Management of Atmospheric Storage Tank Fires

API RECOMMENDED PRACTICE 2021 FOURTH EDITION, MAY 2001

REAFFIRMED, MARCH 2020

Management of Atmospheric Storage Tank Fires

Safety & Fire Protection

API RECOMMENDED PRACTICE 2021 FOURTH EDITION, MAY 2001

REAFFIRMED, MARCH 2020

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Copyright © 2001 American Petroleum Institute

FOREWORD

Although there are more than one hundred thousand petroleum storage tanks in service in all phases of petroleum operations, only a very small percentage of tanks ever experience a fire. Consequently, relatively few people have had direct experience with fighting tank fires. This guide was prepared to help provide a basic understanding of tank fire suppression. The information presented is based primarily upon experience in the petroleum industry over a number of years. It is not intended to exclude or limit the use of other approaches of compa- rable merit.

API strongly supports the principles of fire prevention as the most effective means of ensuring personnel and property protection. Many API publications such as Std. 2610 Design, Construction, Operation, Maintenance and Inspection of Terminal and Tank Facili- ties provide guidance for reducing the probability of fire. The information provided in this document emphasizes planning and preparation as additional steps to protect people and property in those infrequent situations where fires occur.

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 at the American Petroleum Institute, 1220 L Street, N.W., Washington, D.C. 20005.

iii

1. GENERAL 1

   1. Purpose 1

   2. Scope 1

2. REFERENCED PUBLICATIONS 1

3. DEFINITIONS 3

4. UNITS OF MEASUREMENT 5

5. TANK FIRE PREVENTION 5

6. PLANNING FOR TANK FIRE MANAGEMENT 6

   1. General Planning Process 6

   2. Incident Management System Planning 6

   3. Facility Survey and Hazard Assessment 7

   4. Types of Tank Fires and General Suppression Strategies 11

   5. Review Existing Fire Suppression Capability 13

   6. Review, Revise or Develop Fire Protection and Suppression Philosophy 13

   7. Tank–Specific Planning 14

   8. Fire Suppression Agents 19

7. PREPARATION FOR TANK FIRE SUPPRESSION 19

   1. General Preparation 19

   2. Preparation of Incident Management Resources 20

   3. Tank–Specific Preparation 20

   4. Logistics Preparation for Fire Suppression 21

   5. Training 26

8. IMPLEMENTING THE FIRE SUPPRESSION PROCESS 26

   1. General Process for Implementing Fire Suppression 26

   2. Notifying and Activating an Incident Response Organization 26

   3. Gathering and Assessing Incident Information 28

   4. Developing Incident–Specific Strategy and Tactics 29

   5. Resource Assembly and Utilization—Fighting the Fire 29

   6. Ongoing Situation Assessment and Adjustments 37

   7. Control or Extinguishment 37

   8. Overhaul and Remediation 37

   9. Incident Termination 38

   10. Critique 38

9. INVESTIGATION, REPORTING AND FOLLOW–UP 38

   1. Investigation 38

   2. Reporting 38

   3. Follow-up 38

v

APPENDIX A DEFINITION OF TERMS USED IN THIS STANDARD WHICH ARE IN GENERAL USE IN THE PETROLEUM INDUSTRY 39

APPENDIX B UNITS OF MEASUREMENT 41

APPENDIX C INCIDENT COMMAND SYSTEM (ICS) 43

APPENDIX D INCIDENT DOCUMENTATION DATA SHEET 47

APPENDIX E TYPES OF STORAGE TANKS 49

APPENDIX F FIRE PROTECTION CONSIDERATIONS RELATEDTO

FLOATING ROOF TYPE AND DESIGN 53

APPENDIX G SPECIAL HAZARDS ASSOCIATED WITH TANK FIRES 55

APPENDIX H FIRE SUPPRESSION AGENTS 59

APPENDIX I THE POTENTIAL DANGERS OF POURING FOAM ONTO PETROLEUM 65

APPENDIX J FOAM FRICTION LOSS AND BACK–PRESSURE 67

APPENDIX K DETERMINING FOAM CONENTRATE REQUIREMENTS

FOR FULL SURFACE FIRES 69

APPENDIX L DETERMINING FOAM CONCENTRATE REQUIREMENTS

FOR SEAL FIRES 73

APPENDIX M WATER FLOW THROUGH FIRE HOSES AND PIPES 75

APPENDIX N OBSERVATIONS, LESSONS LEARNED AND

“TRICKS OF THE TRADE” 77

APPENDIX O PPE FOR PERSONNEL FIGHTING TANK FIRES 83

Figures

1. Overview of Management of Atmospheric Storage Tank Fires 2

2. Planning for Storage Tank Fire Management 7

3a Tank–Specific Pre–Incident Contingency Planning Sheet 8

3b Tank–Specific Pre–Incident Contingency Planning Sheet 9

1. Preparation for Tank Fire Suppression 20

2. Water–Foam Solution Flow Requirement for Full Surface Fire

   gallons/minute at Varied Application Rates (in g/min/ft2) 22

3. Gallons of Foam Concentrate Needed for Each Ten Minutes of

   Foam Application at 1%, 3% and 6% Concentrations. 23

4. Permanently Attached Foam Chambers 24

5. Subsurface Foam Injection 24

6. Three Monitors with Large to Very Large Flow Capacity 25

7. High Capacity Monitor 25

8. Implementing the Fire Suppression Management Process 27

9. Foam for Seals Flowing into Foam Dam from Permanently

   Installed Foam Chamber 32

10. Elevating Platform Showing Access from Above Tank Rim 33

11. Special Portable Monitor Attached to Edge of Floating 33

    Tank Roof to Fight Rim Seal Fires 33

12. Wind Girder with Handrail Provides Safe Fire Personnel Access 34

C–1 Example Incident Command Data Sheet for Petroleum

Storage Tank Facilities 44

D–1 Example Incident Documentation Data Sheet 48

E–1 Fixed Cone Roof Tank 49

E–2 Low–Pressure Tanks without Weak Seam 49

E–3 Horizontal Tanks 50

Page

E–4 Close-up View of Bolted Tank Seams. 50

E–5a Internal (Covered) Floating Roof Tank 50

E–6a Open Top (External) Floating Roof Tank 50

E–6b Open Top (External) Floating Roof Tank Diagram 51

E–7 External Floating Roof Tank with Dome 52

E–8 Spheres Adjacent to Tanks 52

G–1 Boilover of a Cone–Roof Tank 56

M–1 Effect of Size on Flow Capability with Same Pressure Loss 75

N–1 Example of On–Site Tank Emergency Response Information Sign 80

Tables

1. Tank Content Characteristics and Potential Special Hazards 10

2. Tank Types and Fire Potential 11

3. Example of Minimum Resources for Seal Fire Suppression

   in 250 ft Diameter Hydrocarbon Tank 17

4. Example of Minimum Resources for Full Surface Fire Suppression

in 250 ft Hydrocarbon Tanks 18

B–1 English to Metric (SI) Units of Measure Relevant to Tank Fire Suppression 41

K–1 NFPA Full Surface Fire Minimum Application Rate Based on Fuel and

Application Method 70

K–2 NFPA Full Surface Fire Minimum Application Time in Minutes Based

on Application Method 70

K–3 Supplemental Hose Streams Recommended by NFPA 11 70

L–1 Foam Application and Time for Seal Fire Suppression

Consistent with NFPA 11 Recommendations 73

N–1 Reported Angle for Monitor to Achieve Maximum Height or Distance 77

Management of Atmospheric Storage Tank Fires

1. General

   1. PURPOSE

      This recommended practice provides experience-based information to enhance the understanding of fires in atmo- spheric storage tanks containing flammable and combustible materials. It presents a systematic management approach which can assist tank fire prevention. If fires do occur, this information can help responders optimize fire suppression techniques to reduce the severity of an incident and reduce the potential for escalation.

      
      

      1.1.1 Retroactivity

      Any provisions in this recommended practice related to design are intended for reference use when designing new facilities or when considering major revisions or expansions. It is not intended that the recommendations in this publication be applied retroactively to existing facilities. This publication should provide useful guidance when there is a need or desire to review programs or facilities.

      
      

   2. SCOPE

      This recommended practice provides information to assist management and fire suppression personnel to manage the needs associated with safely fighting fires in above ground atmospheric storage tanks. The discussion includes planning, preparation, suppression, investigation and follow-up activi- ties as shown in Figure 1.

      If a liquid at a petroleum facility can burn and is stored in an unheated tank at atmospheric pressure, it fits the scope of this publication. Fires can be fueled by flammable or combus- tible liquids ranging from gasoline to lube oil, asphalt or crude oil. Some chemicals used in the petroleum industry fit this scope. Heated tanks are not addressed in this publication, but are the subject of API 2023.

      This publication is based on industry experience. It emphasizes planning and preparation along with practical tank fire suppression strategy and tactical guidelines. Guid- ance and precautions address developing and implementing fire suppression plans for fighting fires in and around flamma- ble and combustible liquid atmospheric storage tanks. A review of fire suppression agents is provided; emphasis is on firefighting foam, with dry chemical agents discussed for seal fires and vents. It should be understood that this document provides basic guidelines. Its application must remain flexible to relate to changing technology, philosophy and regulations. Appendix N provides “Lessons Learned” information orga- nized in the same general categories shown in Figure 1.

      This publication specifically excludes fighting fires in tanks containing pressurized gases (see API Publs 2510 and

      1

      
      

      2510A) and nonmetallic tanks. Detailed discussion of types of fire protection equipment and maintenance are also outside the scope of this publication. They are covered in publications such as API Publ 2001, NFPA 11, NFPA 30 and the NFPA Fire Protection Handbook; further references are noted in Section 2.

      There may be situations in which it may not be possible, or appropriate, to mount an aggressive attack to extinguish a fire (as noted in 6.6). In most cases, if sufficient resources are available, extinguishing tank fires is conceptually simple. When enough of an appropriate extinguishing agent (fire- fighting foam) is properly applied to the burning fuel surface, the fire goes out. If the foam blanket is maintained until the fuel and tank metal are sufficiently cooled, the fire stays out. Accomplishing these conceptual goals involves both art and science—and provides a significant logistical challenge in addition to the fire suppression challenge. This publication provides guidance to assist understanding and systematically addressing these challenges.

      While this publication provides guidance for fighting tank fires, in considering tank fire issues it is prudent to review prevention of such fires. Preventing tank fires is preferable to fighting them. Section 5 and Appendix I provide brief discus- sions of fire prevention issues. Appendix O briefly reviews personal protective equipment for firefighters in the tank fire environment.

      
      

2. Referenced Publications

The most recent editions of each of the following stan- dards, codes, and publications are referenced in this publica- tion as useful sources of information. Additional information also may be available from the cited Internet World Wide Web sites.

API

Spec 12B Bolted Tanks for Storage of Production Liquids

Publ 327 Aboveground Storage Tank Standards: A Tutorial

Publ 340 Liquid Release Prevention and Detection Measures for Aboveground Storage Facilities

API 570 Piping Inspection Code: Inspection, Repair, Alteration, and Rerating of In-Ser- vice Piping Systems

RP 574 Inspection Practices for Piping System Components

RP 575 Inspection of Atmospheric and Low-Pres- sure Storage Tanks

RP 576 Inspection of Pressure Relieving Devices