Management of Hazards Associated with Location of Process Plant Buildings

API RECOMMENDED PRACTICE 752 SECOND EDITION, NOVEMBER 2003

Management of Hazards Associated with Location of Process Plant Buildings

Downstream Segment

API RECOMMENDED PRACTICE 752 SECOND EDITION, NOVEMBER 2003

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Copyright © 2003 American Petroleum Institute

FOREWORD

This publication is intended to assist management in identifying issues related to location of process plant buildings which might be of potential concern, understanding associated hazards, and managing risk. Among hazards that potentially could affect occupants of pro- cess plant buildings are: fire, explosion, and toxic releases. This publication provides a meth- odology for assessing and evaluating the hazards associated with location of process plant buildings. It is not an engineering guide for the design of blast-resistant buildings.

Serious accidental releases of toxic material or explosions that impact occupied process plant buildings are not frequent events. Preventing incidents in process plants is a better safety investment than providing mitigation systems or redesigning process plant buildings. The implementation of process safety management, as described in API’s historical Recom- mended Practice 750, publications of the AIChE CCPS and OSHA 1910.119 is intended to improve industry's safety performance. Risk management involves cost-effective applica- tions of risk-reduction alternatives.

Because this publication affects many existing buildings within processing facilities, a substantial effort may be required for full implementation of the recommended practice. This could include identifying buildings of concern, conducting building evaluations, and, if appropriate, performing building upgrades or modifications. It is recognized that a substan- tial period of time may be required for complete application of the recommended practice, due to the scope and magnitude of the endeavor.

This second edition of API RP 752 Management of Hazards Associated with Location of Process Plant Buildings recognizes that available information, publications and relevant ref- erences concerning specific PSM activities constitute a growing body of knowledge. A num- ber of resource publications are specifically referenced in the body of this standard while others are listed in Appendix A.

API publications may be used by anyone desiring to do so. Every effort has been made by the Institute to assure the accuracy and reliability of the data contained in them; however, the Institute makes no representation, warranty, or guarantee in connection with this publication and hereby expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal regulation with which this publication may conflict.

Suggested revisions are invited and should be submitted to the standardization manager, American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

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CONTENTS

Page

1. GENERAL 1

   1. Purpose 1

   2. Scope 1

   3. Definitions 1

   4. Referenced Publications 2

2. MANAGEMENT OVERVIEW 2

   1. Hazards to Occupants of Process Plant Buildings 2

   2. Process Plant Building Issues of Concern 3

   3. Overview of Analysis Process 4

   4. Using This Recommended Practice 4

   5. Occupancy and Emergency Role Criteria 5

3. EXPLOSION ANALYSIS 7

   1. Stage 1—Building and Hazard Identification 7

   2. Stage 2—Building Evaluations 8

   3. Risk Management 11

4. FIRES 14

   1. Materials of Concern 14

   2. Building Occupancy 14

   3. Spacing 14

   4. Mitigation and Emergency Response 14

   5. Risk Reduction for Fire 16

5. TOXIC MATERIALS 16

   1. Toxic Material of Concern 16

   2. Building Occupancy 16

   3. Site Conditions 16

   4. Mitigation and Emergency Response 16

   5. Risk Reduction for Toxic Release 18

6. BUILDING CHECKLIST 18

7. PROCESS SAFETY MANAGEMENT DILIGENCE 18

APPENDIX A BIBLIOGRAPHY FOR ADDITIONAL READING 19

APPENDIX B EXPLOSION, FIRE, AND TOXIC RELEASE PHENOMENA, AND HAZARDS TO THE OCCUPANTS OF PROCESS

PLANT BUILDINGS 21

APPENDIX C DAMAGE CATEGORIZATION FOR BUILDINGS AND VULNERABILITY OF OCCUPANTS TO EXPLOSION OVERPRESSURE 23

APPENDIX D PROCESS PLANT BUILDING CHECKLIST 27

APPENDIX E EXAMPLES 29

Figures

1. Stages for Explosion Risk Analysis 4

2. An Analysis Process for an Explosion 6

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   Page

3. Sample Risk Matrix 12

4. An Analysis Process for a Fire 15

5. An Analysis Process for a Toxic Release 17

C-1 Sample Overpressure Versus Vulnerability 24

Tables

1. Examples of Process Safety Information Needs by Stage 7

2. Summary of Possible Explosion Effects on Buildings 9

3. Overpressure Effects on Various Building Components 10

4. Overpressure on Various Building Types 10

5. Typical Overpressure Effects on Unprotected People 11

6. Sample Risk-ranking Categories 13

C-1 Generic Frequencies of Major Explosions 25

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Management of Hazards Associated with Location of Process Plant Buildings

SECTION 1—GENERAL

1. PURPOSE

   This publication provides guidance for identifying hazards that may affect process plant buildings and for managing risks related to those hazards. An analysis process set forth in this Recommended Practice provides a structured approach that can improve worker safety by the following:

   1. Continuing to improve the understanding of identified hazards.

   2. Continuing to focus on accident prevention and addressing identified hazards.

   3. Managing risk.

   The methodology recommended in this document will help provide the user with an understanding of the relative risk of each building studied. This relative risk should be considered in long-range planning and projects that involve building changes (such as control building consolidation, office build- ing replacements, and so forth).

   
   

2. SCOPE

   1. Applicability

      This publication was developed for refineries, petrochemical and chemical operations, natural gas liquids extraction plants, and other facilities covered by the OSHA Process Management Standard, 29 CFR 1910.119. This publication does not apply to production facilities surrounded by navigable waters, such as offshore platforms or to storage tanks, wastewater tanks and similar facilities. Such facilities have unique siting issues which are addressed by other recommended practices, such as RP 14J for off-shore facilities.

      Additionally, this publication is not intended for use in designing and locating safe refuge from the effects of fires, explosions, and toxic releases.

      
      

   2. Relationship of this Recommended Practice to OSHA 29 CFR 1910.119

      OSHA 29 Code of Federal Regulations (CFR) 1910.119, “Process Safety Management of Highly Hazardous Chemi- cals (PSM),” includes requirements for addressing facility sit- ing as part of a process hazards analysis (PHA).

      This publication is intended to assist in identifying the sit- ing issues for process plant buildings, understanding the asso- ciated hazards, and managing the risk. Hence, this publication provides a framework that can be used to address facility sit- ing within the PHA requirements of OSHA 29 CFR 1910.119 as applied to buildings.

      The PHA as required by OSHA 29 CFR 1910.119 is intended to identify scenarios that could lead to serious release of toxic or flammable materials or an explosion. Those parts of this publication intended to assist in the PHA process are iden- tified on the flowcharts (see Figures 2, 4, and 5) by a dashed- line box labeled “PHA.” The remaining parts are intended to serve as management aids in resolving issues that arise when evaluating the location of process plant buildings.

      
      

3. DEFINITIONS

   For the purpose of this publication, the following defini- tions apply:

   1. aggregate risk: A measure of the total risk to all personnel within a building(s) or within a facility, depending upon the risks being evaluated, who are impacted by a com- mon event, taking into account the total time spent in the building(s) or facility.

   2. assessment: Describes a detailed qualitative or quantitative analysis to estimate the potential likelihood and consequences of site-specific events, and then to compare the results with acceptance criteria.

   3. confinement: A qualitative or quantitative measure of the enclosure or partial enclosure areas where a vapor cloud may be contained.

   4. congestion: A qualitative or quantitative measure of the physical layout, spacing, and obstructions within a facility that promote development of a vapor cloud explosion.

   5. evaluation-case event: The scenario with the most severe consequences, considering all incidents and their outcome, that is considered plausible or reasonably believable.

   6. evaluation: Describes the application of analytical tools to aid in making decisions about buildings.

   7. hazard: An inherent physical or chemical character- istic (flammability, toxicity, corrosivity, stored chemical or mechanical energy) or set of conditions that has the potential for causing harm to people, property, or the environment.

   8. individual risk: The risk to a single person inside a particular building. Maximum individual risk is the risk to the most-exposed person and assumes that the person is exposed.

   9. process plant building (also referred to in this recommended practice as a building): Any tem- porary or permanent building within a facility that could be

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