mp70p01

Version 0

Loss Prevention - Facilities MP 70-P-01

August 1998

Scope

This ExxonMobil Engineering Master Practice (EMEP) defines the design basis for fire protection and loss prevention measures in refining, chemical, marketing, exploration and producing facilities.

MP 70-P-01 Loss Prevention - Facilities August 1998

© Mobil Oil, 1997 2 of 80

Table of Contents

Scope.................................................................................................................................................. 1

Table of Figures ............................................................................................................................... 7

1. References ................................................................................................................................. 8

1.1. Master Practices–ExxonMobil Engineering Master Practices ................................. 8

1.2. ExxonMobil Tutorials ...................................................................................................... 9

1.3. ANSI–American National Standards Institute ............................................................ 9

1.4. ANSI/ISA–American National Standards Institute/Instrument Society of America........................................................................................................................................... 9

1.5. API–American Petroleum Institute ............................................................................... 9

1.6. ASTM–American Society for Testing and Materials ...............................................10

1.7. BOCA–Building Officials and Code Authorities International ................................10

1.8. IEC–International Electrotechnical Commission .....................................................10

1.9. NFPA–National Fire Protection Association.............................................................10

1.10. UL–Underwriters Laboratories Inc.............................................................................12

2. General Design........................................................................................................................12

2.1. Regulatory Requirements ...........................................................................................12

2.2. Design Objective ...........................................................................................................13

2.3. Hazard Assessment .....................................................................................................13

2.4. Supplemental Loss Prevention...................................................................................13

2.5. Manpower Levels..........................................................................................................13

2.6. LPG Facilities................................................................................................................13

2.7. Acceptance Tests .........................................................................................................13

3. Fundamental Loss Prevention............................................................................................14



3.1. Aviation, Marine and Diving ........................................................................................14

3.2. Cranes ............................................................................................................................15

3.3. Layout and Spacing .....................................................................................................18

3.4. Personnel Protection....................................................................................................18

3.5. PPE Storage and Maintenance..................................................................................19

3.6. Access/Egress ..............................................................................................................19

3.7. Electrical, Static Electricity and Emergency Power.................................................20

3.8. Drainage and Sewer Systems ....................................................................................26

3.9. Ventilation and Pressurization....................................................................................30

3.10. Signs ...............................................................................................................................32

4. Fireproofing .............................................................................................................................33

5. Firewater Systems..................................................................................................................33

5.1. Provision ........................................................................................................................33

5.2. Fire Hydrants .................................................................................................................35

5.3. Firewater Monitors ........................................................................................................36

5.4. Portable Firewater and Foam/Water Monitors.........................................................38

5.5. Live Hose Reels ............................................................................................................39

5.6. Automatic Sprinkler Systems......................................................................................40

5.7. Firewater Spray Systems ............................................................................................41

5.8. Foam and Foam/Water Spray Systems....................................................................44

5.9. Hose Carts and Houses ..............................................................................................44

6. Special Systems–Clean Agent, CO2, Twin Agent, AFFF and Dry Chemical Systems 45

6.1. General...........................................................................................................................45

6.2. Gas Turbines–CO2 .......................................................................................................45

6.3. Computer Rooms–CO2 ................................................................................................46



6.4. Carbon Dioxide Systems .............................................................................................47

6.5. Pier and Wharf–Twin Agent Dry Chemical/Aqueous Film Forming Foam Unit..47

6.6. Twin-Agent Hose Reels ...............................................................................................48

6.7. Kitchen and Galley Grease Hoods–Fixed Dry Chemical .......................................48

7. Hand-Portable and Wheeled Fire Extinguishers............................................................49

7.1. Basis...............................................................................................................................49

7.2. CO2 .................................................................................................................................49

8. Detection and Alarm Systems ............................................................................................49

9. Process Safety ........................................................................................................................49

9.1. Battery Limit Valves......................................................................................................49

9.2. Safety Instrumented Systems.....................................................................................50

9.3. Heater, Fired Reboiler and Combustion Safety Controls .......................................50

9.4. Pressure Vessel Fire Protection.................................................................................53

9.5. Emergency Shutdown..................................................................................................53

9.6. Relief and Depressuring ..............................................................................................58

10. Pipelines and Pigging Facilities .........................................................................................59

10.1. General...........................................................................................................................59

10.2. Level of Protection–ESDVs and Related Equipment..............................................60

11. Flame Arrestors ......................................................................................................................60

12. Explosion Prevention............................................................................................................60

12.1. Purging and Inerting Systems ....................................................................................60

12.2. Explosion Suppression Systems................................................................................60

13. Power Plants............................................................................................................................61

13.1. General...........................................................................................................................61

14. Buildings...................................................................................................................................61



14.1. Building Construction ...................................................................................................61

14.2. Building Areas ...............................................................................................................61

14.3. Fire Separations............................................................................................................62

14.4. Life Safety......................................................................................................................62

14.5. Interior Hazard Segregation........................................................................................63

14.6. Central Control Facilities .............................................................................................63

14.7. Exposure Protection.....................................................................................................63

15. Warehousing............................................................................................................................64

15.1. General...........................................................................................................................64

16. Plastic Warehousing & Storage Areas .............................................................................65

16.1. General...........................................................................................................................65

16.2. Storage of Expanded Group A Plastics Bulk Rolls .................................................65

16.3. Warehouse Storage of Plastic Products in Racks...................................................66

16.4. Pentane System Areas................................................................................................67

16.5. Rubber Tire Storage Areas .........................................................................................68

16.6. Storage Containers ......................................................................................................69

16.7. Drainage.........................................................................................................................69

16.8. Smoke and Heat Venting ............................................................................................70

17. Computer Rooms...................................................................................................................71

17.1. General...........................................................................................................................71

17.2. Exposure Protection.....................................................................................................71

17.3. Construction ..................................................................................................................71

17.4. General Computer Area Requirements ....................................................................73

17.5. Machines and Cables ..................................................................................................73

17.6. Fire Protection Systems ..............................................................................................73



17.7. Utilities ............................................................................................................................74

18. Piers and Wharves.................................................................................................................75

18.1. Pier and Wharf Construction.......................................................................................75

18.2. Fire Stops and Spill Containment ..............................................................................75

18.3. Fire Protection ...............................................................................................................76

18.4. Fire Boats.......................................................................................................................77

18.5. Alarms and Communications ......................................................................................78

19. Truck Loading Rack Protection..........................................................................................78

19.1. Design Basis..................................................................................................................78

19.2. Fire Extinguishers.........................................................................................................78

19.3. Shutdown Systems.......................................................................................................79

19.4. Fixed Fire Protection Systems ...................................................................................79



Table of Figures

Figure 1: Unloading Cargo with Area Adequately Ventilated ........................................... 21

Figure 2: Handling Class I Products with a Nearby Open Oil Drainage Sump ............ 22

Figure 3: Loading Crude or Class I Products at High Pumping Rates........................... 23

Figure 4: Firewater System Decision Tree............................................................................. 34

Figure 5: Firewater System Decision Tree (Continued) ..................................................... 35



1. References

The following publications form a part of this Master Practice. Unless otherwise specified herein, use the latest edition.

1.1. Master Practices–ExxonMobil Engineering Master Practices

MP 01-P-10 Blast-Resistant Buildings

MP 01-P-13 Warehouse Buildings

MP 01-P-18 Plant Drainage & Sewer Systems

MP 15-P-04 Centrifugal Compressors

MP 15-P-05 Reciprocating Compressors

MP 16-P-31A Piping-Classifications-(E&P, On/Offshore)

MP 32-P-06 Process Analyzers

MP 32-P-07 Safety Interlock Systems and Alarms

MP 32-P-09 Heater Controls

MP 32-P-12 Instrumentation for Watertube Steam Boilers

MP 33-P-06 Electrical - Pressurizing Systems for Buildings

MP 33-P-25 Electrical - Lighting, Receptacles and Associated Equipment

MP 33-P-28 Electrical - Navigational Aids

MP 33-P-32 Electrical - Intrafacility Communication Systems and Alarm Systems

MP 41-P-09 Power Gen Systems-Technologies & Selection

MP 70-P-02 Fire Protection - Storage Tanks

MP 70-P-03 Hazard Assessment

MP 70-P-04 Recommended Spacing Within Operating Facilities

MP 70-P-05 Fireproofing

MP 70-P-06 Pressure Relief and Vapor Depressuring Systems

MP 70-P-07 Firewater Systems and Devices

MP 70-P-09 Fire and Gas Detection

MP 70-P-11 Portable Fire Extinguishers



1.2. ExxonMobil Tutorials

EPT 01-T-10 Marine Hose

EPT 02-T-05 Wastewater Systems

EPT 09-T-04 Piping-Construction

EPT 15-T-01 Small Bulk Plant Design

EPT 15-T-10 Tank Truck Loading Racks

EPT 15-T-18a Electrical Design for Marketing Plants

EPT 15-T-18b Electrical Design for Marketing Plants

1.3. ANSI–American National Standards Institute

ANSI A14.3 Ladders - Fixed - Safety Requirements

ANSI A1264.1 Safety Requirements for Workplace Floor and Wall Openings, Stairs, and Railing Systems

1.4. ANSI/ISA–American National Standards Institute/Instrument Society of America

ANSI/ISA S84.01-1996

Application of Safety Instrumented Systems for the Process Industries

1.5. API–American Petroleum Institute

API PUB 2510A Fire Protection Considerations for the Design and Operation of Liquefied Petroleum Gas (LPG) Storage Facilities, Second Edition, December 1996

API RP 14B Design, Installation, Repair and Operation of Subsurface Safety Valve Systems Fourth Edition; (ISO 10417) Errata - 1996

API RP 14C Recommended Practice for Analysis, Design, Installation, and Testing of Basic Surface Safety Systems for Offshore Production Platforms Fifth Edition; Errata - 1994

API RP 14E Recommended Practice for Design and Installation of Offshore Production Platform Piping Systems Fifth Edition

API RP 14F Recommended Practice for Design and Installation of Electrical Systems for Offshore Production Platforms Third Edition


© Mobil Oil, 1997 10 of 80

API RP 500 Recommended Practice for Classification of Locations for Electrical Installations at Petroleum Facilities First Edition (Supersedes RP 500A, RP 500B, RP 500C)

API RP 2003 Protection Against Ignitions Arising out of Static, Lightning, and Stray Currents Fifth Edition (Replaces PUBL 1003)

API STD 2510 Design and Construction LPG Installations Seventh Edition

1.6. ASTM–American Society for Testing and Materials

ASTM D56 Standard Test Method for Flash Point by Tag Closed Tester

ASTM D93 Standard Test Methods for Flash Point by Pensky-Martens Closed Cup Tester IP Designation: D34/88

ASTM D323 Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)

1.7. BOCA–Building Officials and Code Authorities International

BOCA National Building Code

1.8. IEC–International Electrotechnical Commission

IEC 61508-1 Ed. 1 Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems, Part 1

IEC 61508-2 Ed. 2 Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems - Part 2: Requirements for Electrical/Electronic/Programmable Electronic Safety-Related Systems

1.9. NFPA–National Fire Protection Association

NFPA 10 Portable Fire Extinguishers; Errata - 1994, Errata - 1995 (National Fire Codes, vol. 1)

NFPA 101 Code for Safety to Life from Fire in Buildings and Structures (National Fire Codes, vol. 5)

NFPA 11 Standard for Low-Expansion Foam (National Fire Codes, vol. 1)

NFPA 11A Standard for Medium- and High-Expansion Foam Systems (National Fire


© Mobil Oil, 1997 11 of 80

Codes, vol. 1)

NFPA 12 Standard on Carbon Dioxide Extinguishing Systems; Errata - 1995 (National Fire Codes, vol. 1)

NFPA 13 Installation of Sprinkler Systems (National Fire Codes, vol. 1)

NFPA 14 Standard for the Installation of Standpipe and Hose Systems (National Fire Codes, vol. 1)

NFPA 15 Standard for Water Spray Fixed Systems for Fire Protection (National Fire Codes, vol. 1)

NFPA 17 Standard for Dry Chemical Extinguishing Systems (National Fire Codes, vol. 1)

NFPA 2001 Standard on Clean Agent Fire Extinguishing Systems

NFPA 204M Guide for Smoke and Heat Venting (National Fire Codes, Vol. 9)

NFPA 220 Types of Building Construction

NFPA 231 Standard for General Storage; Errata - 1995 (National Fire Codes, vol. 6)

NFPA 231C Rack Storage; Errata - 1995 (National Fire Codes, vol. 6)

NFPA 231D Standard for Storage of Rubber Tires; Errata - 1995 (National Fire Codes, vol. 6)

NFPA 24 Standard for the Installation of Private Fire Service Mains and Their Appurtenances (National Fire Codes, vol. 1)

NFPA 252 Standard Methods of Fire Tests of Door Assemblies (National Fire Codes, vol. 6)

NFPA 255 Standard Method of Test of Surface Burning Characteristics of Building Materials (National Fire Codes, vol. 6)

NFPA 257 Standard on Fire Test for Window and Glass Block Assemblies (National Fire Codes, vol. 6)

NFPA 30 Flammable and Combustible Liquids Code (Includes Tentative Interim Amendment - 1996) (National Fire Codes, vol. 1)

NFPA 307 Standard for the Construction and Fire Protection of Marine Terminals, Piers, and Wharves (National Fire Codes, vol. 6)

NFPA 496 Standard for Purged and Pressurized Enclosures for Electrical Equipment (National Fire Codes, vol. 7)

NFPA 497A Recommended Practice for Classification of Class I Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas (National Fire Codes, vol. 11)

NFPA 58 Standard for the Storage and Handling of Liquefied Petroleum Gases Tentative Interim Amendment 1996 (National Fire Codes, vol. 2)

NFPA 654 Standard for the Prevention of Fire and Dust Explosions in the Chemical, Dye, Pharmaceutical, and Plastics Industries (National Fire Codes, vol. 7)

NFPA 68 Guide for Venting of Deflagrations (National Fire Codes, Vol. 9)


© Mobil Oil, 1997 12 of 80

NFPA 69 Explosion Prevention Systems; Tentative Interim Amendment - 1995 (National Fire Codes, vol. 2)

NFPA 70 National Electrical Code 1996 Edition Errata #1; Tentative Interim Amendment 1996

NFPA 72 National Fire Alarm Code

NFPA 77 Recommended Practice on Static Electricity (National Fire Codes, Vol. 9)

NFPA 80 Standard for Fire Doors and Fire Windows (National Fire Codes, vol. 4)

NFPA 80A Recommended Practice for Protection of Buildings from Exterior Fire Exposures (National Fire Codes, Vol. 9)

NFPA 8501 Standard for Single Burner Boiler Operation (Formerly NFPA 85A)

NFPA 8502 Standard for the Prevention of Furnace Explosions/Implosions in Multiple Burner Boilers Revision and Renumbering of ANSI/NFPA 85C-1991; Errata 03/01/1996

NFPA 86 Standard for Ovens and Furnaces (National Fire Codes, vol. 4)

NFPA 90A Standard for the Installation of Air Conditioning and Ventilating Systems (National Fire Codes, vol. 4)

NFPA 91 Standard for Exhaust Systems for Air Conveying of Materials (National Fire Codes, vol. 4)

NFPA 96 Ventilation Control and Fire Protection of Commercial Cooking Operations; Errata - 1994 (National Fire Codes, vol. 4)

1.10. UL–Underwriters Laboratories Inc.

UL 478 Standard for Safety for Data Processing Equipment/Power Supplies

2. General Design

2.1. Regulatory Requirements

The design basis for fire protection and loss prevention measures in facilities shall be in accordance with requirements of this EMEP, unless superceded by more stringent local regulations.


© Mobil Oil, 1997 13 of 80

2.2. Design Objective

Loss prevention provisions for a facility shall be established in accordance with the potential hazard to operating personnel, the facility, the public and the environment.

2.3. Hazard Assessment

A hazard assessment shall be performed for any facility in accordance with MP 70-P-03. The hazard assessment shall be used to identify potential hazards and establish means to prevent or mitigate the consequences. It shall also establish protective criteria, which may exceed those contained herein.

2.4. Supplemental Loss Prevention

Where facility loss prevention does not meet Master Practice standards, other fire protection and/or fire fighting facilities may need to be provided based on further evaluation of the risk involved.

2.5. Manpower Levels

The provisions of this Master Practice shall be based on the assumption that a minimum number of plant operators are available for fire fighting.

2.6. LPG Facilities

Areas and equipment handling or storing LPG as a product or refrigerant shall be designed, constructed and operated in accordance with API STD 2510 and NFPA 58.

2.7. Acceptance Tests

Acceptance tests shall be performed on all fire protection and safety systems or equipment.


© Mobil Oil, 1997 14 of 80

3. Fundamental Loss Prevention

||Start E&P Only

3.1. Aviation, Marine and Diving

Facilities are designed to minimize hazards and achieve safe interface between platform operations and the support services provided by aviation and marine activities.

Appropriate communications are provided for routine and emergency activities.

3.1.1. Helicopter Operations Overall platform facilities layout is evaluated to identify and to minimize conditions which might interfere with helicopter operations. These include:

1. Location of vents and flares

2. Engine exhausts (especially gas turbine)

3. Projections such as crane booms, masts and radio towers

4. Air turbulence (for example, the air foil effect)

Appropriate provisions are made for the safe and logical movement of personnel to and from a helicopter.

3.1.2. Marine Facilities Facilities provided for the interface with marine vessels are evaluated to identify and minimize conditions that negatively affect safety associated with the following:

1. Mooring bridles and bumpers for close-in activities

2. Handling of hoses for transfer of water, fuel, drilling materials, etc.

3. Compatib ility of personnel transfer facilities with the type(s) of vessels to be used

3.1.3. Diving Support Facilities

A determination is made of the need for diving support facilities on board the platform. When it is determined that there is a permanent or periodic need to place diving facilities on board, provision is made to ensure that the following conditions are met:

1. Space is available to place all modules.


© Mobil Oil, 1997 15 of 80

2. Modules will be placed in a safe area.

3. Storage is available for diving gases, compressors, etc.

4. Compressors are located for air intake from a safe location.

5. Means of platform voice communication is provided between the control room and the diving supervisor.

3.2. Cranes

Cranes are used extensively on offshore platforms. The selection and placement of cranes is one of the most important aspects of platform design. The following conditions shall be considered when cranes are installed on platforms:

1. The ability of the crane operator to see the laydown area

2. The ability of the crane operator to see the vessel

3. The lift route from the vessel to the laydown area

The crane operator shall be able to communicate with the crew rigging the equipment. This can be accomplished through PA speakers or two-way radio.

The crane operator shall have VHF radios for communication with the vessel captain.

All cranes that are used to lift personnel shall be equipped with an anti two-block device. Installation of this device on all platform cranes warrants strong consideration. On manned platforms, the ability for the crane boom to reach a helideck, in order to facilitate medical evaluation of personnel, is also of prime importance.

All cranes shall be equipped with a weight indicator for fast and load lines.

Access to boom laydown areas shall not create a hazard for employees who provide maintenance on the cables and boom.

Table 1: Fire Protection System/Location

Living Qtrs Safe Haven (Note 1)

Con-trol Rooms (Note 2)

Gener-ators in Modules

Gener-ators in Build-ings

Switch-gear

Emer-gency Gener-ator

Comms Equip-ment

HVAC Fan Room

Tur-bine Enclo-sures

Well-heads Mani-folds (Note 3)

Ventilation X X X X X

Fire SD X X X X X

Gas SD X X X X X

Pressurization X X X X


© Mobil Oil, 1997 16 of 80

Living Qtrs Safe Haven (Note 1)

Con-trol Rooms (Note 2)

Gener-ators in Modules

Gener-ators in Build-ings

Switch-gear

Emer-gency Gener-ator

Comms Equip-ment

HVAC Fan Room

Tur-bine Enclo-sures

Well-heads Mani-folds (Note 3)

Fire SD

Gas SD X X X X

Fire Detection

Smoke X X X X X X

Heat X X X X X

Flame

Discharge System

X X X X

SD Level 2 2 1

Gas Detection

Room/Area

X X X X X

Air Inlet X X X X X X X X

Fire System

Sprinkler X X

Pre-Act Sprinkler

X X X X

Water Spray

X

Special X X X

Manual

Hose Reel

X X X

Dual Agent

Monitors X


© Mobil Oil, 1997 17 of 80

Table 2: Fire Protection System/Location (Continued)

Separation and Process (Note 3)

Platform Utilities (Note 3, 4)

Compressors (Note 3)

Plat-form Drilling Rig

Shale Shaker & Mud Pit

Mud Pumps

Work-shops & Storage (Ware-house)

Lab. Heli-deck

Ventilation X X X X X X X

Fire SD X X X X X

Gas SD X X X X X X

Pressurization X X X X

Fire SD

Gas SD X X X X

Fire Detection

Smoke X X

Heat X X X X X

Flame

Discharge System

X X X

SD Level 2 2 2

Gas Detection

Room/Area X X X

Air Inlet X X X X

Fire System

Sprinkler X X

Pre-Act Sprinkler

X X X X

Water Spray

X X X X X

Special X X

Manual

Hose Reel X X X X X

Dual Agent

X

Monitors X X X X


© Mobil Oil, 1997 18 of 80

SPECIFIC NOTES:

1. Provide ventilation system shut down (manual) in living quarters to be operated when smoke is drawn in through the air inlet.

2. Control room protection is for major control centers that are normally manned. Control points on less complex platforms may not require sprinklers. Consider CO2 locally within control cabinets as an alternative in such cases.

3. Fixed fire fighting monitors may be provided in lieu of water sprays for protection of areas when assurance can be made as to adequate coverage. Water sprays may be manually operated when platform layout and size enable rapid operation following detection of fire.

4. Platform utilities that do not constitute a fire hazard and are not exposed to fire from hazardous area(s) need not be protected by water spray. Fire and gas detection and ventilation shutdown (as appropriate) are recommended.

End E&P Only||

3.3. Layout and Spacing

Adequate layout and spacing are fundamental to safety and prevention of losses. MP 70-P-04 provides guidance on minimum spacing for equipment within the unit and property boundaries as well as between the company facilities and adjacent off-site areas. MP 70-P-04 addresses both onshore and offshore facilities.

3.4. Personnel Protection

3.4.1. Personnel Protection Assessment

3.4.1.1. Basis

An assessment based on the following shall be made to determine personnel protection needs.

• Potential exposure of personnel to harmful chemical or physical agents during normal operations or maintenance activities

• The need for manual fire fighting, rescue or other emergency response activity

• Local company standards

• Local regulatory requirements


© Mobil Oil, 1997 19 of 80

3.4.1.2. Scope

A list of recommended personnel protection needs shall be provided, including quantities and types of each. Personnel protection for consideration shall include the following:

• Respiratory protection equipment

• Fire fighter protective clothing (turnout gear), including helmets, coats, pants, gloves and boots

• Exposure suits and personal flotation devices for working over water; for example, loading docks

• Emergency shower/eye wash stations

• Special apparel (e.g., hoods, aprons, gloves, etc.) for handling corrosive materials

• Miscellaneous items (e.g., goggles, face shields)

3.5. PPE Storage and Maintenance

For each item of required equipment, provision shall be made for the following:

• Placement of equipment strategically located in proximity to the hazard for which it is intended.

• Storage of equipment that is accessed infrequently.

• Service and repair of equipment that is maintained offshore or in a remote location.

• All equipment required by this Section shall be tested and certified in accordance with standards acceptable to ExxonMobil.

3.6. Access/Egress

3.6.1. Walking/Working Surfaces Walking/working surfaces shall be designed to avoid slippery conditions and tripping hazards. In addition, walkways shall be free of obstructions.

3.6.2. Equipment, Valve and Instrument Location To the extent feasible, equipment, valves and instrumentation located above grade shall be designed to be operated, tested and calibrated from grade or from deck level. Alternatively, those accessed routinely shall be provided with a stairway to an elevated platform. Those accessed infrequently may be provided with a fixed vertical ladder. Access shall be provided to equipment,


© Mobil Oil, 1997 20 of 80

such as compressors and pumps to avoid stepping on piping or other appurtenance not specifically designed for that purpose.

3.6.3. Scaffolding Scaffolding shall be limited to very infrequent access, such as turnaround activities.

3.6.4. Stair and Ladder Design Design and construction of all ladders shall conform to ANSI A14.3 and stairs shall conform to ANSI A1264.1, or other national standards approved by ExxonMobil.

3.6.5. Emergency Response Considerations Designated walkways and stairways between routinely occupied work areas shall have adequate vertical and horizontal clearance for emergency response personnel and their equipment.

3.6.6. Grade Separations Where grade separations are unavoidable, ramps shall be provided to minimize tripping hazards and to facilitate use of wheeled equipment (for example, fire extinguishers, oxygen/acetylene rigs and handcarts).

3.7. Electrical, Static Electricity and Emergency Power

3.7.1. Electrical Area Classification

3.7.1.1. Basis

Classification of areas for electrical purposes shall be as specified by API RP 500. Electrical equipment shall meet requirements of NFPA 70.

3.7.1.2. Non-Electrical Sources

Non-electrical sources of ignition, such as internal combustion engines and fired heaters, shall not be permitted in electrically classified areas.

3.7.1.3. Petroleum Piers and Wharves

Petroleum piers and wharves shall be electrically classified in accordance with NFPA 30, NFPA 70 and NFPA 497A and API RP 500. Local conditions, ordinances or codes shall not reduce classified area limits to less than those required in this Master Practice. Ordinary electrical equipment is permitted in unclassified areas provided that equipment meets the requirements of NFPA 70 for the outdoor location in which it is installed.


© Mobil Oil, 1997 21 of 80

Above-deck areas of petroleum piers or wharves are considered to be adequately ventilated and, under normal conditions, flammable vapor/air mixtures are not present. However, areas around tanker loading facilities shall be classified as Division 1 areas, where crude oil or other Class I products are loaded at high pumping rates. Open venting of large volumes of vapors which occurs at deck level or open cargo hose drainage sumps shall be classified as Division I areas.

Figure 1: Unloading Cargo with Area Adequately Ventilated


© Mobil Oil, 1997 22 of 80

Figure 2: Handling Class I Products with a Nearby Open Oil Drainage Sump


© Mobil Oil, 1997 23 of 80

Figure 3: Loading Crude or Class I Products at High Pumping Rates

3.7.2. Static Electricity and Stray Currents

3.7.2.1. Basis

Provide protection from static electricity or stray currents in accordance with API RP 2003. Static electricity control measures shall be in accordance with NFPA 77.

3.7.2.2. Piers and Wharves

For petroleum piers and wharves, protection measures shall include a deck level ground connected to a ground plate below water level where product piping is insulated from the water by a concrete or wood pier.

3.7.2.3. Insulating Flanges and Loading Arms

3.7.2.3.1. Location

Install insulating flanges in each loading arm. Loading arms shall include the insulating feature in the design of the arm, taking into consideration strength and fire resistance. Loading arms fitted with lever-operated valves, serving


© Mobil Oil, 1997 24 of 80

as pressure release or breakers, shall be fitted with a non-conductive material on the lever arm.

3.7.2.3.2. Protection of Insulating Flanges

Protect insulating flanges from environmental elements to prevent stray current short-circuiting across flanges due to conductance in dirt or rainwater.

3.7.2.3.3. Design

Install an insulating flange joint where each conductive type cargo hose connects to the pier or wharf piping. To protect insulating flanges connected to hoses from being disturbed or ineffective due to constant hose changing, a spool piece shall be fitted to the hose side of an insulating flange.

3.7.3. Emergency Power

3.7.3.1. Basis

Emergency power systems shall be installed to provide power during emergencies that result in the loss of main power generation or purchased power.

3.7.3.2. Systems Requiring Emergency Power

The following systems shall receive power from an emergency power source:

• Communications

− Radio (VHF and UHF)

− Emergency telephones

− Emergency PA system throughout the platform/plant

• Lights in muster areas, control rooms, emergency exit routes and abandonment points

• Fire suppression systems

• Evacuation systems in offshore E&P facilities

• Emergency shutdown systems

• Fire and gas detection systems

• Designated HVAC (heating, ventilation and air conditioning)

• Navigation aids

Additional systems, such as UPS, shall be provided for the emergency systems, as determined by the following criteria:


© Mobil Oil, 1997 25 of 80

• Criticality of the equipment

• Desired power availability and reliability

||Start E&P Only

3.7.3.2.1. Communications

This Section covers the loss prevention aspects of platforms communications. It does not address power requirements and equipment specifications, which are covered by MP 33-P-32.

All communications equipment shall have electrical ratings appropriate for their location, as specified in API RP 500, API RP 14F and other national standards recognized by ExxonMobil.

Communications for manned platforms shall include both internal and external means as follows:

• Internal Communications (On Platform)

− General platform alarm (GPA)

− Public address system (PA)

− Telephone (PABx)

− Radio (typically hand-held UHF/VHF)

• External Communications (Off Platform)

− UHF radio (aircraft)

− VHF radio (marine)

− Telecoms (PABx, microwave and/or satellite)

− Telemetry

• The platform lifeboat(s) shall have UHF and VHF radios to provide communication with aviation and marine traffic. Crane operators shall have VHF radios for communication with vessel captains.

• The following minimum acceptable loss prevention requirements shall apply to offshore platform communications systems:

− PA and audio alarm speakers shall be distributed platform-wide and must be audible in all areas of the platform.

− In addition to PA and alarm speakers generally distributed on the platform, alarm sets with visual alarms (lights) shall be provided in high noise areas (that is, above 90 dBA).


© Mobil Oil, 1997 26 of 80

− Audio and visual alarms shall be separate and distinct from general platform emergency and abandon-platform alarms.

− Emergency alarms shall be distinct and separate from process alarms.

− The radio operator room shall be located in the safe haven.

− Communication equipment rooms shall be located in the safe haven or other designated safe area.

− Microwave disks and antennas shall be located in areas that are not vulnerable to fire, explosion and mechanical damage.

Critical platform communications (that is, PA, alarms, radio) shall be supported by the platform UPS system or by dedicated battery backup to main power.

3.7.3.2.2. Emergency Generators

Emergency generators shall be provided with a dedicated fuel supply and shall be capable of handling the startup load of the emergency system.

End E&P Only||

3.7.3.3. Communication Cable Routing

Communications cables and junction boxes shall be routed and located away from hazardous areas or shall be fireproofed/fire resistant. Hazard assessment techniques as specified by MP 70-P-03 shall be used to identify and assess possible communications system vulnerability and common mode failure.

3.8. Drainage and Sewer Systems

3.8.1. Segregation of Sewer Systems Two sewer systems shall be provided as follows:

• An oily water sewer system with necessary fire seals

• A clean water system for storm water or firewater drainage

The capacity of the sewer systems shall be sufficient to avoid liquid backup under various types of loading, such as rainfall, firewater and process drainage (see EPT 02-T-05).

A separate drainage system shall be provided for process drains through a closed drainage system.


© Mobil Oil, 1997 27 of 80

3.8.2. Process Area Drainage

3.8.2.1. Basis

Process unit surface drainage system design shall be sized on the basis of process drainage plus rainfall, or process drainage plus design firewater capacity, whichever is greater.

||Start M&R Only

The minimum-sized catch basin shall accommodate a flow of 114 m3/h (500 US gpm).

End M&R Only||

||Start Chemical Only

The minimum-sized catch basin shall accommodate a flow of 114 m3/h (500 US gpm).

End Chemical Only||

3.8.2.2. Design

Area grading shall be provided for drainage away from vessels toward catch basins, to prevent accumulation of flammable liquid or vapor adjacent to or beneath vessels. All drains shall be designed in accordance with MP 01-P-18.

||Start M&R Only

The unit shall be graded to segregate adjacent processing areas from each other. This can be accomplished by varying the slope of the drained areas to the catch basins. Then the drainage from furnaces, pump rows, exchanger banks, tower groupings, etc. will each flow to separate catch basins, fitted with suitable fire seals to prevent fire spread to an adjacent area. The high point of grade shall be located along the center of the process unit and interconnecting pipeways so that liquids do not collect beneath the pipeways.

End M&R Only||


The unit shall be graded to segregate adjacent processing areas from each other. This can be accomplished by varying the slope of the drained areas to the catch basins. Then the drainage from furnaces, pump rows, exchanger banks, tower groupings, etc. will each flow to separate catch basins, fitted with suitable fire seals to prevent fire spread to an adjacent area. The high point of grade shall be located along the center of the process unit and interconnecting pipeways so that liquids do not collect beneath the pipeways.


© Mobil Oil, 1997 28 of 80

End Chemical Only||

3.8.2.3. Pump Rows

Drainage from pump bases and glands shall enter an equipment drain bell that shall be provided with drip-type bases to facilitate good housekeeping and drainage.

The maximum number of pump drains connected without seals to the same sewer branch shall be four.

3.8.2.4. Blowdown Drains

The process drainage system shall be provided for liquid hydrocarbon drainage, including blowdown drains from high-pressure vessels and blowdowns from level gauges.

3.8.2.5. Open Catch Basins

Open catch basins with sealed outlets shall not be located closer than 9 m (30 ft) to fired heaters or similar constant ignition sources. Dry box catch basins shall be located adjacent to fired heaters and separately drained through sealed outlets into the open catch basins.

3.8.3. Sewer Design

3.8.3.1. Basis

The sewer shall be designed in accordance with EPT 02-T-05. The minimum size for a single branch line shall be 100 mm (4 in).

3.8.3.2. Main Laterals

On main laterals between process units, f ire seals shall be provided on cleanouts to prevent flame fronts from moving through partially filled sewer lines.

3.8.3.3. Curbing

Low curbing may be used to segregate drainage areas if sloping is not practical. However, since curbs are a personnel tripping hazard and can restrict access for maintenance, they shall be avoided wherever possible.

3.8.3.4. Heater Area Drainage

All surface drain catch basins, except dry box catch basins provided for heater area drainage, shall be equipped with a fire seal as specified in EPT 02-T-05. This prevents the backflow of flammable gas and possible flashback if gas is ignited in the sewer.


© Mobil Oil, 1997 29 of 80

3.8.3.5. Open Drainage

Sumps and collection basins for open drainage systems shall be equipped with properly terminated vents.

3.8.3.6. Floor Drains in Buildings

There shall be no floor drains in control rooms or adjacent laboratories.

3.8.4. Administrative and Shop Area Drainage The sewer shall be designed so that flow through the system will be from administrative and shop areas toward the process and tank field areas.

3.8.5. Open Drainage Ditch Design

3.8.5.1. Basis

Drainage ditches or trenches may be used for offsite storm water or firewater runoff, but shall not be used as part of a process sewer system. Location of the drainage ditch, relative to equipment and piping, shall be carefully considered to prevent fire exposure in the event of a flammable -liquid fire in the ditch.

3.8.5.2. Process Areas

Drainage trenches are not allowed in process unit battery limits to avoid collection and spread of flammable vapors to an ignition source that could cause a fire to spread throughout the trench system.

3.8.5.3. Design

Drainage ditches near pipeways containing hydrocarbon, firewater or utility lines shall be arranged as follows:

• Drainage trenches shall not be located under pipeline sleepers.

• Separate sleepers containing pipelines from trenches by a minimum of 15 m (50 ft).

• Pipeways crossing drainage trenches shall be protected by a concrete slab or culvert, or the piping shall be provided with fireproofing insulation. Use only continuous pipe or welded joints, avoiding flanged or threaded connections or fittings.

3.8.5.4. Ditch Roadway Crossings

Ditch crossings for roadways shall consist of a roadway culvert at least 9 m (30 ft) in length, arranged with a fire stop on one end. In cold climates, steam, glycol or electrical heat tracing of fire seals shall be provided to prevent freeze -up.


© Mobil Oil, 1997 30 of 80

3.8.5.5. Fire Stops

Fire stops between areas shall be of the inverted weir, downward elbow, or other design providing a water seal at least 152 mm (6 in) deep. The seals shall be designed to facilitate cleaning and removal of silt and debris.

Appendix A of NFPA 15 contains drainage ditch design data.

||Start E&P Only

3.8.6. Drains–Offshore Platforms A separate drainage system shall be provided for open drains. These include deck drains and utility room drains.

A separate drainage system shall be provided for closed drains. These include the following:

• Blowdown drains from high pressure vessels

• Blowdowns from level gauges

All open drains shall be equipped with a fire seal to prevent back flow of flammable gas.

All drains sha ll be designed according to API RP 14E.

3.8.6.1. Sumps and Collection Basins

• Sumps and collection basins for open drainage systems shall be equipped with vents terminating at a safe location.

• Sumps and collection basins for open drainage systems shall be vented to the platform flare or vent system.

End E&P Only||

3.9. Ventilation and Pressurization

3.9.1. Basis Ventilation shall be provided for buildings (enclosures) that contain hydrocarbon processing equipment.

3.9.2. Area Classification

Adequate ventilation used to reduce area classification shall be provided in accordance with API RP 500.


© Mobil Oil, 1997 31 of 80

3.9.3. Air Intakes If possible, air intakes for ventilation shall be located in an electrically unclassified area. As a minimum, the source of air shall be from an area classified no higher than the area to be ventilated.

When locating air intakes for building ventilation, consideration shall be given to potential sources of toxic and flammable vapors. In hydrocarbon processing areas, air intakes shall be elevated at least 7.6 m (25 ft) above grade.

3.9.4. Unclassified Electrical Equipment A building or enclosure that contains unclassified electrical equipment or other potential ignition sources shall be pressurized when it is located in an area that is electrically classified. The pressurization system shall be designed to maintain the building or enclosure at positive pressure. (Refer to MP 33-P-06 and NFPA 496.) An alarm shall be provided to indicate low building pressure.

||Start E&P Only

3.9.5. Pressurized Enclosures The following buildings or enclosed modules on offshore platforms shall be pressurized:

• Living quarters

• Control rooms

• Electrical facility rooms (switch gear)

• Communications building

• Satellite instrument houses

• Other similar buildings that may contain a potential ignition source (Forced ventilation with automatic shutdown louver can be used with the approval of ExxonMobil.)

3.9.6. Navigation Aids Navigation aids shall be installed as specified by MP 33-P-28.

Since navigation aids must be functional at all times, electrical equipment shall be suitable for Class I, Division 2, Group D atmospheres. This prevents the potential for an ignition source in the event of a major hydrocarbon release.


© Mobil Oil, 1997 32 of 80

Provision shall be made for safe access to permit inspection and maintenance of all navigation aids.

End E&P Only||

3.10. Signs

3.10.1. Basis Signs shall be used to promote ease of hazard, operation and procedure recognition and to avoid confusion during an emergency.

3.10.2. Objective Safety and health signs shall be used to:

• Warn of particular hazards

• Indicate required precautions

• Provide instructions

• Convey information

3.10.3. Scope Signs shall indicate the following:

• Hazardous materials and associated hazards

• Personal protective equipment required and its location

• Fire or emergency equipment use and its location

• Dangerous operations

• Access/egress facilities

• Equipment use

• Smoking areas

• Traffic control

• Facility identification

3.10.4. Placement Signs shall be placed as close to the area or equipment of coverage as possible. They shall be placed for optimum visibility.


© Mobil Oil, 1997 33 of 80

4. Fireproofing

The basic requirements for fireproofing applied to vessels, structures, buildings, walls, bulkheads and the supporting elements of equipment and piping in areas where flammable liquids and gases are processed, handled and stored are provided in MP 70-P-05.

5. Firewater Systems

Guidance on the provision of firewater systems and devices are established as a part of this EMEP. Design data and information for the installation of firewater supply, distribution and application systems and devices is provided in MP 70-P-07.

5.1. Provision

A firewater system shall be provided as depicted in the following Firewater System Decision Tree.


© Mobil Oil, 1997 34 of 80

Figure 4: Firewater System Decision Tree


© Mobil Oil, 1997 35 of 80

Figure 5: Firewater System Decision Tree (Continued)

5.2. Fire Hydrants

5.2.1. Location

5.2.1.1. Process Areas

Fire hydrants shall be located in process areas of onshore facilities on 45–60 m (150–200 ft) centers along accessways and roadways. Any portion of a unit shall be capable of being protected by a 64 mm (21/2 in) hose stream with 76 m (250 ft) of hose from adjacent hydrants. Hydrant locations shall be arranged to permit equipment to be reached from at least two opposite directions, so that manual hose line approaches can be made from the upwind side. Where appropriate, hydrants shall be positioned so that they may also be used to protect equipment in adjacent units or areas.


© Mobil Oil, 1997 36 of 80

5.2.1.2. Tank Farms

Tank farm fire hydrants shall be sized and located in accordance with NFPA 11 and MP 70-P-02 for foam requirements but this shall be no less than one hydrant for each tank quadrant.

5.2.1.3. Non-Process Areas

Hydrants in administrative, shop, plastic plant facilities and other non-process areas shall be located in accordance with NFPA 24.

5.2.1.4. Truck/Rail Loading/Unloading Racks

Hydrants or fire monitors shall be located no more than 30 m (100 ft) from all corners of a truck loading/unloading rack, as primary protection or as backup for a fixed system. For large rail car loading/unloading areas, hydrants shall be located on 30 m (100 ft) centers, at least 6 m (20 ft) from the rail line.


On piers and wharves, when hose streams will be used for primary protection, hydrants or wet barrel hydrants shall be located on 30 m (100 ft) centers.

One or two hydrants shall be located on the shore side of any division valves installed on long pier approaches. Onshore fire main systems shall have a hydrant located on the shore side of the isolation valve in the pier feed main.


Hydrants shall be located on all four sides of Expanded Group A Plastics bulk roll storage buildings. For such buildings located per NFPA 80A, without separation adjustments, the hydrant flowrate shall be at least 3785 L/min (1000 gpm). For such buildings located per NFPA 80A, including separation adjustments, hydrant flowrate shall be at least 7570 L/min (2000 US gpm).

End Chemical Only||

5.3. Firewater Monitors

5.3.1. Location

5.3.1.1. Onshore

Monitors shall be located as specified in Table 3 for fire control, vessel cooling and/or fire extinguishment. They shall be located to protect more


© Mobil Oil, 1997 37 of 80

than one piece of equipment. They may be used when more effective than a firewater spray system.

Table 3: Firewater Monitors

Type of Unit or Equipment Application of Monitors

Process unit towers For insulated column-type vessels, their reboilers and their hot oil piping and bottom connections.

Heat exchanger banks For channel sections (or expansion joints) and flanged connections when the unit contains high-pressure volatile for hot materials.

Process unit heaters For exposed return bends and crossovers and the area under the heater, to cool the structure and wash away spills.

Process unit air coolers For coolers when they contain liquids that are volatile and over 1.72 MPa gauge (250 psig) or materials over auto-ignition temperature.

Offsite pumps For offsite pumps in Class I or II hydrocarbon service. These shall be protected by one or two fixed water monitors positioned to cover both the pumps and adjacent pipe manifolds.

Pipeways and sleeperways Protect main pipeways and sleeperways vital to plant operation by strategically placed fixed water monitors arranged to wash away spills and/or cool adjacent piping in event of fire. (Fixed water sprays serve the same purpose but are more expensive to install and require more firewater).

Lube oil refineries For chillers, filters and similar equipment located outdoors and containing volatile flammable liquids in solvent extraction process.

Cooling towers For cooling towers locate to provide coverage of sides and top deck.

E&P facilities Cover all equipment within a fire designated area.

5.3.1.2. Offshore

For offshore facilities, fixed monitors shall be provided for protection of hydrocarbon-containing equipment in open areas of the platform. Where equipment congestion makes the use of monitors for equipment protection impractical, fixed water spray systems shall be provided in lieu of monitor protection.

5.3.2. Limitations and Location Guidelines Water monitors have the following limitations:


© Mobil Oil, 1997 38 of 80

• Water streams will be limited in reach of protected equipment when the opposing cross wind is 16 km/h (10 mph) or more.

• Reduced range of operation of up to 50 percent occurs in opposing or cross wind of 8 km/h (5 mph).

• Poor application or excessive use may overtax drainage facilities and/or spread fire from initial location. Water streams can be blocked by physical obstructions such as buildings, equipment or pipeways.

• Monitors located in areas subject to freezing shall be provided with freeze protection.

5.4. Portable Firewater and Foam/Water Monitors

Portable foam/water monitors may be provided for the locations listed in the following table.

Table 4: Portable Firewater and Foam/Water Monitors

Location Application of Monitors

Process units Firewater monitors may be used for cooling of equipment as necessary. At least two of the portable monitors provided for process area protection shall be of the foam/water type for combating major spill fires in crude and delayed coking units.

Tank fields Use portable foam/water monitors that protect process unit equipment for fighting diked enclosure fires, pipeway fires and cone roof tank fires. Fixed roof tank fires can be extinguished under favorable wind conditions when there is little or no updraft within the tank. A sufficient number of monitors are needed to satisfy a foam solution (a homogeneous mixture of water and foam concentrate in the proper proportions) application rate of 6.5 L/min/m2 (0.16 US gpm/ft2) of tank liquid surface area. A 227 m3/h (1,000 US gpm) or larger foam/water monitor may be used in this service when used with a fire truck.

Piers and wharves Fixed and portable foam/water monitors are recommended for fire protection on piers and wharves.


© Mobil Oil, 1997 39 of 80

5.5. Live Hose Reels

5.5.1. Location

5.5.1.1. General

Live hose reels shall be provided in process areas to enable personnel to respond quickly to small fires and to provide cooling streams for larger ones. Numbers and placement shall be such that any hydrocarbon process or accumulation of flammable material can be reached from two independent directions.


On piers/wharves handling tankers over 50,000 DWT, a live hose reel shall be provided at a convenient strategic position adjacent to each loading arm or cargo hose location. More than one loading arm or cargo hose location can be served by the same hose reel.

5.5.1.3. Multistoried Buildings

Multistoried buildings shall have standpipe systems designed in accordance with NFPA 14, Class II servic e, and shall have fire department pumper connections. If a separate system is used for hose reel supply, an outside control valve shall be installed.

5.5.1.4. Plastic Plants and Warehouses

Live hose reels shall be provided throughout plastic plants and warehouses in accordance with MP 70-P-07 and NFPA 15.

5.5.1.5. Cooling Towers

Cooling towers shall be provided with a live hose reel on the top deck, convenient to the stairway landing. In nonfreezing climates, this can be directly connected through a shutoff valve to the fire main system. In freezing climates, a 100 mm (4 in) standpipe with a hose connection at the base of the cooling tower shall be provided. This standpipe can be connected to the nearest fire hydrant or truck by means of fire hose if a fire occurs.

5.5.1.6. Offshore Locations

Live hose reel stations shall be provided in readily accessible locations, in and adjacent to process modules and wellhead areas, for the control of incipient stage fires. They shall also be provided at each level of the living quarters at opposite ends of the corridor, preferably in a stairwell. If the corridor length exceeds 46 m (150 ft), an additionally live hose reel station shall be provided halfway down the corridor. Live hose reels shall be provided to service the top landing and helideck where refueling is performed, when specified by ExxonMobil. If specified, these hose reels


© Mobil Oil, 1997 40 of 80

shall be capable of discharging Aqueous Film Forming Foam (AFFF) or water.

5.6. Automatic Sprinkler Systems

5.6.1. Warehouses Automatic sprinkler protection shall be installed in warehouses where combustible materials and/or combustible packaging are used. Normally, an automatic wet pipe sprinkler system shall be installed. However, where temperatures may drop below freezing, a pre-action system shall be used.

Warehouse sprinkler systems shall conform to NFPA 13 and NFPA 231C. Sprinklers for flammable and combustible liquid storage shall also conform to NFPA 30, Appendix D.


5.6.1.1. Manufacturing Areas

Automatic sprinkler protection shall be provided throughout the manufacturing area and shall be designed on the basis of 20.4 l/min/m2 (0.50 US gpm/ft2), hydraulically calculated for an area of 279 m2 (3,000 ft2). Work-in-process rolls in process areas and finished goods in manufacturing areas shall be limited to 93 m2 (1,000 ft2). Aisle separation between piles shall be 3 m (10 ft).

An automatic sprinkler system, designed in accordance with NFPA 13, extra-hazard occupancy and A/E Design Guide requirements, shall be installed for protection of the enclosed pentane pump room against fire or explosion. When an automatic sprinkler is installed, explosion venting shall be provided in accordance with NFPA 68.

End Chemical Only||

5.6.2. High Rise Warehouses Automated warehouses may be as high as 30 m (100 ft), requiring special fire protection considerations that are not specifically covered in current standards. Therefore, sprinkler system densities, and in-rack sprinkler arrangements must be determined on an individual basis. Sprinkler protection for noncombustible storage shall be based upon economic evaluation relative to fire risk and local codes. Sprinkler systems shall comply with NFPA 231C.


© Mobil Oil, 1997 41 of 80

5.6.3. Computer Rooms For protection of computer rooms, a pre-action or wet pipe system may be used. Wet pipe sprinkler protection is recommended for non-computer areas, such as customer engineering shops, offices, paper storage and tape libraries. No unsupervised valves shall be installed in risers downstream of the alarm check valve.

Water control valves shall be fully supervised and trouble signals shall be annunciated at the fire alarm control panel or equally appropriate location. Operation of the water valve supervision system shall not ring evacuation alarms.

Wet pipe sprinkler systems shall be provided with an approved retard chamber to minimize false alarms.

Sprinkler systems protecting computer rooms preferably shall be valved separately from other sprinkler systems.

To minimize water damage to electronic computer equipment located in sprinkler protected areas, power must be shut off prior to application of water on the fire. In facilities that are under the supervision of an operator or person familiar with the equipment (during all periods that equipment is energized), the normal delay between the initial outbreak of a fire and the operation of a sprinkler system will provide adequate time for operators to shut down the power by use of the emergency shutdown switches. In other instances where a fire may operate sprinkler heads before discovery by personnel, a method of automatic detection shall be provided to automatically de-energize the electronic equipment prior to water discharge from a sprinkler head.

5.6.4. Alarms All sprinkler systems shall be provided with water flow alarms that sound locally, in addition to a plant-controlled proprietary alarm center meeting NFPA 72 requirements or to a central station service. Water flow supervision shall be provided on all risers and separately annunciated to the alarm panel. Flow vane or paddle switches used in pre-action systems shall be located in the supply piping.

5.7. Firewater Spray Systems

5.7.1. General Fixed water spray systems shall be provided for protection of equipment against hazards involving gaseous and liquid flammable and combustible fires. Additional water spray systems shall be provided if dictated by local conditions, such as extreme exposure hazards or inferior process design or materials of construction.


© Mobil Oil, 1997 42 of 80

Transformers and pipe racks do not require water spray protection unless warranted by a hazard analysis.

Design and installation of fixed firewater spray systems shall be in accordance with MP 70-P-07 and NFPA 15.

5.7.2. Cooling Applications Non-insulated reactors, internally insulated reactors, non-insulated vessels, unprotected vessel skirts, unprotected supporting structural steel, vessels containing Class I liquids or liquefied gases and instrument trays/conduit runs shall be cooled by water spray impinging on and flowing over the protected surfaces. Vessels, supporting structures and instrument runs need not be provided with water sprays where provided with fireproofing or vapor depressuring. Refer to Section 9.4 of this EMEP.

When water spray systems are provided in lieu of fireproofing, automatic application of water spray by heat-detecting devices or UV/IR detectors shall be provided to ensure that protection is provided before serious weakening or collapse of the steel occurs.

Water film may be used in lieu of spray nozzles on pressure spheres where saturated hydrocarbons (butanes and lighter), which do not produce carbon deposits when burning, are being stored in the vicinity. With a water film, the sphere surface is thoroughly wetted by water discharging through a notched weir at the top of the sphere.

5.7.3. Fire Intensity Control Fire intensity control water spray shall be provided where fires are likely to originate from leakage or where effective fire fighting would be unusually difficult or dangerous.

Fire intensity water sprays shall be provided for pumps and compressors under the following conditions:

• When handling hydrocarbons at temperatures of 260°C (500°F) or higher.

• When handling flammable liquids at pressures higher than 3450 kPag (500 psig).

• When located beneath air coolers or within 3 m (10 ft), measured horizontally, of the projected outer edge of the air coolers while handling LP gas or Class I and Class II hydrocarbons with flash points below 60°C (140°F), or with flash points of 60°C (140°F) or above if the operating temperatures are above their flash points.

• Hot oil manifolds, (over 260°C or 500°F) or high pressure manifolds (over 3450 kPag or 500 psig) containing flammable liquids shall be protected by fire intensity control water sprays. Water sprays may be


© Mobil Oil, 1997 43 of 80

specified when a manifold is located in a congested area and contains numerous valves, flanges and regulators or when it contains strainers that are bypassed and opened for cleaning during operation of the unit.

• Filter boot pumps handling flammable liquids in lube oil plants. When filters are located in a building, fire intensity control water sprays over sight ports shall also be provided.

• A compressor lube oil console shall be protected with a water spray system which shall be activated separately from the compressor's water spray system unless the lube oil console is located within 6m (20 ft) of the compressor.

5.7.4. Prevention of Vapor Cloud Formation/Ignition Water sprays shall be used in areas where release of light ends (butanes and lighter) may occur in order to prevent a potential gas release from being ignited; for example, at high pressure pump and vessel connections, pipe fittings where pressures exceed 3450 kPag (500 psig), high pressure compressors operating above 3450 kPag (500 psig) and equipment located near ignition sources such as heaters. Sprays shall also be located, when specified, in areas where highly toxic materials could be released to the atmosphere.

To prevent formation of some toxic vapor clouds, such as HF, a specifically designed system with a greater water density is required. An expert in toxic vapor cloud mitigation systems shall be consulted.

5.7.5. System Design Fixed water spray systems shall be designed, installed and tested in accordance with MP 70-P-07, NFPA 13 and NFPA 15.

5.7.6. Activation Automatic detection and operation shall be provided when:

• Materials that are not resistant to thermal shock, such as cast iron valves or manifolds, are being protected.

• A fire must be controlled or extinguished in its first stage to prevent uncontrolled spread.

• The equipment handles highly toxic materials and water spray is required.

• Limited manpower is available or the facility size is such that the effective use of a water spray system is negated by a delay in manual activation time.

Remote manual operation shall be provided when automatic operation is not required and the valve manifold is within 50 ft of the perimeter of the fire


© Mobil Oil, 1997 44 of 80

hazard area. The remote actuation point shall be located at least 50 ft from the perimeter of the fire hazard area.

All other systems shall be manually operated.

5.8. Foam and Foam/Water Spray Systems

5.8.1. Basis Fixed foam and foam/water spray systems shall be designed according to NFPA 11.

5.8.2. Application Foam/water sprinklers shall be used for protection of tank truck loading racks.

Foam/water sprinklers may be considered for protection of:

• Pump houses and valve manifold pits

• Buildings storing materials subject to Class A and Class B fires

• Congested areas that are beneath, or immediately adjacent to, light hydrocarbon vessels and in which valuable equipment is located

5.8.3. Below Deck Foam/Water Sprinkler System Below deck foam/water sprinkler systems shall be provided for piers or wharves constructed of wood or non-fireproofed steel where the structure extends away from the shore or has a configuration that would complicate fire fighting.

5.9. Hose Carts and Houses

5.9.1. General Hose carts or hose houses are used where a plant lacks hose carrying ability on a fire truck. Where required, the carts or houses shall be provided in process areas for immediate use.

5.9.2. Design Hose carts or houses shall contain essentially the same equipment. Typical hose house designs are described in NFPA 24.


© Mobil Oil, 1997 45 of 80

5.9.3. Hose Cart Application Where possible, the carts shall be positioned for the common protection of adjacent units or areas.

5.9.4. Placement

Place carts adjacent to a hydrant in an area where it is not subject to collision damage, steam condensate and oil drips and from where it can easily be pulled toward a fire or onto a road.

6. Special Systems–Clean Agent, CO2, Twin Agent, AFFF and Dry Chemical Systems

6.1. General

The selection and installation of clean agent extinguishing systems shall conform to NFPA 2001.

6.2. Gas Turbines–CO2

6.2.1. System Selection Gas turbines shall be provided with fire and explosion prevention.

6.2.2. System Design The CO2 system shall be designed in accordance with NFPA 12. This system shall store sufficient CO2 to discharge at the required application rate. Discharge shall continue until all forced or induced ventilation airflow has ceased, while maintaining an inert atmosphere within the enclosure. Adequate precautions shall be built into the system (e.g., interlocks, predischarge alarms, etc.) to protect personnel who may be in the enclosure.

The CO2 system shall be tripped by combustible gas detection. Detectors with remote readout shall be provided. The combustible gas detection system shall sound alarms at 20–25 percent of the LEL. The alarms shall sound both locally and at a more remote, constantly manned location, where the analyzer shall be mounted for easy readout. The gas detection system shall shut down the ventilation system, shut off fuel to the turbine and trip the CO2 system at 50–60 percent of the LEL on a single detector or 20–25 percent of LEL on two detectors.


© Mobil Oil, 1997 46 of 80

In addition to gas detection, fire detection by means of fixed temperature detection and/or flame (UV/IR) detection shall be provided. The fire detector shall sound an alarm at a constantly manned location, shut down the ventilation system and shut off fuel to the gas turbine.

The fuel shutoff valve to be tripped by gas or fire detection shall be steel and shall be located adjacent to, but outside, the acoustical enclosure.

6.3. Computer Rooms–CO2

6.3.1. System Selection In general, carbon dioxide systems are not recommended for the protection of computer rooms. However, if a CO2 system is provided, it shall be designed per the provisions of this Section.

6.3.2. System Design

• The system shall be designed in accordance with NFPA 12. The system design shall be such that CO2 is distributed from a central bank of cylinders. Individual modular units dispersed throughout the protected area are not allowed.

• Automatic systems shall also be provided with a remote means of initiating CO2 discharge using a manually actuated electrical switch. This manual activation shall be outside the protected area and easily accessible to personnel. The manual release shall be prominently identified by a plastic or metal sign that will include hazardous zone locations and other pertinent data.

• Standby emergency power for initiating CO2 discharge need not be provided if a mechanical means is provided on the storage cylinders, transfer valves and other control equipment, and if the CO2 cylinder and control equipment are located outside the protected area. A prominent plastic or metal sign shall be located on all mechanical releases clearly indicating use, including sequence of operations, zones protected by each cylinder bank and safety instructions required.

• Operation of the CO2 system shall be interlocked to shut down the air conditioning system. The CO2 system shall be sized to compensate for the additional capacity equal to that exhausted by the air handling system. Air handlers that recirculate air within the CO2 protected area may remain operational after CO2 discharge.

• It is not necessary to de-energize electrical equipment prior to discharge of CO2.

• Alarms shall be provided to give positive warning of imminent discharge of CO2. A time delay device, set to give sufficient time to safely


© Mobil Oil, 1997 47 of 80

evacuate occupants of the protected space before discharge occurs, shall be installed in the system.

A room leakage test in accordance with NFPA 12, will be conducted on each new system and major modification to the system or computer room.

6.4. Carbon Dioxide Systems

Carbon dioxide systems shall be engineered for specific hazards in accordance with NFPA 12. Personnel safety features shall be provided as described in NFPA 12.

6.5. Pier and Wharf–Twin Agent Dry Chemical/Aqueous Film Forming Foam Unit

In those situations where a fixed foam system is not provided on a pier or wharf and a potential exists for a spill fire, a dry chemical/AFFF system shall be installed as follows:

• The recommended twin agent unit shall contain a minimum of 680 kg (1,500 lb) of potassium bicarbonate dry chemical and 0.76 m3 (200 US gal) of AFFF solution arranged to discharge through twinned turret nozzles and two twinned hand lines for discharge of dry chemical or AFFF through the separate nozzles.

• The AFFF turret nozzle shall have a rated discharge of 40 m3/h (180 US gpm) and shall have an effective range of at least 30 m (100 ft). The dry chemical turret nozzle shall have a rated discharge of 18 kg/s (40 lb/sec) and shall be arranged to rotate 360 degrees to provide coverage of the hazard area from an elevated position. The nozzle shall be remotely controlled and shall provide a discharge pattern capable of covering at least 45 m (150 ft) with no wind. The turret nozzle shall be controlled by a pneumatically operated ball valve and the discharge valve shall be capable of providing 5-second bursts.

• The twinned hand lines shall be designed as specified in Section 6.6 of this EMEP.

• The dry chemical system storage tank shall be sized for a 30-second supply or a minimum of 680 kg (1,500 lb) of potassium bicarbonate, foam compatible dry chemical. The tank shall be an ASME stamped pressure vessel, with suitable relief valve piped to prevent plugging by powder prior to operation. The tank shall be designed with a manway for inspection and installation of internals. To permit rapid filling with minimum loss, a quick-opening type manway for powder refill shall be provided on the top of the tank.

• The dry chemical tank shall be pressurized and powder fluidized by nitrogen. At least three 11.3m3 (400 ft3) approved type nitrogen storage cylinders shall be provided. The number of cylinders must be sufficient to operate the system when the average cylinder pressure is initially at 10.4 MPa gauge (1,500 psig). Each cylinder will have a quick-opening, pneumatically operated valve and pressure reducing valve to supply nitrogen at design pressure to the dry chemical tank. Sufficient nitrogen shall be available to blow the piping and turret nozzle free of powder after the powder has been discharged. The design shall also permit blow out of the system without further


© Mobil Oil, 1997 48 of 80

powder discharge when the tank is partially discharged. The design shall permit powder discharge at the design rate through the turret nozzle until at least 95 percent of the total supply has been discharged. Pressurization of the dry chemical tank shall be accomplished by remote, pneumatic operation at the nitrogen cylinders. Small carbon dioxide cylinders of the type used to pressurize portable hand fire extinguishers can be used to pneumatically actuate the system. Actuating stations shall be strategically located at the turret nozzle operating position.

• The AFFF solution tank shall be an ASME stamped (or equivalent) pressure vessel lined or of material that is recommended by the foam concentrate vendor for corrosion resistance. The tank shall be pressurized in the same manner as the dry chemical storage tank using at least one 11.3 m3 (400 ft3) nitrogen storage cylinder. There shall be sufficient nitrogen to blow out the piping system, hose and nozzle after use.

6.6. Twin-Agent Hose Reels

Twin-agent hose reel units incorporating dry chemical and AFFF shall be located to supplement water sprays, monitors and water hose reels for attack of hydrocarbon spill fires. Twin-agent hose reels shall be placed so that portions of a process unit that can accumulate spilled liquid hydrocarbons are accessible to the application of dry chemical twinned with AFFF from at least one dual-agent hose reel. Arrangement of the dual-agent hose reel shall be as follows:

• The recommended twin agent unit shall contain a minimum of 680 kg (1,500 lb) of potassium bicarbonate dry chemical and 0.76 m3 (200 US gal) of AFFF solution arranged to discharge through two twinned hand lines for discharge of dry chemical or AFFF through the separate nozzles.

• Twinned hand lines shall consist of 30 m (100 ft) of 25.4 mm (1 in) and 19 mm (3/4 in) dry chemical "engine" hose, joined and stored together on a live hose reel of the approved type. The 19 mm (3/4 in) hose is used for dry chemical and the 25.4 mm (1 in) hose for AFFF.

• The 25 mm (1 in) AFFF hand line nozzle, which is twinned or mechanically joined to the 19 mm (3/4 in) dry chemical hand line nozzle, shall have a discharge rate of 13.6 m3/h (60 US gpm). The 19 mm (3/4 in) dry chemical nozzle shall have a discharge rate of about 2.27 kg/s (5 lb/s).

• The dry chemical tank and AFFF solution tank shall be designed and installed as specified in Section 6.5 of this EMEP.

6.7. Kitchen and Galley Grease Hoods–Fixed Dry Chemical

Kitchen and galley grease hoods and exhaust systems shall be protected by a fixed automatic dry chemical fire extinguishing system as specified in NFPA 17, Paragraph 6–3 and NFPA 96, Chapter 7.


© Mobil Oil, 1997 49 of 80

7. Hand-Portable and Wheeled Fire Extinguishers

7.1. Basis

Fire extinguishers shall be provided and located in accordance with NFPA 10 and MP 70-P-11.

7.2. CO2

Portable CO2 fire extinguishers shall be provided for electrical fires in computer rooms, instrument houses, etc. A minimum of two CO2 fire extinguishers shall be located within 15m (50 ft) of each equipment cabinet. In addition, a minimum of three extinguishers shall be available at the main entrance to the facility, or suitable alternative location, for fire brigade use.

Each equipment area shall be provided with a fire extinguisher having a minimum rating of Class 2A for use on fires involving ordinary combustibles such as paper and plastic.

8. Detection and Alarm Systems

Design and application requirements for detection systems sensing fire, flammable/combustible gases and toxic gases are provided in MP 70-P-09.

9. Process Safety

9.1. Battery Limit Valves

Shutoff valves of the rising-stem type shall be installed on all hydrocarbon lines, including flare lines, at process unit battery limits.

• They shall be installed in a safe, easily accessible location and shall be clearly identified.

• Two means of access shall be provided to battery limit valves.

• Valves installed in flare lines shall be oriented with the stem in the horizontal position.


© Mobil Oil, 1997 50 of 80

• Figure-eight line blinds shall be provided on the process unit side of each shutoff valve.

• Valves located in an elevated pipeway shall have platforms provided for easy access to valve handwheels.

• Access stairways or caged ladders shall be installed at each end of the platform, on opposite sides of the pipeway.

• Each valve shall be clearly identified by sign and/or coding.

9.2. Safety Instrumented Systems

Safety Integrity Levels (SIL) for Safety Instrumented Systems (SIS) are discussed in MP 32-P-07 and are required by ANSI/ISA S84.01-1996, IEC 61508-1 Ed. 1 and IEC 61508-2 Ed. 2. The SIL shall be commensurate with the hazards posed by the process system. SIS/SIL analysis methods are discussed in MP 70-P-03.

9.3. Heater, Fired Reboiler and Combustion Safety Controls

9.3.1. Combustion Safety Controls Combustion safety controls for fired heaters shall be provided. Design details are specified in MP 32-P-09.

9.3.2. Heater and Fired Reboiler Protection

9.3.2.1. Backflow Prevention

To protect heaters and fired reboilers from fire in the event of a tube rupture, provisions shall be made to prevent backflow from the process train and for shutdown of fuel to burners and process feeds to the equipment. Fire control using depressuring, steamout and firebox steam purge shall be considered.

In noncoking service, when the operating pressure is greater than 690 kPa gauge (100 psig), a check valve shall be installed in the heater-tower, heater-reactor, or fired reboiler-tower transfer line—refer to EPT 09-T-04. This applies to all except catalytic reformer heaters, where the arrangement of charge and reheat lines makes the requirement impractical.

In coking service, when the operating pressure is greater than 690 kPa gauge (100 psig), a remote-operated block valve shall be installed in the transfer line.


© Mobil Oil, 1997 51 of 80

9.3.2.2. Burner Fuel Shutoff

On all heaters and fired reboilers, burner and pilot safety shutoff valve actuation shall be at least 15 m (50 ft) away and adjacent to the purge steam actuation, in accordance with MP 32-P-09. Each actuation station shall include a prominently displayed sign indicating function and the equipment controlled.

9.3.2.3. Steamout

• Where steam systems are available, steamout connections shall be provided on inlet and outlet piping—refer to EPT 09-T-04; on multipass heaters, they shall be provided on the inlet and outlet of each pass.

• Steam at 690–1380 kPa gauge (100–200 psig) shall be used.

• A check valve and double blocks with bleed valve shall be provided at all steam out connections.

• All connections shall be made to avoid trapping water on the coil side of the connection.

• The steam side of the connection shall be steam trapped to prevent collection of condensate.

• In coking service, where transfer-line check valves are not provided, steam introduced at the heater coil outlets prevents inventory backflow through the heater from the process train.

• Steamout connections are not required on reformer heaters.

9.3.2.4. Feed Shutdown

Facilities shall be provided to shut down heater or fired reboiler feed and any recycle streams from the control room or at least 15 m (50 ft) away from the heater or reboiler. Manual shutdown valves may be provided if they are less than NPS 8 and are at least 15 m (50 ft) from the heater or fired reboiler. Field remote actuation stations shall include prominently displayed signs indicating function and equipment controlled.

9.3.2.5. Damper Control

A remote stack damper control station, located adjacent to the purge steam actuation station and at least 15 m (50 ft) away from the heater or fired reboiler, shall be provided in accordance with MP 32-P-09. This shall be done where duties exceed 5.8 MW/h (20 MM Btu/h) and on all heaters sharing a common stack, regardless of duty.

9.3.2.6. Purge Steam

Firebox and heater purge steam shall be provided from a purge steam header at least 15 m (50 ft) away from the heater or fired reboiler, in accordance with MP 32-P-09.


© Mobil Oil, 1997 52 of 80

9.3.3. Automatic Safety Shutdowns for Fired Equipment in Sulfur Units Automatic safety shutdowns shall be installed to protect fired equipment such as thermal reactors, in-line burners and incinerators.

9.3.3.1. Upset Conditions

Combustion air, acid gas, sour water gas and fuel gas (including pilot gas) to the thermal reactor, in-line burners (when installed) and incinerator shall be shut down for the following upset conditions:

a) Combustion air failure.

b) Acid gas low flow.

c) High stack gas temperature.

d) Low water level in waste heat boiler.

e) Incinerator flameout.

f) Low fuel gas pressure.

g) Sour water stripper off-gas low flow. (When sour water stripper off-gas and acid gas are fired together and the off-gas is low, plant shutdown is optional, depending on the quantity of off-gas being fired in relation to the quantity of acid gas.)

h) Thermal reactor flameout or high temperature.

9.3.3.2. Flame Scanners

When operating on fuel gas, the thermal reactor and incinerator shall be equipped with a flame scanner to detect a flameout. On flame failure in any fuel gas fired burner, fuel gas and air flowing to that burner only shall be automatically shut down. Air and fuel gas will continue to be supplied to the remaining burners.

Flame scanners are required on fired equipment in order to prevent unburned fuel from entering the system when there is insufficient air to maintain a flame. The flame scanner shall not be interlocked to require a purge cycle on a hot start or when the H2S gas flow has not been interrupted. When the thermal reactor is operating on acid gas only and fuel gas is shut off, the flame scanner should sound an alarm.

9.3.3.3. Protection of Line Burners

Protection against flame failure of fuel gas supplied to line burners shall consist of interlocked flame scanners if the fuel gas is burned continuously. If the fuel gas is burned intermittent ly, flame scanners shall be installed and arranged for an alarm, provided interlocks are arranged to limit air relative to sour gas flow. This limit shall be 80 percent of the lower flammable limit.


© Mobil Oil, 1997 53 of 80

9.3.3.4. Optical Pyrometers/Thermocouples

An optical pyrometer and two thermocouples shall be installed in the thermal reactor. These will monitor temperature and provide flame failure detection when the reactor is operating on hydrogen sulfide only. Both thermocouples shall be used continuously in case one fails in service.

1. A low-temperature alarm based on the optical pyrometer shall sound in the control room when the temperature drops below 871°C (1600°F).

2. An interlock shall be provided to shut down the entire sulfur unit in the event of flame failure. This interlock shall be designed so that input from both the pyrometer and one or both thermocouples is needed for the shutdown. The system shall be designed to fail safe, so that the sulfur unit will also be shut down when these triggering devices fail.

9.3.3.5. Incinerator

The incinerator shall be protected by an ultraviolet flame scanner, which will shut down the sulfur unit on incinerator flame failure. The incinerator flue gas stack shall be provided with a high-temperature alarm that will shut down the sulfur unit if the operator takes no action within three minutes after the alarm is activated.

9.3.3.6. Air Blower Control Valves

The air blower control valves shall be located to prevent hydrogen sulfide from backing up and going to the atmosphere through the blowoff vent or suction if the blower fails. The control valves shall be designed to close on loss of air to the valve diaphragm or loss of power to a motor-operated valve. A check valve shall also be installed on the discharge side of the blower downstream of the branch connection to the blower anti-surge line.

9.4. Pressure Vessel Fire Protection

Pressure vessels shall be protected by either vapor depressuring, fixed firewater spray or fireproofing. Guidance on where to provide fireproofing can be found in MP 70-P-05; vapor depressuring can be found in MP 70-P-06; and fixed firewater spray protection is discussed in MP 70-P-07.

9.5. Emergency Shutdown

9.5.1. General The ability to progressively isolate hydrocarbon inventory, and depressure and shut down the process system is the preferred method of protecting hydrocarbon processing facilities.


© Mobil Oil, 1997 54 of 80

9.5.2. Emergency Shutdown Valves

9.5.2.1. Vessels and Pipelines

Emergency shutdown valves shall be provided on all hydrocarbon pipelines entering and leaving the facility and on vessel outlet lines located below normal operating liquid levels as shown in the following table.

Table 5: Normal Operating Liquid Levels

Material and Application Shutdown Valve Required for Vessels Containing:

Class IA and IB liquids 2,000 gal

Class IC and II liquids more than 300 psig, or more than 500°F, or at temperatures greater than autoignition temperatures

2,000 ga l

Class IC and II liquids (other than above) feeding single seal pumps, hose connections or drain lines

5,000 gal

Class I and II liquids feeding double mechanical seal pumps (equipped with seal failure alarms) or directly feeding another vessel (supercedes the first two categories above)

10,000 gal

Acutely toxic materials As evaluated by hazard assessment

9.5.2.2. Compressors

Emergency shutdown valves shall be provided on the suction and discharge of centrifugal and reciprocating compressors under the conditions specified in MP 15-P-04, MP 15-P-05 and EPT 09-T-04.

9.5.2.3. Fired Heaters

Where there is the possibility of a large fire as a result of a serious spill or leak, remote fuel shut-off shall be provided on fired heaters or reboilers located in or adjacent to process trains. This remote shutdown shall be controlled from a safe location at least 15 m (50 ft) away from the heater. The safety shutdown valves shall be actuated to close by a shielded push-button or rotating switch. An additional remote shut-off of fuel to the heater may be provided in the control room.

In addition to isolating fuel to a fired heater, facilities shall also be provided to shutdown charge and recycle lines to a fired heater or reboiler. This remote shutdown shall be controlled from the control room or from a safe location at least 15 m (50 ft) away from the heater. Manual shutdown valves


© Mobil Oil, 1997 55 of 80

may be provided if they are less than NPS 8 and are at least 15 m (50 ft) from the fired heater or reboiler.


For piers and wharves, all lines, irrespective of size, transferring hydrocarbons between the shore and a tanker or barge shall be provided with an emergency shutdown valve to prevent spills when cargo hoses or loading arms fail. Provisions for the emergency shutoff valve are as follows:

• Locate the valve in the piping system near the shore manifold connection to minimize spill size, at a location oriented toward the shore end of a pier or wharf.

• The valve shall be capable of being remotely actuated from locations that are strategically positioned on shore and on the pier or wharf.

• Lines dedicated only to flow toward shore may use an indicating type check valve to prevent back flow.

• Valve operators shall be either motor-operated or pneumatically actuated. The valves shall be provided with a reliable electric or pneumatic power supply. Electric cables and motors shall be fireproofed in accordance with MP 70-P-05. Pneumatic tubing shall be stainless steel. As an alternative, valves can be arranged to "fail-closed" on loss of electric or pneumatic power. Remote actuating stations can then be arranged to intercept power or vent air pressure to shut the valve.

• Maximum closing time shall be one minute or the time required by regulations.

• The piping system shall be evaluated for potential hydraulic hammer and precautions provided if necessary.

• Piping system shall also include, where feasible, manually actuated quick isolation valves to assist and/or back up remotely operated shutoff valves.

9.5.2.5. Valve Type

Shut-down valves of the rising-stem type shall be installed on all hydrocarbon lines, including flare lines, at process train (unit) battery limits in multi-train gas plants. Spectacle blinds shall be provided on the process unit side of each shut-off valve. Emergency shutdown valves shall be a "fail-closed" design. Emergency shutdown valves shall close upon fire detection and/or the appropriate process upset condition. Consideration shall be given to automatic shutdown for events such as fire, release and/or according to hazard analysis.

9.5.2.6. Location and Access

Valves shall be installed and clearly identified in a safe, easily accessible location. Valves located in an elevated pipeway shall have platforms


© Mobil Oil, 1997 56 of 80

provided for easy access to valve hand wheels. Caged access ladders shall be installed at each end of the platform, on opposite sides of the pipeway. Each valve shall be clearly identified by a sign and/or coding.

9.5.2.7. Pipeline

A positive method of indicating the position of pipeline emergency shutdown valves shall be provided at the control point of the facility.

||Start E&P Only

9.5.2.8. Safety Valves

• Surface-controlled subsurface safety valves shall be designed and installed to meet the minimum requirements of API RP 14B.

• Surface safety valves shall meet the minimum design and arrangement requirements of API RP 14C.

• Valves designed to close automatically upon activation of the shutdown system, shall be provided as specified in API RP 14C.

9.5.2.9. ESDVs/SSIVs

ESDVs on pipeline risers shall close upon activation of a Class 1 or Class 2 shutdown.

• A positive method of determining the operational position of pipeline ESDVs shall be provided at the control point on manned platforms.

• The location and the integrity of ESDV operations on risers shall not be impaired by any fire, explosion or similar incident originating from the platform (as demonstrated by the hazard assessment conducted with MP 70-P-03).

• Where indicated by a hazard assessment, subsea isolation valves or check valves shall be installed in subsea pipelines.

• Subsea isolation valves (SSIVs) shall be activated by a remote manual system from the associated platform, if manned, or from the nearest manned facility if the associated platform is unmanned.

The location of SSIVs shall be determined as a part of the hazard assessment.

9.5.3. Shutdown Systems

9.5.3.1. Offshore Platform Shutdown/Depressuring Systems

Each platform shall have a shutdown and depressuring system structured with at least two levels.


© Mobil Oil, 1997 57 of 80

9.5.3.1.1. Level 1

This level involves full production shutdown, activated manually. The associated major actions shall be as follows:

1. Closure of the subsurface and surface safety valves on all production injection wells.

2. Shutdown of the processes and all ESDVs, including those on the top of pipeline risers.

3. Electrical isolation of all except the following devices, and the electrical supply necessary to operate them: emergency lighting, navigation aids, fire and gas detection, fire protection, UPS and the communication systems.

The activating stations shall be located as specified by API RP 14C Appendix C.

Drilling systems shall not be included in a Level 1 shutdown. Instead they shall be equipped with a separate shutdown system.

The shutdown stations shall be protected against accidental activation as required by API RP 14C.

9.5.3.1.2. Level 2

This level involves a full production shutdown, activated automatically by a single fire detection signal from a pressurized fire loop system, as specified by API RP 14C. The associated major elements shall be as follows:

1. Activation of the fire loop signal shall result in the same shutdown and isolation actions as Level 1, when the system senses a fire in the presence of the wellheads and manifolds or when there is only one fire loop zone.

2. On larger more complex platforms with additional fire protection loops, only those events detected in the well head area need cause the subsurface control valve to close.

3. Depressuring provisions and actions shall be as noted for Level 1.

4. Gas detection shall be provided by detectors (one detector at 50–60 percent LEL or two at 20–25 percent LEL activated).

5. At least one upstream ESDV on each line entering the protected area shall close on confirmed gas detection.

6. Confirmed gas detection in the wellhead area will cause both surface and subsurface safety valves to close.

The extent of process shutdown shall depend upon the physical location of production vessels and equipment, their separation by physical barriers, the specific process flows and the design of the fire and gas system.


© Mobil Oil, 1997 58 of 80

End E&P Only||

9.5.3.2. Application

In process units, complex gas plants with more than one production train or where the plant performs a gathering function in addition to production, one or more levels of shutdown may be required. Such systems shall be analyzed to ensure that the shutdown and depressuring actions are consistent with the production and safety philosophy for the facility. The extent of sublevel shutdown(s) will be dependent upon the physical location of production vessels and equipment, their separation distances, the specific process flows and the design of the fire and gas detection systems.

9.5.3.3. Shutdown System Activation

The activation mechanism(s) for the shutdown system shall be based on the hazards present at the facility and the absence or presence of operating personnel and/or automatic detection and alarm systems. As a minimum, an emergency shutdown system shall have a manual push button for emergency.

In normally unmanned remote facilities, the emergency shutdown systems shall be activated by fire or gas detection systems as follows:

• By a single fire detection signal when automatic fire detection is required.

• By a signal from a combustible or toxic gas detection and alarm system when an automatic toxic or combustible gas detection system is required. Activation of the shutdown due to combustible gas detection shall require activation of one detector at 50–60 percent LEL or coincidental activation of two detectors at 20–25 percent LEL.

• By critical process instrument alarms, as determined by a process hazard analysis.

9.6. Relief and Depressuring

9.6.1. Application Process units and those portions of the production system downstream of the wellheads shall be provided with pressure relief as specified by MP 70-P-06. Where a depressuring system is provided, it shall be designed in accordance with MP 70-P-06. There must be at least one depressuring valve for each section of the production system to be isolated. However, the number of such valves shall be kept to a minimum.

9.6.2. Depressuring Valves Depressuring valves shall be designed to fail open. Devices (i.e., back-up power) shall be provided to prevent the valves from opening before ESD has


© Mobil Oil, 1997 59 of 80

been initiated. When vulnerable to fire, a depressuring valve and its power supply shall be fireproofed in accordance with MP 70-P-05.

The activation mechanism(s) for depressuring valves shall be based on the hazards present at the facility and the absence or presence of operating personnel and/or automatic detection and alarm systems. As a minimum, depressuring valves shall be provided with a manual push button for emergency depressuring and a separate manual control for process depressuring.

In normally unmanned remote facilities, the depressuring systems shall be activated by critical process instrument alarms, fire or gas detection systems as follows:

• By a single fire detection signal when automatic fire detection is required.

• By a signal from a combustible or toxic gas detection and alarm system when an automatic toxic or combustible gas detection system is required. Activation of the shutdown due to combustible gas detection shall require activation of one detector at 50–60 percent LEL, or coincidental activation of two detectors at 20–25 percent LEL.

• By critical process instrument alarms, as determined by a process hazard analysis.

In continuously manned facilities, process system depressuring shall be manually activated, except where automatic activation is required by specific pieces of equipment due to their design.

10. Pipelines and Pigging Facilities

10.1. General

Provisions shall be made for the protection of pipeline emergency valves, valve actuators and pigging equipment including all of the following:

• ESDVs (Not Sub-Sea)

− Fire-rated valve body and seals

− Selection of single acting ESDVs (hydraulic or pneumatic to hold open, spring to close)

− Fusible plugs to release actuator pressure

− Placement of ESDVs and actuators to minimize exposure to risers from platform hazards


© Mobil Oil, 1997 60 of 80

• SSIVs: Selection of single acting valve

• Pipeline Risers: Impact protection from marine vessels

Pig Launchers and Re ceivers: Orientation of launchers and receivers so as not to "aim" at other equipment

10.2. Level of Protection–ESDVs and Related Equipment

The level of protection provided for pipeline emergency valves (i.e., ESDVs), valve actuators and related equipment shall be determined by hazard assessment techniques as described in MP 70-P-03, except as stated above.

11. Flame Arrestors

Flame arrestors shall be installed to prevent flashback of a flammable mixture on fired heaters, such as heater treaters, line heaters and glycol boilers. The flame arrestors shall be located in the process piping in accordance with the manufacturer's specifications, usually as close as possible to the ignition source.

Flame arrestors shall not be used on the end of flammable or combustible liquid storage tank vents, except when required by regulations. Instead, a pressure/vacuum relief valve shall be installed to minimize vapor emissions and provide flashback protection.

12. Explosion Prevention

12.1. Purging and Inerting Systems

Purging or inerting systems using fuel gas, nitrogen or carbon dioxide shall be used, where required, both to prevent fire and explosions and to avoid product contamination due to oxidation.

12.2. Explosion Suppression Systems

Explosion suppression shall be used, where required, to prevent deflagrations or detonations in equipment containing flammable air-vapor mixtures or combustible dusts when the possible presence of an ignition source cannot be prevented.


© Mobil Oil, 1997 61 of 80

13. Power Plants

13.1. General

Adequate fire protection is essential for steam and power generation facilities to ensure the required reliability in emergencies and prevent total refinery or petrochemical plant shutdown. Such protection shall meet the requirements of MP 41-P-09.

13.1.1. Steam Boiler Combustion Safety Controls The modern steam boiler, incorporating forced and/or induced combustion air, water-cooled walls and rapid steam generation, requires flame scanning with other safety interlocks (including air purge) for safe operation. Combustion safety controls shall be provided as specified in MP 32-P-12 for gas- or oil-fired, multiple -burner boiler furnaces and for single-burner furnaces.

These controls satisfy the requirements stipulated for multiple-burner boiler furnaces in NFPA 8502 for supervised manual operation. Requirements for single-burner furnaces are covered in NFPA 8501.

14. Buildings

14.1. Building Construction

New buildings shall be fire resistant, protected noncombustible, or noncombustible as defined in NFPA building construction standards and shall comply with MP 01-P-13 and the applicable portions of BOCA, except where local building code requirements are more stringent. Existing structures shall be provided with fire protection based on the degree of hazard and building construction.


14.2. Building Areas

Building areas between firewalls for both low-piled and high-piled storage shall not exceed 9,300 m2 (100,000 ft2). This area limitation is based on buildings covered by the fire protection systems. Plastic warehouses shall be limited to the areas specified in this Master Practice.


© Mobil Oil, 1997 62 of 80

End Chemical Only||

14.3. Fire Separations

Firewalls shall be located in buildings to limit fire areas. Firewalls shall be constructed in accordance with BOCA. Roof supports shall be designed so if the roof over one area collapses, it will not cause the firewall and roof over the adjacent area to collapse. Openings in firewalls shall be protected by automatic fire doors in accordance with NFPA 80.

14.3.1. Fire Divisions Fire divisions are designed to provide a fire resistive separation between adjoining spaces including those areas located above, below or in other adjacent (contiguous or abutting) structures, yard storage and process units. The prime purpose of the perimeter separation is to protect each area from the damaging effects of a fire outside of that area.

14.3.2. Fire-Rated Walls and Partitions Fire-rated walls or partitions shall extend from the structural floor to the underside of the structural floor or roof above.

14.3.3. Openings in Fire-Rated Walls and Partitions Openings in fire-rated walls or partitions shall be protected by fire doors, fire windows, fire dampers or glass block. Fire protection ratings of fire doors, fire dampers, fire windows and fire resisting glass block shall be as determined and reported by a nationally recognized testing agency in accordance with NFPA 252 for fire doors and NFPA 257 for window assemblies. The total area of all openings in a fire-rated wall or partition shall not exceed 25 percent of the total surface area between finished floor and ceiling.

14.3.4. Cable Openings Cable openings or other penetrations into areas shall be fire-stopped with material that has a fire rating equal to the fire resistance rating of the penetrated fire barrier.

14.4. Life Safety

Provisions for life safety shall be arranged in accordance with NFPA 101. Specific requirements are as follows:

1. Warehouse areas for finished products shall have exits arranged in accordance with NFPA Storage Occupancies.


© Mobil Oil, 1997 63 of 80

2. Office areas located in separate buildings, or separated by fire-rated walls or partition from areas, shall have exits arranged in accordance with NFPA 101.

14.5. Interior Hazard Segregation

No piping containing oil, flammable liquids, gases, toxic materials or high-pressure steam (> 1.04 MPa gauge [> 150 psig]) shall be installed in control rooms, washrooms or in similar locations. There shall be no floor drains in control rooms or adjacent laboratories. Piping, except steam heating piping, shall not enter switch rooms or be under the floor.

Consideration shall be given to providing protective covers or deflectors over gasketed and packed joints in piping containing acid, caustic and other hazardous chemicals where such lines are adjacent to walkways or work areas.

14.6. Central Control Facilities

Process facility central control buildings shall be located, designed and protected in accordance with MP 70-P-04 and MP 01-P-10. If required, a pressurization system designed in accordance with MP 33-P-06 shall be provided. Those areas which are determined to be critical to the safe control of the process shall be segregated by a 2–4 hour rated fire wall from:

1. Food preparation areas

2. Electrical switchgear and transformer rooms

3. Laboratories

In the event that a laboratory is located within a central control facility, both the HVAC and drainage systems shall be segregated, in addition to the fire-rated wall.

14.7. Exposure Protection

Where separation between structures is used in lieu of a properly designed fire wall, building separation distances shall be determined by calculation of the extent of fire exposure in accordance with NFPA 80.


14.7.1. Flammable and Combustible Substances Handling, storage and transfer of flammable and combustible liquids shall be in accordance with NFPA 30, except when more stringent requirements are set by MP 70-P-02. All areas for bulk handling of flammable and combustible liquids shall be separated from manufacturing, reclaim, warehousing and office areas by walls with a four-hour rating.


© Mobil Oil, 1997 64 of 80

Unless required by local codes, NFPA 30, NFPA 231 or NFPA 231D; determination of the need for a sprinkler protection shall be based on the following considerations:

1. Value of the product stored

2. Replacement cost of the building

3. Cost of business interruption

4. Hazard of the products stored

5. Fire exposure to and from off-site installations

6. Exposure to the public

7. Political and environmental consequences

14.7.2. Flammable Vapor Removal Flammable vapor removal systems, designed in accordance with NFPA 91, shall be installed to ventilate printing press and coating areas. Air flowrates shall be designed to maintain the areas at no more than 25 percent LEL of all solvents used in the process.

Flammable vapor removal systems, designed in accordance with NFPA 91, shall be installed to ventilate the extrusion die area. Air flowrates shall be arranged to maintain the area around the extruder and windup area at no more than 25 percent LEL of any flammable blowing agent. Failure of the ventilation system shall be signaled by an alarm to a manned location. Overall room ventilation for comfort and heating shall be separate from the flammable vapor removal system.

End Chemical Only||

15. Warehousing

15.1. General

Storage of flammable and combustible liquids inside buildings shall be in accordance with NFPA 30, NFPA 231 and NFPA 231C. Flammable warehouses meeting NFPA 30 are limited by pile size and arrangement for bulk quantities of flammable and combustible liquids in portable containers. Arrange automatic sprinkler protection for piled, palletized, rack and automated rack storage of flammable and all combustible liquids in accordance with NFPA 30, NFPA 231 and NFPA 231C. Flammable aerosols shall be stored as Class IA liquids as specified in NFPA 30. Storage of unpackaged noncombustible bulk materials (such as bulk chemicals, sand, catalysts and similar commodities) is not required to meet provisions of this Master Practice or NFPA 231.


© Mobil Oil, 1997 65 of 80

15.1.1. Automated Warehouses Warehouses for the general storage of combustible materials, including plastic materials piled 4m (12 ft) high, shall meet the requirements of NFPA 231C.

15.1.2. Manual and Forklift-Stacked Warehouses This Section applies to warehouses that are stacked manually or by forklift trucks. Warehouses for general storage of combustible commodities, including plastic materials pile (25 ft) or less in solid or palletized piles, shall meet the requirements of NFPA 231, if the building has sprinklers.

15.1.3. High-Piled and Rack Storage of Combustible Materials

High-pile warehousing of combustible materials greater than 7.6 m (25 ft) in solid piles, or palletized piles greater than 3.6m (12 ft) in racks, shall be arranged in accordance with NFPA 231C.

Storage of combustible materials in racks protected by automatic sprinklers shall have a system design in accordance with NFPA 231C, based on the appropriate commodity class. Mixed storage methods shall have protection designed for the higher degree of hazard.


16. Plastic Warehousing & Storage Areas

16.1. General

Storage of plastics shall be located in a separate building or fire area from the storage of flammable and combustible liquids.

16.2. Storage of Expanded Group A Plastics Bulk Rolls

Bulk quantities of Expanded Group A Plastic rolls, other than those required for immediate thermoformer operation or removal from extruder windup, shall be stored in a separate bulk roll storage building. The roll storage building shall be separated from manufacturing, product warehousing, or other plant operations by a minimum of 30 m (100 ft). Piles in manufacturing areas shall be limited to 93 m2 (1000 ft2). Aisle separation shall be 3 m (10 ft) between piles.


© Mobil Oil, 1997 66 of 80

Automatic sprinkler protection is not required for bulk roll storage buildings that are used to store only bulk roll plastics and that are separated from all other manufacturing and storage areas per Section 5.6 of this EMEP. Connecting tunnels between manufacturing and bulk roll storage areas shall be protected by an automatic sprinkler systems, hydraulically designed to provide 20.4 L/min/m2 (0.50 US gpm/ft2) over an area of 279 m2 (3000 ft2).

16.2.1. Solid-Piled Storage of Expanded Group A Plastics Products Building height shall be limited so that clearances between the top of the storage and the sprinklers do not exceed 3 m (10 ft).

a) Nonexpanded Group A Plastics: Solid-piled storage of Nonexpanded Group A Plastics shall be protected by an automatic wet-pipe sprinkler system, hydraulically designed in accordance with NFPA 13, NFPA 231 and A/E Design Guide requirements.

b) Expanded Group A Plastics: Solid-piled storage of Expanded Group A Plastics, up to 5.4 m (18 ft) in height, shall be protected by an automatic wet-pipe sprinkler system, hydraulically designed in accordance in NFPA 13, NFPA 231 and A/E Design Guide requirements. Piles shall not exceed 465 m2 (5000 ft2) in area and shall be separated from adjacent piles by aisles at least 2.4 m (8 ft) wide.

16.3. Warehouse Storage of Plastic Products in Racks

Building height shall be limited so that clearances between top of storage and sprinklers do not exceed 3 m (10 ft). Rack storage of plastic products requires sprinkler design conforming to the requirements of NFPA 231C.

• Storage in racks shall be protected by automatic wet-pipe sprinklers designed in accordance with NFPA 231C and A/E Design Guide requirements.

• Rack storage of Expanded Group A Plastics is not allowed.

16.3.1. Extrusion Areas Nonexpanded Group A Plastics extrusion areas that also include reclaim storage shall have automatic sprinkler protection meeting the requirements of NFPA 13 on the basis of an extra-hazard occupancy, or a hydraulically calculated system for 10.2L/min/m2 (0.25 US gpm/ft2) over an area of 279 m2 (3000 ft2) or the entire room if less than 279 m2 (3000 ft2).

Expanded Group A Plastics extrusion areas with reclaim storage shall have automatic sprinkler protection calculated for 20.4L/min/m2 (0.50 US gpm/ft2) over an area of 279 m2 (3000 ft2) or the entire room if less than 279 m2 (3000 ft2).


© Mobil Oil, 1997 67 of 80

16.3.2. Fluff Storage Bins Expanded Group A Plastics fluff storage bins and similar types of equipment for storage of finely divided plastics shall be maintained at a negative pressure and shall be protected against fire and explosions. Fluff bins shall be explosion vented to the building exterior per NFPA 68. Where equipment design is such as to withstand the degree of pressure building, an explosion prevention system shall be installed in accordance with NFPA 69. Fire extinguishing systems provided shall utilize carbon dioxide or a suitable alternative, meeting the requirements of NFPA 12.

16.3.3. Oven and Dryers Where recycled air is passed through hot-air heater, ovens and dryers the duct work shall be arranged to prevent flammable vapors from entering the combustion zone. Additional design requirements shall conform to NFPA 86.

16.3.4. Exhaust Duct System Protection Fixed fire protection inside the extrusion die exhaust duct system may be needed because of the size, arrangement and inaccessibility of the system, and the potential damage to the plant by a duct fire. When needed, duct protection shall be provided by an engineered automatic carbon dioxide or dry chemical fire extinguishing system, automatic sprinklers or manually operated water spray system.

16.3.5. Reclaim Areas Fire protection considerations shall include building arrangement, measures for confinement of dust within handling equipment, reduction of ignition sources, explosion pressure relief and fire control. All areas involving plastic dust shall be arranged in accordance with NFPA 654. Reclaim areas shall be separated from manufacturing or warehouse areas by two-hour rated fire wall. Where possible, such areas should also be located along an exterior wall.

Granulating and fluff storage areas shall be isolated from the remainder of the reclaim operation by fire partitions. Granulating and fluff storage areas shall be provided with automatic sprinkler protection per NFPA 13 and explosion venting per Section 5.6.1.1 of this EMEP. If the granulating and storage areas cannot be effectively isolated, the entire area shall meet the requirements for explosion venting and extra-hazard sprinkler protection.

16.4. Pentane System Areas

The recommended location for pentane storage and unloading systems is outside of the building.


© Mobil Oil, 1997 68 of 80

16.4.1. Transfer Means shall be employed to prevent release of pentane in manufacturing areas or pentane rooms through broken piping in the pentane handling system. The piping system and all valves shall conform to the requirements of MP 16-P-31A.

16.4.2. Pump Rooms

All pentane pumps, piping manifolds and secondary storage tanks shall be located in a separate protected fire area, cut off from the manufacturing areas by a two-hour rated fire wall. Any necessary openings shall be protected by 11/2 hour (B) fire doors or damper, arranged in accordance with NFPA 80. A shutoff switch shall be provided outside the pump room to stop the flow of pentane in an emergency.

16.4.3. Fire Areas Building fire areas shall be established on the basis of area limits allowed in Table 6 for types of construction per NFPA 220 Type 1 only. These area limits are based on buildings provided with automatic sprinkler protection.

Table 6: Fire Area Limits

Building Use Fire Area Limit for Construction

Type 1 m2 (ft2)

Manufacturing: Nonexpanded Group A Plastics Expanded Group A Plastics

9290 3716

(100,000) (40,000)

Storage: Nonexpanded Group A Plastics Expanded Group A Plastics Finished Goods Rolled Storage Areas

9290 5574 5574

(100,000) (60,000) (60,000)

16.5. Rubber Tire Storage Areas

Rubber tire storage warehouse, or storage areas, are used to store more than 10,000 passenger tires weighing approximately 11.4 kg (925 lb) each, shall be arranged in


© Mobil Oil, 1997 69 of 80

accordance with NFPA. Fire protection for rubber tire storage shall be provided in accordance with NFPA 231D. Tire warehouses shall not exceed one story. Building heights exceeding 8.2 m (27 ft) to roof shall be avoided.

Fire walls shall be parapeted–not cut off level with noncombustible roof decks. Fire walls which have a six-hour minimum rating shall be provided with automatic-closing Class A fire doors on each side of the wall opening.

Fire protection shall consist of hydraulically designed automatic wet pipe sprinklers, in accordance with NFPA 13, to meet NFPA 231D requirements. Sprinkler spacing shall not exceed 9.3 m2 (100 ft2) per sprinkler using a staggered installation pattern.

In addition to automatic sprinkler protection, an automatic high-expansion foam system designed in accordance with NFPA 11A may be installed, depending upon the value of the stored tires, fire exposure warehouse, adjacent property installations, etc. MRDC may be consulted to determine the need for the system. Foam time shall not exceed seven minutes where building structural steel is unprotected minus where the building is of fire-resistive construction or all structural steel is fireproofed.

Small scale storage for rubber tires is used only as a replacement on ExxonMobil vehicles does not require sprinkler protection.

End Chemical Only||

16.6. Storage Containers

Storage containers and aids such as wood and plastic pallets, cardboard cartons, shrink wrap wood blocks, plastic and paper padding and plastic containers shall be treated as combustible storage. Storage materials in metal containers, or inert materials without combustible packaging, shall be treated as noncombustible storage.

16.7. Drainage

Warehouse storage of flammable or Class II or III combustible liquids requires special consideration of emergency floor drainage. The drainage shall meet the following requirements:

1. Size drainage for a minimum of calculated total sprinkler discharge plus 113 m3/h (500 gpm) streams.

2. Drainage area for application calculation is a minimum of 93 m2 (1000 ft2).

3. Trap drains or lead discharges to safe outdoor location such as a drainage system.

4. When using scuppers, liquids must be diverted to a safe area so as not to expose other buildings or equipment outside of the building.


© Mobil Oil, 1997 70 of 80

16.8. Smoke and Heat Venting

Smoke and heat venting with curtain boards shall be provided in all new storage buildings over 930 m2 (10,000 ft2), except in automated warehouses where curtain boards may not be feasible because of the equipment and overhead power systems.

Smoke and heat venting shall be designed in accordance with NFPA 204M, based on heat-release for limited-growth fires and characteristic growth times for continuous-growth fires. Maximum between curtain boards shall not exceed 30 m (100 ft).

16.8.1. Curtain Boards

Curtain boards to control smoke and heat venting shall extend down from the ceiling for a vertical depth of 1.8 m (6 ft).

• Materials for curtain boards shall be sheet metal, metal lath and plaster, noncombustible material that is not susceptible to shattering or spilling when exposed to heat.

• Curtains separating high-heat release materials storage areas from low-heat-release areas shall be at least 3.7 meters minimum vertical depth. This method of enclosure is acceptable only as an alternative when separation by fire partition or fire walls is not feasible.

• Locations that may require such separation include tire storage quantities adjacent to lube or grease storage, or flammable liquid containers stored adjacent to general storage.

Areas contained by curtain boards shall be arranged as follows:

1. Tire storage areas: curtained areas limited to 930 m2 (10,000 ft2)

2. Flammable liquid storage: curtained areas limited to 465 m2 (5,000 ft2)

3. Lubes, greases, combustible liquids: curtained areas limited to 930 m2 (10,000 ft2)

4. General combustible storage: curtained areas limited to 1860 m2 (20,000 ft2)

16.8.2. Venting

Unit type vents are preferred. Unit type vents are more economical and have increased effectiveness for smoke and heat removal. Units shall be approved by Underwriters Laboratories, Factory Mutual Laboratories or the equivalent outside of the U.S. (In areas where flammable or combustible liquids are stored, or where plastic containers are commodities in storage, stationary vents may not be adequate to release the high-heat buildup generated.) In such cases, powered vents shall be used. The fusible link operated vent or the plastic meltout type of vent, with appropriate fall protection, is


© Mobil Oil, 1997 71 of 80

recommended. Fusible link operated vents shall have a temperature rating of approximately 100°C (212°F).

17. Computer Rooms

17.1. General

The computer facility shall be located, constructed and/or protected to provide minimum exposure to fire, water, smoke and corrosive fumes from adjoining areas and activities.

17.2. Exposure Protection

Where the computer facility is exposed to a potential fire risk due to surrounding facilities, appropriate exposure protection shall be provided in accordance with NFPA 80.

17.3. Construction

17.3.1. Separate Fire Area The computer facilities shall be housed in a fire resistant, noncombustible building or in a fire separated area.

17.3.2. Interior Construction When areas in an existing structure are to be converted for use as a computer area, all nonstructural combustible materials within the equipment area shall be removed. All materials installed within the computer area including walls, floors, partit ions, finish acoustical treatments, raised floors, suspended ceiling, etc., shall have a flame spread rating of 25 or less (see NFPA 255). Exposed cellular plastics shall not be used in computer room construction.

17.3.3. Floor When raised floor systems are used in computer areas, they shall be installed as follows:

1. Flooring, decking and ramps shall be concrete, steel, aluminum or other noncombustible materials, except that minimum amounts of vinyl or rubber materials are permitted for leveling and sealing or to prevent horizontal shifting of floor panels or decking.

2. Flooring or decking shall consist of easily removable access panels or sections provided in sufficient quantities so that power and signal cables,


© Mobil Oil, 1997 72 of 80

wiring and all space beneath the raised flooring or decking are accessible in emergencies. Tools required for lifting panels shall be provided in the computer area.

3. Joints around floor panels or sections and openings in the flooring or decking for cables, wiring or other uses shall be protected to minimize the entrance of debris or other combustibles beneath the flooring or decking.

Cable and wire openings shall be made smooth or shall otherwise be protected to preclude the possibility of damage to the cables or wiring.

4. Fascia or closure plates, which form sidewalls for ramps or edges of the flooring system, and handrails shall be of noncombustible materials.

5. When a raised floor system is to be installed in an area having combustible finish flooring or floor covering, insulating noncombustible materials shall be installed over the flooring or floor covering.

6. A structural floor on which a computer system is located, or which supports a raised floor installation, shall incorporate provisions for drainage of the floor surface to minimize damage to the system and associated wiring due to domestic water leakage, sprinkler operation, coolant leakage or fire fighting operations. Backwater valves shall be provided if there is any danger of water backing up through the drainage system. Drainage system connections to an oily water drainage system are prohibited.

17.3.4. Air Plenums When the air space below a raised floor or above a suspended ceiling is used as a supply or return for air conditioning, the construction shall be noncombustible, and all wiring shall be listed or certified for the application by an independent testing laboratory such as Underwriters Laboratories Inc. or Factory Mutual.

17.3.5. Fire Stops Noncombustible fire stops equivalent to 24 gauge galvanized sheet metal shall be installed in the concealed spaces formed by a raised floor and floor below, or by a ceiling and floor or roof above. The space shall be subdivided into compartments not exceeding 930 m2 (10,000 ft2) in area or 30 m (100 ft) in any direction.

17.3.6. Ceilings

Ceilings shall be provided with access doors, panels, hatches or other means of ready access to all portions of the concealed space. In fire-resistive ceilings, access panels shall be of construction equivalent in fire resistance to the ceiling rating.


© Mobil Oil, 1997 73 of 80

17.4. General Computer Area Requirements

17.4.1. General Except as noted herein, only the actual computer equipment and the auxiliary equipment electronically interconnected with it, or that must be located in close proximity to it, shall be permitted in the computer area.

17.4.2. Records Storage Record storage in the computer room shall be limited to the absolute minimum required for efficient operation.

17.5. Machines and Cables

17.5.1. Computer Equipment Each individual unit shall be constructed so that by limiting combustible materials, or by use of enclosures, fire is not likely to spread beyond the unit in which the source of ignition is located. Enclosures of floor-standing equipment having external surface of combustible materials of such size that might contribute to the spread of an external fire shall have a flame spread rating of 50 or less (see NFPA 255). Automatic fire protection shall be provided for all units not so constructed.

17.5.2. Cables Interconnecting cables and wiring between units, power cords, plugs and connectors shall be of a type listed by an independent testing laboratory, such as FM or UL, for that specific installation. They shall be considered part of the computer system and suitable for installation on the floor or under a raised floor. Where supported by racks, trays or other devices, the entire support system shall be of noncombustible construction. Flexible cord and plug assemblies used for connecting computer equipment to the branch circuit to facilitate interchange shall not exceed 4.5 m (15 ft) in length.

17.6. Fire Protection Systems

17.6.1. Automatic Sprinkler Systems An automatic sprinkler system shall be provided when:

• Computer equipment is housed in a structure or room built of combustible material

• Computer rooms contain a significant quantity of combustible material


© Mobil Oil, 1997 74 of 80

When the computer is left unattended and energized, the computer room shall be protected by automatic fire detection and sprinkler (pre-action) systems. Alarms shall be transmitted to a constantly attended location.

17.7. Utilities

17.7.1. Air Conditioning Systems Heating, ventilation and air conditioning equipment shall conform to the requirements of NFPA 90A. All duct insulation and linings shall be noncombustible, including vapor barriers and coating. Air filters for use in air conditioning systems shall be of approved types that will not burn freely or emit a large volume of smoke or other objectionable products of combustion when attacked by flames. They shall be arranged so that they can be readily inspected, cleaned and/or replaced when necessary.

17.7.2. Electrical Service All wiring and associated equipment shall conform to NFPA 70. Service transformers required to be located in the electronic computer area shall be of the dry type. Protection against lightning surges shall be provided where needed. Junction boxes in underfloor areas shall be metal, securely fastened to the floor, completely enclosed, easily accessible and properly grounded. No splices or connections shall be made in the underfloor area except within junction boxes or approved types of receptacles or connectors. An emergency lighting system shall be provided meeting the requirements of NFPA 101.

17.7.3. Emergency Power Controls In addition to any integral individual disconnect switches for components for other units of the data processing system, a disconnecting means shall be provided as part of the main service wiring. The disconnect shall be controlled from locations readily accessible to the operator's control panel and to the principal exit doors. It shall disconnect all the power to electronic equipment and to the heating, ventilation and air conditioning system. It shall be suitably marked and protected against inadvertent actuation.

17.7.4. Coolant Systems If a separate coolant system is required for operation of a computer installation, it shall be provided with a suitable alarm, to indicate inadvertent loss of fluid, arranged to sound in a continuously manned location.

17.7.5. Emergency Controls All utility systems required for continuous operation of a computer area will have, in an accessible location, complete schematics and operating


© Mobil Oil, 1997 75 of 80

instructions for emergency operations. Valves, operating switches, control devices and similar critical equipment will be prominently identified on the schematics and will be similarly physically identified to aid in use during an emergency.

18. Piers and Wharves

18.1. Pier and Wharf Construction

Construct petroleum piers and wharves of noncombustible construction unless unusual structural or local circumstances require the use of wood piling. In all cases, except for small piers or barge docks, the deck shall be of concrete or other noncombustible construction. Accessways vital to escape for fire fighting shall always be noncombustible and without openings. Pier deck areas not used for access or escape purposes may have a limited amount of subway grating or open construction.

Coatings or vapor shields and barriers underneath the pier shall meet flame-spread requirements specified in NFPA 307.

Fire protection for piers and wharves shall also meet the requirements of NFPA 58. LPG loading and unloading facilities on piers and wharves shall also meet the requirements of NFPA 58. LPG loading and unloading facilities on piers and wharves shall reflect the appropriate guidance of API STD 2510 and API PUB 2510A.

18.2. Fire Stops and Spill Containment

Measures shall be taken to prevent fire spread beneath combustible pier construction and product spills from exposing the entire pier or wharf. These measures shall include:

1. Fire Stops: On minimum of 45 m (150 ft) centers, of noncombustible construction extending to the low water level where tide, wind exposure, current and ice conditions permit

2. Draft Curtains: Used under combustible pier deck construction spaced in accordance with NFPA 307

3. Spill Containment: Booms or fire stops

The pier shall be designed to prevent trapping of vapor and spilled product beneath it when a tanker is moved to the structure.


© Mobil Oil, 1997 76 of 80

18.3. Fire Protection

18.3.1. General Minimum fire protection requirements for various size installations shall be in accordance with Table 7.

Table 7: Fire Protection Requirements for Petroleum Piers and Wharves*

Installation Requirements (Minimum)

Barge pier or wharf for transfer of Class I products, or any product heated above its flash point, and Class I products in drums

Fire main and hydrants with firewater supply of at least 340 m3/h (1500 gpm)

Portable fire protection including monitors and portable fire extinguishers

No foam, provided foam is available from onshore equipment

Barge pier or wharf for transfer of Class II products or any product, except Class I products, in drums

Portable fire protection consisting of hand and wheeled fire extinguishers

Tanker pier or wharf for transfer of product. Tanker size less than 20,000 DWT and fewer than 60 ships handled per year

Portable fire protection consisting of hand and wheeled fire extinguishers

One international connection if a water main is available

Tanker pier or wharf for transfer of product. Tanker size less than 50,000 DWT. Good access to facility

Fire main and hydrants with firewater supply of 340 m3/h (1500 gpm)

Portable protection including monitors, foam protection and backup available from shore equipment and fire boat

Tanker pier or wharf for transfer of products or offloading crude. Tankers 50,000 DWT or larger. Good access to facility


Fixed fire protection equipment (See Section 5.7). Below deck foam/water sprinklers. Portable fire extinguishers

Tanker pier or wharf for transfer of products or offloading crude. Tankers 50,000 DWT or larger. Poor access from shore


Fixed fire protection equipment (see Section 5.7). Below deck foam/water sprinklers. Portable fire extinguishers

Backup by fire boats. Portable fire extinguishers

Tanker pier or wharf for loading crude Fire main and hydrants with firewater supply of 900 m3/h (4000 gpm)


© Mobil Oil, 1997 77 of 80

Installation Requirements (Minimum)

Fixed fire protection equipment (see Section 5.7). Below deck foam/water sprinklers

Backup by fire boats with foam and shore-based fire trucks. Portable fire extinguishers

Tanker pier or wharf. Limited shore facility. No serious neighboring exposures. Tankers less than 50,000 DWT and barges

Fire main and hydrants or fixed dry chemical and aqueous film forming foam (AFFF) system, or both

Portable dry chemical equipment

At least one fire boat with foam available. Portable fire extinguishers

Island tanker pier Fire main and hydrants with firewater supply of 680 m3/h (3000 gpm)

Fixed fire protection equipment (see Section 5.7)

Fire boats available for backup. Portable fire extinguishers

Sea berth, single -buoy mooring or spread mooring

For floating product or crude handling facilities 340 m3/h (1500 gpm) supply of firewater

At least two boats with water and foam available

18.4. Fire Boats

Generally, one or more fire boats are needed to fight an extensive fire on a pier or wharf.

• It is usually impossible to provide foam or cooling streams on a large tanker from only the pier or wharf.

• Depending on wind direction and extent of a spill fire, the pier or wharf may become impossible to approach so that preliminary fire fighting and fire control may have to be accomplished by fire boats.

• The availability of municipal fire boats shall be determined and the elapsed time for response shall be known.

Such factors can have an effect on determining the amount of fire fighting equipment needed for the pier, as well as the possible need for a private fire boat.

When municipal fire boats are not readily available, tugs can be equipped for fire fighting or specially fitted fire boats provided. A fire boat for fighting petroleum fires shall be equipped with at least a 115 m3/h (500 US gpm) monitor plus 170 m3/h (750 gpm) for hose streams. A separate engine drive is needed for the fire pump so that the propulsion engine can maintain the boat's position during fire fighting.


© Mobil Oil, 1997 78 of 80

18.5. Alarms and Communications

A manual fire alarm station and audible alarm on the pier, connected to the plant or refinery fire alarm, shall be installed. The alarm system shall be fully compatible with and integrated into the shore facility alarm system and can be used to signal emergency shutdown of shore pumps.

19. Truck Loading Rack Protection

19.1. Design Basis

Tank truck loading facilities shall be designed to meet the requirements of EPT 15-T-10. Electrical and control systems, including bonding and grounding, emergency shutdowns and interlocks shall be provided in accordance with EPT 15-T-18a and EPT 15-T-18b.

• A drainage system, designed in accordance with EPT 15-T-01, EPT 15-T-10, EPT 15-T-18a and EPT 15-T-18b, shall be provided to permit such spills to be flushed and drained away from the rack to a safe location without entering a public sewer system.

• Foam may be used at flammable liquid loading racks to blanket large spills and to prevent ignition until cleanup can be accomplished.

• Prevention of electrostatic ignitions is covered in detail in API RP 2003. Bonding of the fill system to the truck is necessary to ensure that equipment is at the same electrical potential to prevent sparking.

19.2. Fire Extinguishers

19.2.1. Company Attended Racks For protection of flammable liquid racks that are attended by company personnel during loading operations, each rack island shall be provided with at least one 9 kg or 13.6 kg (20 lb or 30 lb) BC type dry chemical hand fire extinguisher, or the equivalent.

The extinguisher shall be installed on the fill platform within easy reach or at grade. In addition, one 150 kg (350 lb) BC type dry chemical wheeled extinguisher with 30 m (100 ft) of hose or one 150 kg (350 lb) trailer-mounted extinguisher shall be available for each rack containing up to four bays. One additional wheeled extinguisher shall be available for each additional four bays or fraction thereof.

At least one 38 mm (11/2 in) hose, equipped with a foam nozzle and of sufficient length to reach all portions of the rack, shall be provided. A self-


© Mobil Oil, 1997 79 of 80

contained foam system or an aqueous film forming foam (AFFF) dry chemical system shall be considered if water is not available.

19.2.2. Driver Attended Racks Protection for driver-attended racks shall consist of one 9 kg or 13.6 kg (20 lb or 30 lb) dry chemical extinguisher, or the equivalent, on each rack island.

19.3. Shutdown Systems

An emergency shutdown system for pumps and product shutoff valves, designed in accordance with EPT 15-T-18a and EPT 15-T-18b, shall be provided in all product lines to the rack area so that the fuel source can be shut off in the event of fire.

• These valves shall be located in a remote area and be at least 15 m (50 ft) from the nearest truck loading position if they are hand-operated.

• Power-operated valves, which can be closed by emergency shutdown switches at the rack loading position and at the office and by a fire detection device, may also be used for this purpose.

• Automatic and fixed manual fire protection systems shall be interlocked to shut down product flow.

19.4. Fixed Fire Protection Systems

19.4.1. Application A fixed foam fire protection system shall be installed on loading racks when any of the following conditions apply:

1. New or renovated top-loading racks where Class I products are loaded or where switch loading is practiced

2. New racks where only the driver may be in attendance and where Class I and Class II products are open-top loaded

3. New or renovated racks where only the driver may be in attendance and where Class I products are bottom loaded

4. New or renovated bottom-loading racks where switch loading is practiced

19.4.2. Design A fixed foam extinguishing system shall be installed where required by the previous Section.


© Mobil Oil, 1997 80 of 80

• The fixed foam system shall be designed to provide a density of 6.5 (L/min)/m2 (0.16 US gpm/ft2) of a suitable aspirated foam over the full surface being protected.

• Application shall continue for a minimum of 10 minutes. A 20-minute minimum supply of water and foam concentrate shall be available when there are firewater limitations.

• A self-contained nitrogen pressurized fixed foam system, with water and foam concentrate stored in sufficient quantity in tanks situated in a safe location near the rack, is acceptable in locations with limited water supply.

• System design shall be in accordance with NFPA 11.

• The area subject to the spill shall be provided with a spill-control system, including drainage with fire stops and high grading or curbs to contain the spread of spilled hydrocarbons within the protected area.

If no water supply is available, a dry chemical fire protection system shall be provided.

mp70p01

Documents