The document provides guidance on conducting a fire hazard analysis (FHA). An FHA identifies fire hazards, determines the potential severity and duration of fire scenarios, and estimates their impact. It involves developing an inventory of flammable and combustible materials, defining potential fire scenarios based on losses of containment, calculating the size of fires, and analyzing the impact of fire outputs like smoke, flame and heat on personnel, structures, equipment and the environment. The analysis helps specify appropriate fire protection and mitigation measures by providing an understanding of the fire risks.
3. Introduction
• Fire hazard analysis (FHA) is the process to
determine the size, severity, and duration of a
scenario and its impact on personnel, equipment,
operations, and the environment
• A fire hazard analysis (FHA) is a tool/method used
to understand fire hazards
• Scope of this Section:
– Guidance on how to develop different types of fire
scenarios common to process facilities.
– Steps and tools for conducting an FHA.
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4. FHA Objectives
• Provides an understanding of the hazards
• Enables the specification of performance-
based fire protection
• Forms part of an overall risk assessment
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7. Benefits
• An inventory of fire hazards, including quantities.
• A comprehensive understanding of the fire
hazard, including potential magnitude and
duration.
• An estimate of the potential impact of a fire on
personnel, equipment, the community, and the
environment.
• Development of a list of appropriate mitigation
options.
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8. Hazardous Chemicals and Processes
• Chemical, petrochemical, and hydrocarbon
industry processes involve the handling of a vast
number of flammable and combustible materials
• Types of Fires:
– Jet fire
– Flash fire
– Pool fire
– Running liquid fire
– Boiling liquid expanding vapor explosion (BLEVE) or
fireball
– Vapor cloud explosions
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9. Outcome of gas leak
Gas leak
No ignition
Vapour cloud
Radiation
Flame emersion
Turbulent
Vapor cloud
explosion
Flash fire
Jet Fire
Delayed
Immediate
Ignition
Toxic cloud
EVENT
HAZARD
Pressure missiles
radiation 9
10. Outcome of liquid leak
Liquid leak
No ignition
Vapor cloud
Liquid Pool
Radiation
Flame emersion
Fire spread by flowing liquid
Turbulent
Vapor cloud
explosion
Flash fire
Jet Fire
Pool Fire
Delayed
Immediate
Ignition
Toxic cloud
Toxic pool
EVENT
HAZARD
Pressure missiles
radiation
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11. 1 Recognize what you want to
understand
• FHA provides information on:
– Understanding the fire hazards and determining how they
should be controlled.
– Determining if personnel have time to escape the building
or facility.
– Determining the potential damage to structure and
equipment.
– Determining the level and extent of passive fire protection
which may be required.
– Defining the active protection systems needed to
limit/control fire spread.
– Determining fire water demand and duration of worst-
case fire scenarios.
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12. 2 Identification of Inventories
• An inventory of flammable and combustible
materials should be developed for each
process unit and storage area within a facility
• This list should contain the quantity, storage
configuration, material characteristics, and
location
• The inventory list should be maintained
throughout the lifecycle of the facility by the
Management of Change (MOC) process
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13. 3 Define Fire Scenarios
• Fires range in size and consequence from those that
are small, easily controlled, and result in minor damage
to those that are large, difficult to control, and create a
major loss.
• Fires in process facilities usually follow a loss of
containment
• Fire Consequences depend on:
– weather,
– Wind
– leak orientation
– Rate at which the spill occurs
– Total amount spilled
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15. 4 Calculate Potential Fires
• Fire hazard calculation techniques for
combustible and flammable liquids and gases
range from the basic to the sophisticated,
including computer modeling techniques
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17. 5 Fire Impact
• Fires produce four major outputs:
– gases,
– flame,
– heat,
– Smoke
• consequences to personnel, structures, and
equipment
• Consequences Analysis
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18. Impact to Personnel
• Thermal Radiation
– Burns to exposed skin.
– Ignition or melting of clothing
• Burns are classified in increasing degrees of severity:
– First degree—superficial burns giving a red, dry skin
(similar to mild sunburn).
– Second degree—burns more than 0.1 mm deep, affecting
the epidermis and forming blisters.
– Third degree—burns more than 2 mm deep, affecting the
dermis and nerve endings, resulting in a dry skin that has
no feeling (major blistering).
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19. Skin damage
• Skin damage begins at about 45°C (113°F) and
becomes virtually instantaneous at 72°C
(162°F)
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23. Impact to Structures
• Steel, aluminum, concrete, and other
materials that form part of a process or
building frame are subject to structural failure
when exposed to fire
• A structural member undergoes any
combination of three basic types of stress:
compression, tension, and shear
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24. Temperature and Materials
• Paint begins to soften 204°C (400°F)
• Zinc primer paint discolors to tan 232°C (450°F)
• Zinc primer discolors to brown 260°C (500°F)
• Normal paints discolor 310°C (600°F)
• Zinc primer paint scorches to black 371°C (700°F)
• Lube oil autoignites 421°C (790°F)
• Stainless steel begins to discolor 427-482°C (800-900°F)
• Plywood autoignites 482°C (900°F)
• Vinyl coating on wire autoignites 482°C (900°F)
• Rubber hoses autoignite 510°C (950°F)
• Aluminum alloys melt 610–660°C (1,125–1,215°F)
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28. Thermal and Nonthermal Impact on Electrical
and Electronic Equipment
• A heat flux of 25 kW/m2 has been published as a
general rule-of-thumb for damage to process
equipment
• thermal impact of fire on electrical and electronic
equipment:
– 50°C (122°F) for faults in operating electronic
equipment.
– 150°C (302°F) for permanent damage to
nonoperating equipment.
– 250°C (482°F) for failure of standard Polyvinyl
Chloride (PVC) cable.
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