precipitation categories including: 1.3.5.1. Rainfall usually given as 10 year average and maximums for one month, 24 hours, one hour and 30 minutes (this information is used in determining drainage system and water treating system designs capacities) 1.3.5.2. Maximum Snow Load based on local code design requirements (used in building roof designs, structural platform design, and storage tank designs)

Appendix B. Site Selection Data Requirement List

1.3.5.3. 1.3.6.

1.3.7.

157

Ice load if available can be useful in design of structures and buildings.

Severe weather conditions by season that may cause interruption of plant operation including the following information: 1.3.6.1.

Is area subject to fog? If so, what are the frequency and intensity of fog alerts?

1.3.6.2.

Tornados—frequency and worse case recorded severity

1.3.6.3.

Hurricanes or typhoons—frequency and historic worse case scenarios (maximum winds and rain fall

1.3.6.4.

Floods—including dates, total rainfall, and flood depth at the site. If there is a flood control organization for the area, determine who is responsible for maintenance and operation of the flood control equipment (locks, pumps, and levee)? Has there been a flood model developed for the area and has it been validated?

1.3.6.5.

Drought—recorded history should be collected to determine the water availability during a drought and impact on the area from the plant in a drought situation.

1.3.6.6.

Dust Storm—activity, frequency, and records of previous storms.

1.3.6.7.

Lightning strike frequency, which is useful in the design of lightning protection for processing and storage tank facilities.

Is the area subject to earthquakes? If so, what design and seismic coefficient is used by local authorities or structural engineers? (In the U. S., five percent of the dead load is applied horizontally at the center of gravity for an earthquake Zone 1.)

2. TRANSPORTATION ISSUES 2.1. Product and Material Handling 2.1.1.

Describe in detail the anticipated methods of bringing feedstock into the site and distributing products from the site. State the limitations regarding the number and grades of prod-

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2.1.2.

ucts that can be handled by barge, pipeline, tank car, and tank truck. Discuss any laws or regulations governing the handling, shipping, loading, and unloading of products from the site. 2.1.2.1. Will feedstock be required to go into bonded tanks? 2.1.2.2. Will customs inspectors be at the site? 2.1.2.3. Will tanks be gauged or will meter readings be accepted?

2.2. Trucks 2.2.1. Describe the highways and roads in the locality. Can the existing highway handle the anticipated construction loads and the increased traffic loads? 2.2.2. Will a new road have to be built to connect the site with the local highway system? 2.2.3. Determine the maximum allowable loading on roads and bridges. 2.2.4. Estimate the distance to nearest express and freight yard. 2.2.5. Are there any restrictions or curfews on the use of the roads? 2.2.6. Can local roads accommodate the width required for trucks, including for making right turns? 2.2.7. What are the pertinent regulations on ownership and use of passenger and truck vehicles in the area? 2.2.8. What public transport is available to and from the site? 2.2.9. What private trucking services are available? 2.3. Pipelines 2.3.1. If pipelines are required for feedstock or products, submit information on the following. 2.3.1.1. Determine the preferred route and entry into the site. 2.3.1.2. Are there right-of-way requirements (must be considered in total land area required for the site)? 2.3.1.3. Should lines be buried or aboveground? 2.3.1.4. What regulations apply to pipelines? What are the local minimum clearance requirements from roads and highways? If buried, the depth required? 2.3.1.5. Are there any unusual problems, such as rock excavation, quicksand, or corrosion protection?

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159

2.4. Railroads 2.4.1. Furnish copies of any regulations covering permissible proximity to tanks or existing site equipment including operating units. 2.4.2.

Obtain copies of regulations regarding LPG, toxic gases or liquids, etc.

2.4.3.

Determine the names and types of railroads (electric, diesel, steam) serving the potential site area.

2.4.4.

Length of spur that would have to be constructed to the site.

2.4.5.

Submit drawings showing proximity and extent of marshalling facilities.

2.4.6.

Determine the gauge of track in the area, spacing of tracks, and weight of rails. Submit a sketch showing design of rails and railroad ties (wood or concrete) that should be used within the site.

2.4.7.

Determine the minimum clearance for railroads between tracks, from structures, and overhead.

2.4.8.

Determine the normal platform height and clearance between car and platform or building for loading and unloading.

2.4.9.

Obtain the normal load-carrying capacity of rail cars that may be required during construction and/or for shipping product. (both by weight and by volume).

2.4.10. Maximum axle loading permitted on rail cars. 2.4.11. Furnish outline drawings with dimensions of cars handling special materials such as catalyst, cement, caustic, ammonia, acid, SO2, and the like (list possible items which may be hauled). Give published data and regulations on handling the above. 2.4.12. Obtain a schedule of freight rates. 2.4.13. Discuss arrangements that can be made with the railroad company for trackage inside the site. For example, will the railroad company: 2.4.13.1. Supply material and install trackage? 2.4.13.2. Handle movements of rolling stock with their own locomotive during construction and/or during site operation? 2.4.13.3. Rent the site a locomotive for temporary use during construction? If so, furnish rental rates and charac-

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teristics of rental locomotive (draw bar pull and axle loads). 2.4.13.4. Will the site buy a locomotive for permanent use? If the site purchases a locomotive, can it operate on the railroad company tracks? Are there any limitations or conditions? 2.4.13.5. Will the company or railroad operate the site siding? Who will provide marshalling yards or drill service? 2.4.13.6. If the site must supply a locomotive, how far will the railroad’s locomotive come inside the site gate? And will it push a train to where the site locomotive then handles it? 2.4.14. What is the minimum and maximum number of filled or empty cars that could constitute a direct train from the site siding? How often could the cars be spotted (number of deliveries per day) and what is the average size train? 2.4.15. If necessary, can a locomotive be purchased locally? Can it be maintained and serviced locally? 2.4.16. Will the rail yard spacing be open enough to prevent creation of a congested potential explosion scenario? 2.5. Marine Facilities 2.5.1. Information regarding feedstock and products shipments may be site location sensitive and affect the viability of a specific site. 2.5.1.1. How many and what type of vessels will be required to move feedstock and products (including oceangoing tankers of various types, coastal tankers, barges, or bunkering vessels). 2.5.1.2. What is the size (length, draft, and beam) of typical available vessels that might be employed? 2.5.1.3. What specific requirements will need to be provided by the new site to support the vessels, for example, ballast water or bunkering systems? 2.5.2. Furnish pertinent information (published data, if available) on: 2.5.2.1. Current measurements. 2.5.2.2. Soundings. 2.5.2.3. Tides and/or flood conditions. 2.5.2.4. Traffic conditions.

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161

2.5.2.5. Silting conditions and type of harbor bottom. 2.5.2.6. Type of harbor bottom 2.5.2.7. Dredging. 2.5.2.8. Bulkheads. Tidal information should include yearly average high and low and extreme high and low tides on record with discussion of meteorological conditions causing the extremes. Include a copy of tide tables for the area, if available. 2.5.3.

Supply map of harbor showing harbor boundaries, pier head lines, channels, soundings, and river velocity.

2.5.4.

Is protection (such as traveling screens) required against harbor debris?

2.5.5.

Marine Accommodations, Regulations 2.5.5.1.

Describe the port facilities. What draft, length, and beam ships or barges can be accommodated?

2.5.5.2.

Describe the site docking facilities if available? What space is available for piers or docks? Are any alterations desirable? Will a harbor basin need to be constructed?

2.5.5.3.

What are the waterway conditions: details regarding harbor boundaries, channels, soundings, current measurements, tides and flood conditions, tidal waves, and peak waves from storms.

2.5.5.4.

If there are any government-owned or other marine facilities which will be utilized by the company, furnish a complete description, outline basis on which company will rent them, and give design stresses, allowable pull on bollards, and details of dock construction.

2.5.5.5.

Discuss availability of, regulations regarding, and need for tugboats.

2.5.5.6.

What are the pilot regulations and how will the site accommodate the regulations?

2.5.5.7.

Any regulations on clearances between adjacent tanks or barges at piers or with regard to onshore buildings? For example, can barges be loaded sideby-side?

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Guidelines for Facility Siting and Layout

2.5.6.

2.5.5.8.

Estimate average demurrage associated with awaiting tide, fog, weather conditions, or any other factors.

2.5.5.9.

If required, is steam, electric power, or firewater available at the piers or barge sites? If so, in what quantities?

Cargo Handling 2.5.6.1.

Are barges available for construction purposes? What is the maximum size and weight vessel that can be handled by barge? By railroad? By truck via highway? 2.5.6.1.1. ___________ Diameter 2.5.6.1.2. ___________ Length 2.5.6.1.3. ___________ Weight

2.5.7.

2.5.6.2.

What facilities are available for unloading and storing construction materials and equipment? How will ships’ stores be handled, if required? Fresh water? Crew amenities?

2.5.6.3.

Submit information on cargo-handling facilities available, such as floating cranes, lighters, stevedoring charges.

2.5.6.4.

Are there any regulations as to hours when tankers or barges can enter or leave, or during which they can unload or load? What are the demurrage charges?

2.5.6.5.

Is railroad siding available near the dock?

Marine Repair Facilities 2.5.7.1.

What marine repair facilities are available in the vicinity?

2.6. Special Transportation Requirements 2.6.1.

Where is the nearest cargo and passenger airport? What is the distance to the site?

2.6.2.

What is the availability and prospect for using helicopter transport to the site?

2.6.3.

Describe in detail the manner in which material will be handled from shipside direct to the site, from shipside via highway to the site, or from railroad to the site.

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163

3. UTILITIES 3.1. Water Supply 3.1.1. Give volume available from various sources and types such as: 3.1.1.1.

Salt.

3.1.1.2.

Brackish.

3.1.1.3.

Fresh.

3.1.1.4.

Well.

3.1.1.5.

Municipal supply (particularly for drinking, boiler makeup, and firewater)

3.1.2.

Provide daily water temperatures for the hottest month and monthly temperature ranges for the balance of the year.

3.1.3.

If available, furnish analyses of water from each possible source of supply, including hardness, suspended solids, pH value, and amount of corrosive agents. Determine if the water will require chemical protection against algae.

3.1.4.

If water wells are to be drilled, determine information for: 3.1.4.1.

Whether there are regulations limiting the amount or use of well water.

3.1.4.2.

Aquifer water pressure to determine if the water wells will be free flowing, at the pressure and volume required.

3.1.4.3.

Depth to the aquifer.

3.1.4.4.

Allowable spacing between adjacent water wells.

3.1.5.

What is the cost of municipal water? What is the maximum amount of municipal water that may be purchased?

3.1.6.

Local regulations on water supplies for drinking.

3.1.7.

Local practice regarding height and protection from air pollution for water towers or standpipes.

3.2. Steam Supply 3.2.1. Is steam available from sources outside the site? If so, at what pressures, quantities, and cost? 3.2.2.

If steam is purchased, furnish drawings showing location of steam plant in relation to the planned site.

3.2.3.

Will an outside source utilize fuel or burnable waste products generated by the new site?

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Guidelines for Facility Siting and Layout

3.2.4.

3.3. Fuel 3.3.1. 3.3.2. 3.3.3.

4.

Are there any rules, regulations, or standards that may apply for steam plant construction. These may include piping, boilers, exhaust systems, and condensate handling. Determine the availability, reliability, supply points, heating values, costs, and analysis of fuel commonly used in the area. Determine supply facilities, pressures, temperatures, and fuel specifications, if available. Determine the needed fuel supply facilities (storage tanks, pipelines, and unloading facilities).

ELECTRICAL AND COMMUNICATION SYSTEMS

4.1. Electrical Systems 4.1.1. Name and address of the utility. Name and position of person(s) to contact there for information. 4.1.2. Present and future power availability and reliability. 4.1.3. Applicable rate schedules, including fuel adjustment clauses, demand charges, labor and power factor clauses, government taxes, and contract duration. 4.1.4. Is it permissible to generate all or a portion of its power requirements with the public utility system providing the balance? What are the rates and charges for provision of both partial and full standby power for in-plant generation? 4.1.5. Will the new site or the utility will be responsible for providing the main substation facilities, including real estate and civil work? 4.1.6. Applicable investment charges for site utility-installed facilities. 4.1.7. Type and voltage level of the utility service feeders, and whether the feeders will be radial or loop type. Where the radial feed system is to be installed, will the utility install two independent feeders? 4.1.8. Maximum and minimum interrupting level (kVA or MVA) of incoming service. 4.1.9. Type and main substation transformers to be installed, and whether transformers will have automatic load tap changers or manual no-load tap changers.

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165

4.1.10. Availability of construction power, the applicable rate schedules, and the necessary facilities to be provided. 4.1.11. Maximum allowable voltage-drop on motor starting or group reacceleration. 4.1.12. Regarding public utility power, determine: 4.1.12.1. Amount available: ____________ kW 4.1.12.2. Characteristics: ____________ phase 4.1.12.3. ____________ cycle 4.1.12.4. ____________ volts 4.1.13. What is the minimum and future maximum short circuit level kVA at the source and/or the adjacent site (s) that will be sharing the utility power? 4.1.14. Reliability of power supply based on past performance (unplanned outages per year, planned outages per year, length of outages, and percent voltage variation) 4.1.15. What is the distance from the new site property limits to substation(s) from which utility would supply power? 4.1.16. How many feeders would the utility install from substation(s) to the new site limits? 4.1.17. What are the feeder characteristics regarding construction method? Are feeders underground or overhead? 4.1.18. Would the new site have exclusive use of feeders? 4.1.19. If feeder voltage were too high for the new site, would the cost of this substation be borne by the utility or the new site? 4.1.20. What voltage will the new site require for: 4.1.20.1. Lighting 4.1.20.2. Small motors [below ____________ kW (hp)] 4.1.20.3. Large motors [above ____________ kW (hp)] 4.1.21. What are the nominal standard secondary distribution voltages available in the range of 400 volts to 11,000 volts? 4.1.22. Local power distributor equipment. 4.1.23. What are the characteristics of available power transformers as to: 4.1.23.1. Voltage ratings and sizes in the 300kVA to 2,500-kVA range? 4.1.23.2. Impedance of various sizes and ratings? 4.1.24. What are characteristics of available switchgear as to:

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Guidelines for Facility Siting and Layout

4.1.24.1. Standard voltage ratings in the 400-volt to 11,000volt range? 4.1.24.2. Continuous current, interrupting current, and momentary current ratings of various-sized circuit breakers? 4.1.25. Will the public utility provide power during construction? 4.2. Communication Systems 4.2.1. Telephone systems—Provide the following information. 4.2.1.1. Describe local system as to type (manual or automatic) and adequacy to handle increased traffic. 4.2.1.2. Give information on rental rates and opinion as to advisability of installing a site-owned intra-site telephone system or renting a system installed and owned by the telephone company. If rental basis is feasible, would it include private, automatic or manual, exchange switchboard, cable plant, and instruments? What facilities would have to be provided by the site? 4.2.2. Internet Systems—Determine what internet communication support is available: phone lines, broadband, cable, ISDN. 4.2.3. Microwave Communications—Are microwave systems required due to the lack of telephone and internet support? 4.2.4. Radio communications—What laws govern its use? Are there available frequencies? What other users could provide interference? How secure are the channels? 4.2.5. Mail—Is there mail service or will the site have to develop its own service? How far is the nearest mail service?

5.

ENVIRONMENTAL CONTROLS

5.1. Wastewater Quality Control 5.1.1. What governmental regulation is in effect that must be applied to industrial wastes and the quality of the effluent discharged into natural water bodies? 5.1.2. Are there any similar regulations for sanitary sewage? 5.1.3. Obtain copies of regulations that apply to both industrial wastes and sanitary sewage. In addition, obtain copies of approved designs of sanitary sewage treatment facilities.

Appendix B. Site Selection Data Requirement List

5.1.4.

167

Furnish data giving pertinent information regarding local and state regulations for all types of buildings regarding sanitary and plumbing requirements. 5.1.5. If such copies cannot be obtained, the following information should be sought from proper sources. 5.1.5.1. What degree of treatment is specified for sanitary sewage? 5.1.5.2. What quality standards are imposed on sanitary sewage and industrial wastewater effluents? 5.1.5.3. Will septic tanks be permitted for remote areas, for a small number of occupants? Is there a point where septic tanks are not permitted and other, moreexpensive methods of disposal required? 5.1.6. What agency enforces the regulations and what is the organization of the agency? 5.1.7. In the event that waste discharge is not controlled by definitive legal measures enforced by an official body, is there any governmental control, local or otherwise, and what is the extent of this control? 5.1.8. What is the general trend regarding waste discharge control? 5.1.8.1. What is the attitude of the control officials? 5.1.8.2. Is there any indication that existing regulations will be tightened or new regulations adopted where none exist at the moment? 5.1.9. What natural water body will receive the wastewater effluent from the new site? 5.1.9.1. Obtain quantitative and qualitative data on seasonal flow if discharge is to a stream. 5.1.9.2. Obtain information on currents and tidal variations if discharge is to a lake or harbor. 5.1.10. Are the natural receiving water bodies contaminated at present? If so, to what extent? 5.1.11. Give locations of the following with respect to the site: 5.1.11.1. Commercial fishing areas 5.1.11.2. Recreational areas for swimming, boating, or fishing 5.1.11.3. Residential areas 5.1.11.4. Domestic and industrial water supply intakes downstream of the proposed facilities.

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Guidelines for Facility Siting and Layout

5.1.12.

5.1.13.

5.1.14. 5.1.15. 5.1.16. 5.1.17. 5.1.18.

5.1.19.

5.1.20.

5.1.11.5. Municipal sewage and industrial waste treatment plant outfalls both upstream and downstream of the proposed facility If available, provide analytical data (sufficient to show seasonal variation) on receiving water as listed: 5.1.12.1. Temperature 5.1.12.2. Turbidity 5.1.12.3. Color 5.1.12.4. Suspended solids 5.1.12.5. Odor—concentration of concern 5.1.12.6. Dissolved solids 5.1.12.7. Dissolved oxygen 5.1.12.8. Chemical and biochemical oxygen demand 5.1.12.9. Total sulfur 5.1.12.10. Oil content 5.1.12.11. Phenol content 5.1.12.12. Acidity, alkalinity, pH What is the attitude of the general public towards waste disposal control as reflected by civic group activity and newspaper publicity? Is local industry organized into a group for exchange of information on water contamination? Do any national technical groups exist which have an interest in water contamination control? Could sanitary sewage from the new site be discharged to municipal sewers? Could sludge from sanitary sewage treatment be disposed of through local companies? Describe existing sanitary sewerage and drainage systems in the area of the new site. Provide the size of main lines and the proximity of main lines to the site. Identify potential means of disposing of site effluent (dirty process water and sanitary sewage) and storm water. Consider the level of contamination and that the source of cooling waters should not be affected by the site effluent. Is it permissible to discharge clean storm water without treatment?

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169

5.1.21. What degree of treatment is specified for industrial wastewater? 5.1.22. What water quality standards are imposed on industrial wastewater effluents? Are effective water standards controlled by receiving water quality or by discharge effluent quality? 5.1.23. What requirements are there regarding submission of plan for treatment facilities for approval of control authorities? 5.1.24. What requirements are there for permits, and where they are obtained, for operation of approved treating facilities. 5.1.25. What requirements are there for qualification by test of treatment plan performance? 5.1.26. What requirements are there by control authorities for submission of treatment plant operating reports and the data to be provided? 5.1.27. Are there regulations specifying analytical methods to be used in determining the level of specific impurities in the effluent, including hydrocarbon or toxic materials content? 5.1.28. Are penalties included in those regulations, the method of assessment, and recourse available to the owner or operator? 5.1.29. Assess general governmental trends regarding wastewater control. If there is any indication that existing regulations will become more restrictive, or that new regulations will be adopted, obtain a forecast or timetable. 5.1.30. Assess the impact from off-site water effluent by determining the following: 5.1.30.1. Determine which natural body of water will receive the drainage and wastewater effluent from the site. 5.1.30.2. Can natural drainage from adjacent areas be diverted around the site, or must it be treated as storm water entering the site? 5.1.30.3. What are the water quality criteria for the receiving water? 5.1.30.4. In the case where receiving water is a stream, acquire quantitative and qualitative data on seasonal flow if available. The data should reflect seasonal variations in receiving water quality for all parameters used in evaluating effluent discharge quality.

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5.1.30.5. In the cases of lakes or harbors, information on currents and tidal variations or lake water elevations is desirable. 5.2. Air Quality Control 5.2.1. What are the national, state, and local regulations in effect for discharge of sulfur oxides, particulate matter, carbon monoxide, photochemical oxidants, hydrocarbons, nitrogen dioxide, other applicable chemicals, and odors? Obtain a copy of relevant regulations with the latest addenda, if available. 5.2.2. If a copy of these regulations cannot be obtained, the following questions should be answered. 5.2.2.1. What are permissible limits of pollutants such as sulfur dioxide, solids, smoke, and others that can be discharged to the atmosphere? 5.2.2.2. What control, if any, governs the height of industrial stacks? 5.2.2.3. What is the average height of industrial stacks in the general vicinity? 5.2.2.4. Must plans for air control facilities be submitted to control authorities for approval? 5.2.2.5. What penalties are included in the regulations, how are they assessed, and what legal recourse does the accused have? 5.2.2.6. What is the process for and time required to obtain a waiver or exception? 5.2.2.7. Are operating permits required to run air quality control equipment? 5.2.3. What agencies enforce regulations? Outline their organizations. How is the law enforced? What are the powers of control officers? Where air quality is not regulated by the central government, to what extent does the local government control emissions? 5.2.4. In the event that air contamination is not controlled by definitive measures enforced by an official body, is there any governmental control, local or otherwise, and to what extent? 5.2.5. What is the general governmental trend regarding air contamination control? 5.2.5.1. What is the working relationship with the control officials?

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5.2.5.2.

5.2.6. 5.2.7. 5.2.8. 5.2.9. 5.2.10.

5.2.11.

5.2.12. 5.2.13. 5.2.14.

Is there any indication that existing regulations will be tightened or new regulations adopted where none exist at the moment? What is the perception of the general public toward air contamination as reflected by civic groups and newspaper publicity? Is local industry organized into a group for exchange of information on air contamination and air quality control? Do any national technical groups exist which have an interest in air contamination control? What is the nature of industrial emissions to the atmosphere near the site? Obtain data on existing levels of atmospheric pollutants such as sulfur dioxide, dust falls, hydrogen sulfide, and smoke. Odor should be included. Example: Concentration of dust particles: _________ ppm (normal); _________ ppm (maximum). In relation to the new site, give the location and proximity of the following: 5.2.11.1. Residential areas 5.2.11.2. Schools 5.2.11.3. Prisons 5.2.11.4. Farming areas. 5.2.11.5. Hospitals 5.2.11.6. Resorts. 5.2.11.7. Business areas. 5.2.11.8. Manufacturing areas. 5.2.11.9. Public parks. 5.2.11.10. National treasures or landmarks 5.2.11.11. Airports. Are there any special topographical features such as nearby hills or valleys that can affect dispersal of air pollutants? What are the requirements for vapor recovery in tank loading operations? Is a standby supply of low-sulfur plant fuel required should an air pollutant alert or emergency occur?

5.3. Sanitary Sewage Collection and Treatment 5.3.1. Obtain regulations regarding collection and treatment of sanitary sewage.

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5.4. Noise and Luminosity Level Design Limitations 5.4.1.

Determine if noise levels are regulated in the area. If so, collect data on the current noise levels for day and night levels.

5.4.2.

Determine if luminosity levels are regulated in the area. If so, collect data on the current levels.

5.4.3.

Does the site have hills or trees or other features to block the light from the site?

6. FIRE, SAFETY, AND SECURITY 6.1. Fire and Safety 6.1.1.

Describe local firefighting facilities. Obtain drawings of nearest municipal fire mains showing size, capacity, and pressure. Indicate the location of firefighting facilities relative to the site.

6.1.2.

What regulations govern the provision of firefighting equipment for tankage or other site facilities?

6.1.3.

What emergency services are available in the area? 6.1.3.1.

Hospital

6.1.3.2.

Medical Clinic

6.1.3.3.

Burn Center

6.1.3.4.

Ambulance

6.1.3.5.

Air lift to major medical centers

6.1.4.

What is the quality of the emergency services?

6.1.5.

Are shared services available from the complex or adjacent sites?

6.1.6.

Does the road structure permit good emergency access to the site?

6.2. Security 6.2.1.

What local police protection is available in the surrounding area, at the docks, and near the refinery site?

6.2.2.

To what extent can the local police or shared site security be used on a construction project and when the site is developed?

6.2.3.

Will fences and additional guards be needed at the site?

6.2.4.

Is there much pilfering done in the area?

Appendix B. Site Selection Data Requirement List

7.

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SITE FEATURES

7.1. Personnel 7.1.1. Engineering Firms 7.1.1.1. List firms available to handle site construction engineering work for: 7.1.1.1.1. Soil investigation 7.1.1.1.2. Process Units’ construction 7.1.1.1.3. Utilities construction 7.1.1.1.4. General Facilities (buildings or, roads) 7.1.1.1.5. Dock, Marine, Wharf Terminal Facilities 7.1.1.2. To what extent are these firms familiar with internationally accepted practices and standards (for instance, ANSI standards)? What similar jobs have they performed? For whom have they performed these jobs? How many people are employed? 7.1.2. Contractors 7.1.2.1. List firms that will be available locally to handle: 7.1.2.1.1. Site preparation (hydraulic fill or earthmoving) 7.1.2.1.2. Erection of tankage 7.1.2.1.3. Dock and terminal facilities 7.1.2.1.4. General field labor contracts for process and offsite work 7.1.2.1.5. Housing, buildings 7.1.2.2. To what extent can the site organization handle construction supervision? 7.1.2.3. Identify any laws governing the use of foreign or expatriate contractors. 7.1.2.4. Are any of these contractors or engineering firms affiliated with international engineering and construction firms? 7.1.3. Construction and Maintenance Labor 7.1.3.1. Obtain estimates for the cost of construction at the site. Examples may be available from local contractors or adjacent sites. These may include the cost of civil work, site preparation, tank erection, and buildings of different construction.

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7.1.3.2.

7.1.3.3. 7.1.3.4.

7.1.3.5. 7.1.3.6. 7.1.3.7. 7.1.3.8. 7.1.3.9.

For each of the following crafts, what are the availability of skilled craftsmen and is there a history of labor issues impacting cost and schedule? 7.1.3.2.1. Common labor 7.1.3.2.2. Carpenters 7.1.3.2.3. Bricklayers. 7.1.3.2.4. Welders (acetylene) 7.1.3.2.5. Welders (electric) 7.1.3.2.6. Pipe fitters 7.1.3.2.7. Boilermakers 7.1.3.2.8. Structural ironworkers (riveters) 7.1.3.2.9. Cement workers 7.1.3.2.10. Electricians 7.1.3.2.11. Instrument men 7.1.3.2.12. Insulators 7.1.3.2.13. Crane operators 7.1.3.2.14. Truck drivers 7.1.3.2.15. Mechanics 7.1.3.2.16. Machinists 7.1.3.2.17. Painters 7.1.3.2.18. Plumbers 7.1.3.2.19. Riggers Will a premium need to be paid to attract workers to the area? Discuss availability and source of supervisors and foremen. What amount of outside (of the area) supervision will be required? What is the estimated optimum ratio of outside (of the area) to native labor for site construction work? Will it be necessary or desirable to establish training programs in the crafts required for construction work? Are there any racial problems or discrimination that need to be taken into account? What percentages of local workers speak or understand English? Review the cost records of other large local projects to get an idea of productivity.

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175

7.1.3.10. Is night work permitted? 7.1.4.

Operations Personnel 7.1.4.1.

7.1.4.2.

Discuss the availability of people required for the permanent site staff in categories such as the following: 7.1.4.1.1. Support staff (Accountants, clerks, draftsman, typists) 7.1.4.1.2. Engineers (process, mechanical, civil) 7.1.4.1.3. Laboratory assistants 7.1.4.1.4. Process operators 7.1.4.1.5. Doctors and nurses 7.1.4.1.6. Police 7.1.4.1.7. Craftsmen (see craft listing above) To what extent will permanent housing be required for employees? Where will this housing be located?

7.1.4.3.

To what extent can personnel speak and write the language used for site labeling and documentation?

7.1.4.4.

What languages are used?

7.2. Housing 7.2.1. For remote sites, is housing available for construction personnel? And for site employees? 7.2.2.

Are other features available such as schools, shops, and recreational facilities?

7.3. Site Support Facilities 7.3.1. List the prices of heavy construction equipment and tools that can be made available by the site organization, local contractors, or manufacturers. Are guy derricks available locally? 7.3.2.

What is the rental cost for such equipment? Is the operator included? Are qualified operators available for the equipment?

7.3.3.

Are garage services and spare parts available locally for international equipment?

7.3.4.

Are there any restrictions against the use of heavy mechanical equipment?

7.3.5.

Shop Facilities 7.3.5.1.

To what extent can site maintenance work be handled by outside contractors?

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7.3.6.

7.3.5.1.1. What type and class of work can be done by outside shops? 7.3.5.1.2. What is the location of outside shops relative to the site? 7.3.5.1.3. What is the local manpower availability for turnaround work? Construction Materials and Equipment 7.3.6.1.

Indicate the quantities and types of construction materials that are locally available, for example, what facilities are available locally for mixing concrete?

7.3.6.2.

Are any of these materials available as surplus in nearby affiliate sites?

7.3.6.3.

What restrictions are there on importing any of these materials and other site equipment such as pumps, exchangers, drums, towers, and motors? Are any of the latter made locally?

7.3.6.4.

Is warehouse space for materials available or must this be erected?

7.3.6.5.

What material and equipment required for construction can be purchased locally. Are foundries, boiler shops, machine shops, and steel fabricating facilities available locally, and in what capacity?

7.3.6.6.

What governmental restrictions, regulations, priorities, or allocation supply may impact availability of goods?

7.3.6.7.

Provide information on the availability and method of supply for various materials required for site operation and maintenance, particularly chemicals for example: 7.3.6.7.1. Ammonia. 7.3.6.7.2. Calcium chloride. 7.3.6.7.3. Inhibitors. 7.3.6.7.4. Nitrogen 7.3.6.7.5. Oxygen. 7.3.6.7.6. Sodium carbonate. 7.3.6.7.7. Sodium hydroxide. 7.3.6.7.8. Sulfuric acid 7.3.6.7.9. Etc.

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8. SYSTEMS OF MEASUREMENT 8.1. What system of measure will be used for calibrating instruments? (Metric?) 8.2. What weights and measures system is used in area or site? 8.3. What system of measure will be preferred by local inspectors and local engineering firms to develop and approve construction drawings? 8.4. What system of measure is likely to be preferred locally for site instrumentation, drawing and procedure development?

9. CODES, STANDARDS, DESIGN FACTORS, UNITS 9.1. Furnish copies of any local codes or regulations which must be followed with regard to: 9.1.1. Structural steel and reinforced concrete 9.1.2.

Architectural design

9.1.3.

Pressure vessels

9.1.4.

Electrical design

9.1.5.

Piping

9.1.6.

Boilers

9.1.7.

Plumbing and sanitary facilities (architectural)

9.1.8.

Working conditions such as air changes, working temperatures in building, or safety requirements

9.1.9.

Spacing of process units, tank firewall capacity, and sewer connections

9.1.10. Permissible noise level. What is present noise level in decibels? 9.1.11. Health ordinances 9.2. Are the following American standards applicable in place of the corresponding local codes? 9.2.1. NFPA: For site design, tank spacing, and layout 9.2.2.

API, ASME: For pressure vessels and tanks

9.2.3.

Joint Committee for Specifications on Reinforced Concrete: for foundations

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Guidelines for Facility Siting and Layout

9.2.4.

American Institute of Steel Construction Code: For structural steel

9.3. What are local approval requirements for building designs? Identify the prevailing type of architecture and typical materials of construction. Are codes applicable for temporary constructions? 9.4. Can imported steel be used instead of steel made to local specifications? Obtain booklets on local shape, weight, and standard sizes. State whether Bessemer or open-hearth steel will be required. 9.5. Are there any local piping preferences, codes or standards which will affect design according to the company standards? 9.6. What is the local regulation or practice regarding wind load used in design? What wind velocity do local authorities require? What snow loads are used in design? 9.7. Is a corrosion allowance used locally in structural steel design? 9.8. Are there any aircraft regulations that would limit the height of structures? Are warning lights required? 9.9. What zoning regulations govern the use of property and the height of flares, structures, and buildings? 9.10. Do regulations permit use of two-way radios in facility and in truck cabs?

References 1. American Chemistry Council, Chlorine Institute, Inc., and Synthetic Organic Chemical Manufacturers Association. 2001. Site Security Guidelines for the U.S. Chemical Industry. American Chemistry Council. 2. American Industrial Hygiene Institute. 1999. Emergency Response Planning Guidelines, 1999 ERPGs Complete Set, Stock No. 359-EA-99. AIHA Press. Fairfax, VA. 3. API RP 521. 1999. Guide for Pressure-Relieving and Depressuring Systems. American Petroleum Institute, Washington D. C. 4. API RP 752. 1995. Management of Hazards Associated with Location of Process Plant Buildings. American Petroleum Institute, Washington D. C. 5. API RP 2001. 1998. Fire Protection in Refineries, American Petroleum Institute. American Petroleum Institute, Washington D. C. 6. API RP 2510. 1995. Design and Construction LPG Installations, Seventh Edition. American Petroleum Institute, Washington D. C. 7. API RP 2510A. 1996. Fire Protection Considerations for the Design and Operation of Liquefied Petroleum Gas (LPG) Storage Facilities, Second Edition. American Petroleum Institute, Washington D. C. 8. Association of Engineering Geologist’s online dictionary 9. Baker, W. E. et al. Explosion Hazards and Evaluations. 1983. Elsevier Scientific Publishing Company, New York. 10. Bartleby.com 11. Cambridge Dictionaries online 12. CCPS (Center for Chemical Process Safety). 1989. Guidelines for Chemical Process Quantitative Risk Assessment. American Institute of Chemical Engineers, New York. 13. CCPS (Center for Chemical Process Safety). 1992. Guidelines for Hazard Evaluation Procedures. American Institute of Chemical Engineers, New York. 14. CCPS (Center for Chemical Process Safety). 1993. Guidelines for Engineering Design for Process Safety. American Institute of Chemical Engineers, New York. 15. CCPS (Center for Chemical Process Safety). 1993. Guidelines for Auditing Process Safety Management Systems. American Institute of Chemical Engineers, New York. 16. CCPS (Center for Chemical Process Safety). 1994. Guidelines for Evaluating the Characteristics of Vapor Cloud Explosion, Flash Fires, and BLEVEs. American Institute of Chemical Engineers, New York. 179

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17. CCPS (Center for Chemical Process Safety). 1995. Guidelines for Process Safety Documentation. American Institute of Chemical Engineers, New York. 18. CCPS (Center for Chemical Process Safety). 1995. Guidelines for Process Safety Fundamentals in General Plant Operations. American Institute of Chemical Engineers, New York. 19. CCPS (Center for Chemical Process Safety). 1995. Guidelines for Safe Storage and Handling of Reactive Materials. American Institute of Chemical Engineers, New York. 20. CCPS (Center for Chemical Process Safety). 1995. Guidelines for Technical Management of Chemical Process Safety. American Institute of Chemical Engineers, New York. 21. CCPS (Center for Chemical Process Safety). 1995. Guidelines for Chemical Transportation Risk Analysis. American Institute of Chemical Engineers, New York. 22. CCPS (Center for Chemical Process Safety). 1996. Guidelines for Evaluating Process Plant Buildings for External Explosions and Fires. American Institute of Chemical Engineers, New York. 23. CCPS (Center for Chemical Process Safety). 1996. Inherently Safer Chemical Processes: A Life Cycle Approach. American Institute of Chemical Engineers, New York. 24. CCPS (Center for Chemical Process Safety). 1998. Guidelines for Pressure Relief and Effluent Handling Systems. American Institute of Chemical Engineers, New York. 25. CCPS (Center for Chemical Process Safety). 1999. Guidelines for Consequence Analysis of Chemical Releases. American Institute of Chemical Engineers, New York. 26. CCPS (Center for Chemical Process Safety). 2000. Guidelines for Chemical Process Quantitative Risk Assessment. American Institute of Chemical Engineers, New York. 27. CCPS (Center for Chemical Process Safety). 2001. Guidelines for Layers of Protection Analysis. American Institute of Chemical Engineers, New York. 28. CCPS (Center for Chemical Process Safety). 2002. Guidelines for Analyzing and Managing Security Vulnerabilities of Fixed Chemical Sites. American Institute of Chemical Engineers, New York. 29. CCPS (Center for Chemical Process Safety). 2003. Guidelines for Fire Protection in Chemical, Petrochemical, and Hydrocarbon Processing Facilities. American Institute of Chemical Engineers, New York. 30. CCPS (Center for Chemical Process Safety). 2003. Understanding Explosions. American Institute of Chemical Engineers, New York. 31. Chemical Safety Board. 1999. “Bhopal Disaster Spurs U.S. Industry, Legislative Action.” http://www.chemsafety.gov/lib/bhopal01.htm 32. Control of Major Accident Hazards Regulations 1999 (COMAH). Health and Safety Executive, U.K.

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33. Department of the Environment. 1990. Planning Controls over Hazardous Development. U.K. 34. Dictionary.com 35. Encyclopedia.com 36. Factory Mutual Insurance Corporation. 2000. FM Global Property Loss Prevention Data Sheets 7-80 Organic Peroxides. 37. Factory Mutual Insurance Corporation. 1998. FM Global Property Loss Prevention Data Sheets 7-81 Organic Peroxides Hazard Classification. 38. Factory Mutual Insurance Corporation. 2000. FM Global Property Loss Prevention Data Sheets 7-82N Storage of Liquid and Solid Oxidizing Materials. 39. Harcourt.com 40. Health and Safety Executive. 1989. Risk Criteria for Land-Use Planning in the Vicinity of Major Industrial Hazards. HMSO, London. 41. Health and Safety Executive. 2002. Level 3 Guidance for the Assessment of the Technical Aspects of COMAH Safety Reports. http://www.hse.gov.uk/hid/land/comah/level3/5a59323.htm http://www.hse.gov.uk/hid/land/comah/level3/5c9a15b.htm 42. The Institution of Chemical Engineers (IChemE), and the International Process Safety Group (IPSG). 1995. Inherently Safer Process Design. The Institution of Chemical Engineers, Rugby, England. 43. IP Model Code of Safe Practice for the Petroleum Industry: A risk-based approach to hazardous area classification.1998. Institute of Petroleum, U.K. 44. IRI IM.2.5.2. Plant Layout and Spacing for Oil and Chemical Plants. Industrial Risk Insurers Hartford, CT. 45. Jenkins, B. M. and Gersten, L. N. 2001. “Protecting Public Surface Transportation Against Terrorism and Serious Crime: Continuing Research on Best Security Practices”. Mineta Transportation Institute. 46. Kletz, T.A. 1984. Cheaper, Safer Plants, or Wealth and Safety at Work. The Institution of Chemical Engineers. Rugby Warwickshire, England. 47. Kletz, T.A. 1991. Plant Design for Safety. Hemisphere, New York. 48. Las Vegas Review Journal online 49. Lees, F. P. 1996. Loss Prevention in the Process Industries. Second Edition. Elsevier Science Ltd., Oxford, England. 50. LPGA CoP 1 Bulk LPG storage at fixed installation. Part 1: Design, installation and operation of vessels located above ground. 1998. LP Gas Association. U.K. 51. LPGA CoP 1 Bulk LPG storage at fixed installation. Part 4: Buried/mounded LPG storage. 1999. LP Gas Association. U.K. 52. Marsh Risk Consulting. 2001. Large Property Damage Losses in the Hydrocarbon-Chemical Industries— A Thirty-Year Review, Nineteenth Edition. 53. Merriam Webster’s Collegiate Dictionary online 54. NFPA. 1991. Flammable and Combustible Liquids Code Handbook, Fourth Edition. National Fire Protection Association, Quincy, MA.

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55. NFPA 30. 1996. Flammable and Combustible Liquids Code. National Fire Protection Association, Quincy, MA. 56. NFPA 50. 2001. Standard for Bulk Oxygen Systems at Consumer Sites. National Fire Protection Association, Quincy, MA. 57. NFPA 58. 1996. Liquefied Petroleum Gas Code. National Fire Protection Association, Quincy, MA. 58. NFPA 432. 2002. Code for the Storage of Organic Peroxide Formulations. National Fire Protection Association, Quincy, MA. 59. NFPA 496. 1998. Standard for Purged and Pressurized Enclosures for Electrical Equipment National. Fire Protection Association, Quincy, MA. 60. NFPA Fire Protection Handbook. 1976. National Fire Protection Association, Quincy, MA. 61. Perry’s Chemical Engineers Handbook 7th Edition. 1997. Perry, R.H.; Green, D. W.; Maloney, J. O., McGraw-Hill. 62. Province of British Columbia Ministry of Forests online dictionary 63. EPA.gov/rcraonline 64. Scottish Development Department. 1992. Planning Controls over Hazardous Development. U.K. 65. U. S. Department of State. 2000. “Patterns of Global Terrorism— 1999.” 66. U. S. Chemical Safety and Hazard Investigation Board. 2002. “The Explosion at Concept Sciences: Hazards of Hydroxylamine”. National Technical Information Service, Springfield, VA. 67. WBE (Wilfred Baker Engineering). 1998. “Due Diligence Study”. Prepared for Mobil Technology Company. Fairfax, Virginia. 68. Wormuth, D.W. 1985. “BLEVE! The Tragedy of San Jaunico.” Skandia International Insurance Corporation, Stockholm, Sweden.

Glossary

Air Quality Control: The control of the level of pollutants prescribed by regulations that may not be exceeded during a specified time in a defined area. (Association of Engineering Geologist’s online dictionary) Atmospheric tank: A storage tank that has been designed to operate at pressures from atmospheric through 0.5 psig measured at the top of the tank. (NFPA30) Atmospheric dispersion: The low momentum mixing of a gas or vapor with air. The mixing is the result of turbulent energy exchange, which is a function of wind and atmospheric temperature profile. (CCPS, 1999) Autoignition temperature: The minimum temperature at which combustion can be initiated without an external ignition source. (CCPS, 1996, no. 22) Battery Limit: The perimeter of a specific manufacturing process area. It is often defined by the roads around the perimeter. This area will include process equipment, and may include in-process tankage. Blast: A transient change in the gas density, pressure, and velocity of the air surrounding an explosion point. (CCPS, 1994) Blast resistant buildings: Buildings that are structurally designed to withstand an explosion generated load (pressure and impulse) while sustaining a predetermined amount of damage. Blast wave: The overpressure wave traveling outward from an explosion point. (CCPS, 1996, no. 22) BLEVE: A Boiling Liquid Expanding Vapor Explosion is a blast resulting from the sudden release and nearly instantaneous vaporization of a liquid under greater-than-atmospheric pressure at a temperature above its atmospheric boiling point. The material may be flammable or nonflammable. A BLEVE is often accompanied by a fireball if the contained liquid is flammable and its release results from vessel failure. (CCPS, 1996, no. 22) Blowdown drums: Separators or accumulators used to separate liquids and vapors in pressure-relieving and emergency systems. 183

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Brownfield: An industrial or commercial property that is abandoned or underused and being considered as a potential site for redevelopment. (Dictionary .com) Boil over: A violent expulsion of contents caused by a heat wave from the surface burning at the top of the tank reaching the water stratum at the bottom of the tank. Oils subject to boilover contain components having a wide range of boiling points, including both light ends and viscous residues. These characteristics are present in most crude oils. (Draft NFPA Understanding Fire Protection for Flammable Liquids) Combustible liquids: Any liquid that has a closed-cup flash point at or above 100ºF (37.8ºC), as determined by the test procedures defined in NFPA 30. Combustible liquids are classified as Class II or Class III as follows: (a) Class II Liquid. Any liquid that has a flash point at or above 100ºF (37.8ºC) and below 140ºF (60ºC). (b) Class IIIA. Any liquid that has a flash point at or above 140ºF (60ºC), but below 200ºF (93ºC). (c) Class IIIB. Any liquid that has a flash point at or above 200ºF (93ºC). (NFPA 30) Combustion: exothermic chemical reaction with oxygen as a primary reagent. (CCPS, 1996, no. 22) Conceptual design: The initial design of a project when basic parameters are known but design details have yet to be developed. Consequence: The direct, undesirable result of an accident sequence usually involving a fire, explosion, or release of toxic material. Consequence descriptions may be qualitative or quantitative estimates of the effects of an accident in terms of factors such as health impacts, economic loss, and environmental damage. (CCPS, 1995, no. 17) Consequence analysis: The analysis of the expected effects of incident outcome cases independent of frequency or probability. (CCPS, 1999) Cryogenic liquid: A refrigerated liquid gas having a boiling point below –130°F (–90°C) at atmospheric pressure. (NFPA 30) Detection systems: A mechanical, electrical, or chemical device that automatically identifies the presence of a material or a change in environmental conditions such as pressure, temperature, or composition. (Bartleby.com) Dike: An embankment or wall built to act as a barrier blocking passage of liquids to surrounding areas. (Dictionary.com)

Glossary

185

Emergency shutdown (ESD) system: The safety system which overrides the action of the basic control system when predetermined conditions are violated. (CCPS, 1993, no. 14) ERPG: The American Industrial Hygiene Institute defines Emergency Response Planning Guideline (ERPG) levels. • The ERPG-1 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hr without experiencing other than mild transient adverse health effects or perceiving a clearly defined, objectionable odor. • The ERPG-2 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hr without experiencing or developing irreversible or other serious health effects or symptoms which could impair an individual’s ability to take protective action. • The ERPG-3 is the maximum airborne concentration below which it is believed that nearly all individuals could be exposed for up to 1 hr without experiencing or developing life-threatening health effects. Environmental Impact Statement: The analysis of the impact that a proposed development, usually industrial, will have on the natural and social environment. It includes assessment of long- and short-term effects on the physical environment, such as air, water, and noise pollution, as well as effects on employment, living standards, local services, and aesthetics. The National Environmental Policy Act of 1969 as well as many state and local laws enacted during the late 1960s and early 1970s mandate that these statements be completed before major development projects can begin. (Encyclopedia.com) Environmentally Sensitive Areas (ESAs): Areas requiring special management attention to protect important scenic values, fish and wildlife resources, historical and cultural values, and other natural systems or processes. ESAs for forestry include potentially fragile, unstable soils that may deteriorate unacceptably after forest harvesting, and areas of high value to non-timber resources such as fisheries, wildlife, water, and recreation. (Province of British Columbia Ministry of Forests online dictionary) Explosion: A release of energy that causes a pressure discontinuity or blast wave. (CCPS, 1999) Explosion Overpressure: Any pressure above atmospheric caused by a blast. (CCPS, 1994) Facility: A portion of or complete plant, unit, site, complex or any combination thereof.

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Fire: A combustion reaction accompanied by the evolution of heat, light, and flame. (CCPS, 1996, no. 22) Fire protection: Methods of providing for fire control or fire extinguishment. (NFPA 850) Flammable liquids: Any liquid that has a closed-cup flash point below 100ºF (37.8ºC), as determined by the test procedures described in NFPA 30 and a Reid vapor pressure not exceeding 40 psia (2068.6 mm Hg) at 100ºF (37.8ºC), as determined by ASTM D 323, Standard Method of Test for Vapor Pressure of Petroleum Products (Reid Method). Flammable liquids are classified as Class I as follows: (a) Class IA liquids shall include those liquids that have flash points below 73ºF (22.8ºC) and boiling points below 100ºF (37.8ºC). (b) Class IB liquids shall include those liquids that have flash points below 73ºF (22.8ºC) and boiling points at or above 100ºF (37.8ºC). (c) Class IC liquids shall include those liquids that have flash points at or above 73ºF (22.8ºC), but below 100ºF (37.8ºC). (NFPA 30) Flash fire: The combustion of a flammable gas or vapor and air mixture in which the flame propagates through that mixture in a manner such that negligible or no damaging overpressure is generated. (CCPS, 1994) Flash point: The temperature at which the vapor-air mixture above a liquid is capable of sustaining combustion after ignition from an external energy source. (CCPS, 1996, no. 22) Frequency: The number of occurrences of an event per unit of time. (CCPS, 1999) Fuel gas: Gaseous fuels consisting of natural gas and various manufactured or by-product gases. Geotechnical: Relating to the engineering field which combines geology and engineering. (Merriam Webster’s Collegiate online dictionary) Grassroots: Totally new facility that may be built upon a greenfield or brownfield site. Greenfield: Undeveloped property that is being considered as a site for construction. (Dictionary.com) Hazard: A chemical or physical condition that has the potential for causing damage to people, property, or the environment. (CCPS, 1999) Hazard evaluation: The analysis of hazardous situations associated with a process or activity, using techniques to identify weaknesses in design and operation. (CCPS, 1993, no. 15) Hazardous material: In a broad sense, any substance or mixture of substances having properties capable of producing adverse effects on

Glossary

187

people, property, or the environment. Such materials may be flammable, combustible, toxic, reactive, unstable or corrosive. (CCPS, 1988) Hazardous waste: A solid waste, or combination of solid waste, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may (a) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed. (RCRA ) Incident: An unplanned event with the potential for undesirable consequences. (CCPS, 1993, no. 15) Inert: A chemical that does not react chemically with other substances. (Cambridge online) Infrastructure: The basic facilities, services, and installations needed for the functioning of a site such as transportation and communications systems, water and power lines, and public institutions including emergency response organizations. (Dictionary.com) Inherently safer: A condition in which the hazards associated with the materials and operations used in the process have been reduced or eliminated, and this reduction or elimination is permanent and inseparable. (CCPS, 1996, no. 23) Jet fire: A fire type resulting from the discharge of liquid, vapor, or gas into free space from an orifice, the momentum of which induces the surrounding atmosphere to mix with the discharged material. (CCPS, 1999 and CCPS, 1994) Knockout pot: a vessel used to separate liquids from vapors. Layout: The relative location of equipment or buildings within a given site. (CCPS, 1996, no. 22) Likelihood: A measure of the expected probability or frequency of occurrence of an event. This may be expressed as a frequency, a probability of occurrence during some time interval or a conditional probability. (CCPS, 2000) Low pressure tank: A storage tank designed to withstand an internal pressure above 0.5 psig but not more than 15 psig measured at the top of the tank. LFG (Liquefied Flammable Gas): Any flammable gaseous material or mixture of materials that is in liquid form under pressure. LNG (Liquefied Natural Gas): A fluid in the liquid state composed predominantly of methane and that can contain minor quantities of ethane, pro-

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pane, nitrogen, or other components normally found in natural gas. (NFPA 59A) LPG (Liquefied Petroleum Gas): Any material having a vapor pressure not exceeding that allowed for commercial propane composed predominantly of the following hydrocarbons, either by themselves or as mixtures: propane, propylene, butane (normal butane or isobutane), and butylenes. (NFPA 58) Mitigation: An act that causes a consequence to be less hazardous (CCPS, 2001) Mitigation factors: Systems or procedures, such as water sprays, foam systems, and sheltering and evacuation, which tend to reduce the magnitude of potential effects due to a release. (CCPS, 1999) On-stream factor: The fraction of the time that a process unit is operating Off-site exposure: People, property, or the environment located outside of the site property line that may be impacted by an on-site incident. OSBL: Outside of battery limits Piperack, pipeway, pipeband: a structure that supports pipes, power leads, and instrument cable trays. Pool fire: The combustion of material evaporating from a layer of liquid at the base of a fire. (CCPS, 1993, no. 25) Predominant wind direction: The compass direction from which the wind blows the majority of the time. Probability: The expression for the likelihood of occurrence of an event or an event sequence during an interval of time, or the likelihood of the success or failure of an event on test or on demand. By definition, probability must be expressed as a number ranging from 0 to 1. (CCPS, 2000) Property boundary: The boundary that is or can be built upon including the opposite side of a public way. (NFPA 30) Radiant heat: the heat transferred from one body to another not in contact with it but by means of wave motion through space. Refrigerated liquid: A gas that is maintained as liquid at temperatures at or below ambient temperature to reduce the storage pressure. This includes fully refrigerated LP-Gas for pressures near atmospheric pressure but not exceeding 15 psi (103 kPa) and semi refrigerated LP-Gas for pressures above 15 psi (103 kPa). (NFPA 58) Risk: A measure of human injury, environmental damage, or economic loss in terms of the incident likelihood and the magnitude of the loss or injury. (CCPS, 2000)

Glossary

189

Risk analysis: The development of a quantitative estimate of risk based on engineering evaluation and mathematical techniques for combining estimates of incident consequences and frequencies. (CCPS, 2000) Risk assessment: The process by which the results of a risk analysis are used to make decisions either through a relative ranking of risk reduction strategies or through comparison with risk targets. (CCPS, 2000) Risk management: The systematic application of management policies, procedures, and practices to the tasks of analyzing, assessing, and controlling risk in order to protect employees, the general public, and the environment as well as company assets while avoiding business interruptions. (CCPS, 2000) Roll over: The spontaneous and sudden movement of a large mass of liquid from the bottom to the top surface of a refrigerated storage reservoir due to the instability caused by an adverse density gradient. Rollover can cause a sudden pressure increase and can affect vessel integrity. (API 2510) Safe haven: A building or enclosure that is designed to provide protection to its occupants from exposure to outside hazards Satellite Instrument House (SIH): A structure containing instrument and process control equipment for one or more process units. Self-igniting: The ignition and sustained combustion of a substance without introduction of any ignition source besides thermal energy or heat of reaction resulting when combined with other substances in the surrounding environment. Self-igniting materials include materials above their autoignition temperature, chemicals that ignite due to heat of reaction with oxygen in air, and chemicals that are unstable and spontaneously combust when released. Siting: The process of locating a complex, site, plant, or unit. Turnaround: A time during which a unit is shut down for repair and maintenance after a normal run, before it is returned to operation. (Harcourt.com) Vapor cloud explosion (VCE): The explosion resulting from the ignition of a cloud of flammable vapor, gas, or mist in which flame speeds accelerate to sufficiently high velocities to produce significant overpressure. (CCPS, 1994)

Index

A Access, process units, site/plant layout, 83 Air compressors, site/plant layout, 77 Air cooled heat exchangers, equipment layout and spacing, 110 Air intake equipment, equipment layout and spacing, 107–108 Airports, 164 Air quality site selection, 30–31 site selection data requirements, 170–171 site survey, 50 B Bhopal, India disaster, 7 BLEVE potential, case history, 127–129 Block layout methods, site/plant layout, 71–72 Blowdown drums, site/plant layout, 91 Boundaries, site/plant layout, 69–70 Bulk storage, compressed and liquefied gas storage, site/plant layout, 91–92 C Carbon dioxide, site/plant layout, 80 Case histories, 127–138 BLEVE potential, 127–129 expansion issues, 134–136 fire hazards, 136–137 management of change, 137 measurement units, 138 reactive chemicals siting, 131–133 runaway reaction potential, 130–131 Catch tanks, equipment layout and spacing, 110 Chemical storage, site/plant layout, outside battery limits (OSBL), 90–91

Coal piles, outside battery limits (OSBL), site/plant layout, 92 Codes site selection data requirements, 177–178 survey and data collection guidelines, 26–28 Cogeneration facilities, equipment layout and spacing, 113 Communication systems site selection data requirements, 168 site survey, 48–49 Complex, defined, 4 Compressed gas storage, outside battery limits (OSBL), site/plant layout, 91–92 Compressors, equipment layout and spacing, 111 Construction phase support facilities, 55 transportation requirements, 44 Control facilities. See Electrical and control facilities Cooling towers, site/plant layout, 77–78 Critical structures, site/plant layout, 94–97 D Data collection guidelines. See Maps and surveys; Site selection data requirements; Site survey; Survey and data collection guidelines Distance. See Separation distance Drainage, site/plant layout, 68 E Earthquake, seismic data, site survey information requirements, 39 Electrical and control facilities site/plant layout, 80–82

191

192 Electrical and control facilities (cont.) site selection data requirements, 164–166 site survey, 47–48 Electrical switch racks, equipment layout and spacing, 116 Emergency access, process units, site/plant layout, 83 Emergency response capabilities site/plant layout, 70–71, 85 site survey, 51–53 Emergency shutdown valves, equipment layout and spacing, 114 Enclosed process units, equipment layout and spacing, 105 Environmental controls site selection, 28–32 air quality, 30–31 flood levels, 32 generally, 28–30 luminosity levels, 32 noise, 32 solid waste disposal, 31–32 wastewater, 31 site selection data requirements, 166–172 air quality, 170–171 noise and luminosity levels, 174 sanitary sewage collection/treatment, 173 wastewater, 168–172 site survey, 49–51 air quality, 50 noise and luminosity levels, 51 sanitary sewage collection/treatment, 51 wastewater, 49–50 Equipment layout and spacing, 101–119 air intake equipment, 107–108 enclosed process units, 105 equipment-to-equipment, 108–116 cogeneration facilities, 113 emergency shutdown valves, 114 fired heaters, 110 fire hydrants and monitors, 114–115 fire pumps, 114 gas compressors and expanders, 111 heat exchangers, 110 inert materials handling, 108–109 pipeways, 115 process unit spacing, 108 pumps, 111–113

Guidelines for Facility Siting and Layout reactors, 109 scrubbers and catch tanks, 110 tanks inside battery limits, 115–116 unit flares, 111 unit isolation valves, 113 unit substations and electrical switch racks, 116 vents and relief vents, 114 vessels, 109 water spray actuation valves, 114 example, 116–119 general guidelines, 103–104 optimization of, 121–125 relative location, 106–107 single- and multilevel structures, 104–105 spacing tables, 101–103 vapor cloud explosions, 105–106 Expanders, equipment layout and spacing, 111 Expansion issues, case history, 134–136 Expertise, site selection team, 15–17 Explosion scenarios, hazard screening, 23–25 F Fired heaters, equipment layout and spacing, 110 Fire hydrants, equipment layout and spacing, 114–115 Fire monitors, equipment layout and spacing, 114–115 Fire pumps, equipment layout and spacing, 114 Fire safety case history, 136–137 hazard screening, 22–23 site selection data requirements, 174 site survey, 51–53 Fire training areas, site/plant layout, 91 Firewater ponds, outside battery limits (OSBL), site/plant layout, 92 Flares site/plant layout, 78–79 unit flares, equipment layout and spacing, 111 Flooding environmental control issues, 32 site survey information requirements, 36 Fuel supply site/plant layout, 77

Index site selection data requirements, 166 site survey, 46–47 G Gas compressors and expanders, equipment layout and spacing, 111 Gases, site/plant layout, 80 Geological data site selection data requirements, 155–157 site survey information requirements, 37–39 Geotechnical studies, site/plant layout, 66. See also Soil properties Grading, site/plant layout, 68 Groundwater site/plant layout, 68 site survey information requirements, 36 H Hazard screening, 18–25 explosion scenarios, 23–25 fire scenarios, 22–23 overview, 18–20 preliminary plot area refinement, 25 toxic release scenarios, 20–22 Heaters, fired, equipment layout and spacing, 110 Heat exchangers, equipment layout and spacing, 110 Helicopter transport, 162 Housing site selection data requirements, 175 site survey, 54 Hydrocarbons, site/plant layout, 80 I Inert gases, site/plant layout, 80 Inert materials handling, equipment layout and spacing, 108–109 Infrastructure. See Utilities Inherently safer design layers of safety, 4–6 siting and layout, 9 Inside battery limits, tanks, equipment layout and spacing, 115–116 Instrument air compressors, site/plant layout, 77 Internet system, site survey, 49

193 L Landfills, outside battery limits (OSBL), site/plant layout, 92 Layers of safety, siting and layout, 4–6 Layout, optimization of, 121–125. See also Equipment layout and spacing; Site/plant layout Light levels. See Luminosity levels Liquefied gas storage, outside battery limits (OSBL), site/plant layout, 91–92 Local guidelines, survey and data collection guidelines, 26–28 Location. See Equipment layout and spacing LPG storage, BLEVE potential, case history, 127–129 Luminosity levels site selection, 32 site selection data requirements, 174 site survey, 51 M Mail system, site survey, 49 Maintenance access, process units, site/plant layout, 83 Management of change, case history, 137 Maps and surveys site selection data requirements, 152–154 site survey information requirements, 33–34 survey and data collection guidelines, 28 Marine facilities piers and wharves, site/plant layout, 89–90 site selection data requirements, 158–160 site survey, transportation, 44 Material handling, site selection data requirements, 155–156 Measurement units case history, 138 site selection data requirements, 177 Medical response capabilities, site survey, 51–53 Meteorological data site/plant layout, 68–69 site selection data requirements, 155–157 site survey information requirements, 37–39 Metering stations, pipeline, site/plant layout, outside battery limits (OSBL), 86 Microwave communications, site survey, 49 Minimization, site/plant layout, 64–65

194 Moderation, site/plant layout, 64 Multilevel structures, equipment layout and spacing, 104–105 Multi-unit blowdown drums, site/plant layout, 91 N National Oceanographic and Atmospheric Administration (NOAA), 37 Neighbors, site/plant layout, 69–70 Nitrogen, site/plant layout, 80 Noise control site selection, 32 site selection data requirements, 174 site survey, 51 O Occupied structures runaway reaction potential, case history, 130–131 site/plant layout, 94–97 On-site shipping facilities, process units, site/plant layout, 84 Optimization, of layout, 121–125 Outdoor electrical switch racks, site/plant layout, 81 Outside battery limits (OSBL), 85–92 buildings for, location of, 97 compressed and liquefied gas storage, 91–92 emergency response facilities, 85 fire training areas, 91 miscellaneous, 92 multi-unit blowdown drums, 91 piers and wharves, 89–90 pipeline metering stations, 86 pipeways, 87 site support facilities, 85 toxic and reactive chemical storage, 90–91 transfer pumps, 86–87 transportation, 85–86 truck and rail loading and unloading racks, 88–89 underground piping, 87–88 wastewater separators, 90 Oxygen, site/plant layout, 80 P Personnel site selection data requirements, 173–175 site survey, 53–54

Guidelines for Facility Siting and Layout Piers, outside battery limits (OSBL), site/plant layout, 89–90 Pigging stations, site/plant layout, outside battery limits (OSBL), 86 Pipeline metering stations, site/plant layout, outside battery limits (OSBL), 86 Pipelines site selection data requirements, 160 transportation, site survey, 42 Pipeways equipment layout and spacing, 115 site/plant layout, outside battery limits (OSBL), 87 Plant, defined, 3 Police capabilities, site survey, 51–53 Portable containers, compressed and liquefied gas storage, site/plant layout, 91–92 Ports site selection data requirements, 162–164 site survey, 44 Process control buildings, site/plant layout, 95–96 Process units equipment layout and spacing, 105, 108 site/plant layout, 82–84, 83–84 Product handling, site selection data requirements, 157–158 Project description, site selection process, 12–15, 17 Pumps equipment layout and spacing, 111–113 fire pumps, equipment layout and spacing, 114 transfer pumps, site/plant layout, outside battery limits (OSBL), 86–87 R Radio communications, site survey, 49 Railroad loading and unloading racks, site/plant layout, 88–89 site selection data requirements, 159–160 transportation, site survey, 42–43 Reactive chemicals siting, case history, 131–133 storage, site/plant layout, 90–91 Reactors, equipment layout and spacing, 109 Receiving facilities, process units, site/plant layout, 84

Index Relative location, equipment layout and spacing, 106–107 Relief vents, equipment layout and spacing, 114 Resource Conservation and Recovery Act (RCRA), 31 Risk assessment, transportation, site survey, 39–40 Risk management, siting and layout, 8 Road systems, transportation, site survey, 40–42 Runaway reaction potential, case history, 130–131 S Safety site selection data requirements, 174 site survey, 51–53 Sanitary sewage collection/treatment environmental controls, site survey, 51 site selection data requirements, 171 Satellite instrument house (SIH), site/plant layout, 81–82 Screening. See Hazard screening Scrubbers, equipment layout and spacing, 110 Security site selection data requirements, 172 site survey, 51–53 Seismic data, site survey information requirements, 39 Separation distance. See also Equipment layout and spacing equipment layout and spacing, 101–103 site/plant layout, 63–66 spacing tables, 72–74, 75 Sewage. See Sanitary sewage collection/treatment Shelters, site/plant layout, 97 Shipping facilities, process units, site/plant layout, 84 Ships piers and wharves, site/plant layout, 89–90 site selection data requirements, 160–162 site survey, transportation, 44 Simplification, site/plant layout, 64 Single level structures, equipment layout and spacing, 104–105 Site, defined, 3–4 Site/plant layout, 63–100

195 block layout methods, 71–72 electrical and control facilities, 80–82 example, 97–100 general guidelines, 64–66 occupied and critical structures, 94–97 optimization of, 121–125 outside battery limits (OSBL), 85–92 compressed and liquefied gas storage, 91–92 emergency response facilities, 85 fire training areas, 91 miscellaneous, 92 multi-unit blowdown drums, 91 piers and wharves, 89–90 pipeline metering stations, 86 pipeways, 87 site support facilities, 85 toxic and reactive chemical storage, 90–91 transfer pumps, 86–87 transportation, 85–86 truck and rail loading and unloading racks, 88–89 underground piping, 87–88 wastewater separators, 90 overview, 63–64 process units, 82–84 site factors, 66–71 emergency response support, 70–71 geotechnical studies, 66 groundwater, grading, and drainage, 68 neighbors, 69–70 topography, 66–68 weather, 68–69 spacing tables, 72–74, 75 tank storage, 92–94 utilities, 74, 76–80 cooling towers, 77–78 flares, 78–79 fuel gas and liquids, 77 gases, 80 instrument air compressors, 77 steam supply, 76–77 wastewater facilities, 76 water supply, 76 Site selection data requirements, 151–178 codes and standards, 177–178 communication systems, 166 electrical systems, 164–166 environmental controls, 166–172

196 Site selection data requirement (cont.) air quality, 170–171 noise and luminosity levels, 172 sanitary sewage collection/treatment, 171 wastewater, 166–170 fire and safety, 172 maps and surveys, 152–154 measurement systems, 179 meteorological and geological data, 155–157 security, 172 site features, 173–176 housing, 175 personnel, 173–175 support facilities, 175–176 topography, terrain and soil properties, 154–155 transportation, 157–162 marine facilities, 160–162 pipelines, 158 product and material handling, 157–158 railroads, 159–160 special requirements, 162 trucks, 158 utilities, 163–164 Site selection process, 11–32 environmental control issues, 28–32 air quality, 30–31 flood levels, 32 generally, 28–30 luminosity levels, 32 noise, 32 solid waste disposal, 31–32 wastewater, 31 example in, 55–61 hazard screening explosion scenarios, 23–25 fire scenarios, 22–23 overview, 18–20 preliminary plot area refinement, 25 toxic release scenarios, 20–22 overview, 11–12 project description, 12–15 size determination, 17–18 survey and data collection guidelines, 25–28 codes, standards, and local requirements, 26–28 maps and surveys, 28 team assembly, 15–17

Guidelines for Facility Siting and Layout Site support facilities. See Support facilities Site survey, 33–61 communications systems, 48–49 electrical systems, 47–48 environmental controls, 49–51 air quality, 50 noise and luminosity levels, 51 sanitary sewage collection/treatment, 51 wastewater, 49–50 example in, 55–61 fire, safety, and security, 51–53 information requirements, 33–39 maps and surveys, 33–34 meteorological and geological data, 37–39 topography, terrain, and soil properties, 35–37 site features, 53–55 housing, 54 personnel, 53–54 support facilities, 54–55 transportation, 39–44 marine facilities, 44 pipelines, 42 railroad, 42–43 risk assessment, 39–40 special requirements, 44 trucks, 40–42 utilities, 44–47 fuel supply, 46–47 steam supply, 46 water supply, 45 Siting and layout basis for, 8–10 changing standards for, 10 definitions, 3–4 facility types, 1 guidelines, 2 implications of, 7 importance of, 1 layers of safety, 4–6 risk management, 8 Size determination, site selection process, 17–18 Soil properties geotechnical studies, site/plant layout, 66 site selection data requirements, 154–155 site survey information requirements, 35–37

Index Solid waste disposal site selection, 31–32 site survey, 51 Spacing tables equipment layout and spacing, 101–103 examples of, 139–151 site/plant layout, 72–74, 75 Standards site selection data requirements, 179–180 survey and data collection guidelines, 26–28 Steam supply site/plant layout, 76–77 site selection data requirements, 163–164 site survey, 46 Storage compressed and liquefied gas, site/plant layout, 91–92 tank storage, site/plant layout, 92–94 toxic and reactive chemicals, site/plant layout, 90–91 Substitution, site/plant layout, 64 Support facilities site/plant layout, 70–71, 85 site selection data requirements, 177–178 site survey, 54–55 Survey and data collection guidelines, 25–28. See also Maps and surveys; Site selection data requirements; Site survey codes, standards, and local requirements, 26–28 maps and surveys, 28 Switch racks, equipment layout and spacing, 116 T Tanks inside battery limits, equipment layout and spacing, 115–116 site/plant layout, 92–94 Team assembly, site selection process, 15–17 Telephone systems, site survey, 48–49 Temporary trailers, outside battery limits (OSBL), site/plant layout, 92 Terrain and topography site/plant layout, 66–68 site selection data requirements, 154–155

197 site survey information requirements, 35–37 Toxic release scenarios, hazard screening, 20–22 Toxic storage, site/plant layout, outside battery limits (OSBL), 90–91 Traffic, transportation, site survey, 40–42 Trailers, outside battery limits (OSBL), site/plant layout, 92 Trains loading and unloading racks, site/plant layout, 88–89 site selection data requirements, 161–162 transportation, site survey, 42–43 Transfer pumps, site/plant layout, outside battery limits (OSBL), 86–87 Transportation site/plant layout, outside battery limits (OSBL), 85–86 site selection data requirements, 159–164 marine facilities, 162–164 pipelines, 160 product and material handling, 159–160 railroads, 161–162 special requirements, 164 trucks, 160 site survey, 39–44 marine facilities, 44 pipelines, 42 railroad, 42–43 risk assessment, 39–40 special requirements, 44 trucks, 40–42 Trucks loading and unloading racks, site/plant layout, 88–89 site selection data requirements, 160 transportation, site survey, 40–42 U Underground piping, site/plant layout, outside battery limits (OSBL), 87–88 Unit, defined, 3 Unit flares, equipment layout and spacing, 111 Unit isolation valves, equipment layout and spacing, 113 Unit spacing, process units, site/plant layout, 83–84

198 Unit substations, equipment layout and spacing, 116 US Geological Survey (USGS), 39 Utilities site/plant layout, 74, 76–80 cooling towers, 77–78 flares, 78–79 fuel gas and liquids, 77 gases, 80 instrument air compressors, 77 steam supply, 76–77 wastewater facilities, 76 water supply, 76 site selection data requirements, 165–166 site survey, 44–47 fuel supply, 46–47 steam supply, 46 water supply, 45 V Valves, equipment layout and spacing, 113–114 Vapor cloud explosions

Guidelines for Facility Siting and Layout equipment layout and spacing, 105–106 hazard screening, 23–25 Vents, equipment layout and spacing, 114 Vessels, equipment layout and spacing, 109 W Wastewater site/plant layout, 76 site selection data requirements, 168–172 site selection process, 31 site survey, 49–50 Wastewater separators, site/plant layout, outside battery limits (OSBL), 90 Water spray actuation valves, equipment layout and spacing, 114 Water supply site/plant layout, 76 site selection data requirements, 165 site survey, 45 Weather. See Meteorological data Wharves, outside battery limits (OSBL), site/plant layout, 89–90. See also Marine facilities