Flash Fire Risk Assessment for the Upstream Oil and Gas Industry

API RECOMMENDED PRACTICE 99 FIRST EDITION, APRIL 2014

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Foreword

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Contents

Page

1. Scope 1

   1. General 1

   2. Conditions of Applicability 1

2. Terms, Definitions, Acronyms, and Abbreviations 1

   1. Terms and Definitions 1

   2. Acronyms and Abbreviations 2

3. Flash Fire 3

   1. General 3

   2. Risk of Injury due to Flash Fire 3

   3. Class I Division 1 and Division 2 Locations; Flammable Vapor Illustrations 3

4. Hazard Evaluation 4

   1. General 4

   2. Hazard Identification 4

   3. Simultaneous Operations (SimOps) 4

   4. Loss of Containment 4

5. Risk Assessment Methods 5

   1. General 5

   2. Example Risk Assessment Technique 5

   3. Flash Fire Risk Assessment Worksheets and Coversheet 6

   4. Illustrated Risk Assessment for Oil and Gas Operations 6

6. Mitigation 6

   1. Layers of Protection 6

   2. Hierarchy of Controls 6

   3. FRC Selection Based on Risk Assessment 7

7. General FRC Guidelines 8

Annex A (informative) Examples of API 500 Illustrations. 10

Annex B (informative) Bowtie Model 14

Annex C (informative) Flash Fire Risk Assessment Coversheet 16

Annex D (informative) Flash Fire Risk Assessment Worksheet 19

Annex E (informative) Example Flash Fire Risk Assessment Coversheets and Worksheets 21

Annex F (informative) FRC Use Decision Tree 29

Bibliography 30

Figures

1. Risk of Flash Fire 3

2. Hierarchy of Controls Illustration 7

1. Hydrocarbon Pressure Vessel or Protected Fired Vessel in a Nonenclosed Adequately

   Ventilated Area 10

2. Ball or Pig Launching or Receiving Installation in a Nonenclosed Adequately Ventilated Area 11

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   Contents

3. Flammable Gas-blanketed and Produced Water-handling Equipment in a Nonenclosed

   Page

   Adequately Vented Area 11

4. Compressor or Pump in an Adequately Ventilated Nonenclosed Area 12

5. Drilling Rig Derrick Fully Enclosed (Open Top) 12

6. Drilling Rig Open Substructure and Semi-enclosed Derrick 13

1. Example FRC Bowtie Worksheet 14

2. Flash Fire Bowtie Example 15

C.1 Flash Fire Risk Assessment Coversheet 18

D.1 Flash Fire Risk Assessment Worksheet 20

1. Example Drilling Flash Fire Risk Assessment Coversheet 22

2. Example Drilling Flash Fire Risk Assessment Worksheet 23

3. Example Gas Processing/Midstream Flash Fire Risk Assessment Coversheet 24

4. Example Gas Processing/Midstream Flash Fire Risk Assessment Worksheet 25

5. Example Completions Flash Fire Risk Assessment Worksheet 26

6. Example Production Operations Flash Fire Risk Assessment Worksheet 27

7. Example Drilling Flash Fire Risk Assessment Worksheet with Special Conditions 28

F.1 FRC Use Decision Tree Flow Chart 29

Table

B.1 Flash Fire Engineering and Administrative Controls 15

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Flash Fire Risk Assessment for the Upstream Oil and Gas Industry

1. Scope

   1. General

      
      

      This recommended practice (RP) provides guidance for the upstream oil and gas industry on hazard identification and risk assessment exercises to assess and mitigate the risk of human injury caused by exposure to a flash fire.

      
      

      The scope of this document is limited to personnel exposed to the risk of hydrocarbon based flash fires in the upstream Exploration and Production sector of the oil and gas industry. In general, this group includes oil and gas production, drilling, well bore (well servicing) operations, and gas processing prior to interstate pipeline transportation.

      
      

   2. Conditions of Applicability

      
      

      This RP focuses on flash fires that result from the unexpected ignition of hydrocarbon vapors. Emergency preparedness (e.g. firefighting, hazmat response) for exposure to fire event greater than a flash fire is excluded from this RP and is addressed by NFPA and other standards organizations.

      
      

      Arc flash, as discussed in NFPA 70E and its other related standards, are outside the scope of this document.

      
      

      Maintenance, care, and limitation of various fire resistant clothing (FRC) materials are outside the scope of this document. These items are addressed by the manufacturer and clothing-related standards.

      
      

2. Terms, Definitions, Acronyms, and Abbreviations

   
   

   1. Terms and Definitions

For the purposes of this document, the following definitions apply.

2.1.1

Class I, Division 1 location

A location in which ignitable concentrations of flammable gases or vapors are expected to exist under normal operating conditions or in which faulty operation of equipment or processes might simultaneously release flammable gases or vapors and also cause failure of electrical equipment.

2.1.2

Class I, Division 2 location

A location in which flammable gases or vapors may be present but normally are confined within closed systems; are prevented from accumulating by adequate ventilation; or the location is adjacent to a Division 1 location from which ignitable concentrations might occasionally be communicated.

2.1.3

Class I location

A location in which flammable gases or vapors are, or may be, present in the air in quantities sufficient to produce explosive or ignitable mixtures.

2.1.4

fire

A rapid oxidation process, which is a chemical reaction resulting in the evolution of light and heat in varying intensities.

1