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Additional Hazard or Information Sheet
Flammable Liquids
Document Overview
Initial information to both inform and assist Incident Commanders when
dealing with this subject matter:
Incidents involving flammable liquids.
1
Hazards

Explosion – Vapours may form explosive mixtures with air. The explosive hazard is
enhanced in confined spaces.

Flammable vapour – Vapour production is increased when substance is heated or
surface area is increased. Most vapours are heavier than air and will spread along
ground and collect in low or confined spaces e.g. cellar basements and sewers. Any
ignition sources present will provide a flashback.
o
The majority of flammable liquids do not mix with water and are lighter than
water and will therefore “float” on the surface. This will generate more vapour
which may be flammable.

Boiling Liquid Expanding Vapour Explosion (BLEVE) – Half full or empty
containers are more dangerous than full ones as pressure space is greater.

Mixture of substances leading to auto-ignition and fire growth– Some
flammable liquids, e.g. alcohols will react violently with acids and alkalis, generating
large amount of heat and pressure build-up. Oxidising agents will also generate large
amount of heat if mixed with a flammable liquid.

Toxic/corrosive – Inhalation or contact with material may irritate or burn skin and
eyes. Any vapours may be toxic and/or corrosive and may cause dizziness or
suffocation.

Environmental impact - The chemical structure of flammable liquids are severely
damaging to the environment. Substances on their own or part of the fire water run
off should be contained if at all possible.

Running fuel fire – Ignition of uncontained flowing liquids leading to rapid fire
spread/development.
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Flammable Liquids
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Actions
Generic actions



Consider gas monitoring to determine the extent of the vapour hazard/explosive
atmosphere
Cordons:
Initial cordon 50m
Large spill (more than 200ltrs) 300m
Fire in tank on road or rail 800m
Consider appropriate PPE/RPE/decontamination
Un-ignited leak of flammable liquid

Once the substance(s) physical properties and environmental impact have been
identified, the following actions should be considered:
o
Eliminate all ignition sources
o
Stop leak if practicable
o
Prevent substance entering water courses, drainage systems, basements, etc
o
Absorb substance with sand, earth or other non-combustible materials
o
Consider foam suppression of vapours
o
Consider using water spray to control vapours
o
Consider water cooling of container/ tank to reduce vapour release
o
Use intrinsically safe equipment
Substance involved in fire

3
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
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Usually easier to deal with but more hazardous:
o
Use CO2 or dry powder for small fires
o
Do not directly apply water to burning flammable liquid as this may lead to
violent reaction, boil-over or slop-over
o
Consider using foam, alcohol resistant foam or water spray on large fires
o
Cool any affected containers with water spray. Tanks or containers involved in
fire may over pressurise and explode (BLEVE)
Further considerations
Beware of flammable liquids entering drains, sewers and other low lying spaces
where it may vaporise and create an explosive atmosphere
Block drains and contain substance if possible
Provide good ventilation to avoid vapour build up
Reduce the surface area if possible:
o
Use of plastic salvage sheet
o
Foam blanket
o
Containment
Prevent oil substances from contaminating PPE due to fire risk. Use disposable
gloves/general purpose gauntlets.
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
Supporting information
Some drainage plans have pollution control devices such as penstocks. With
permission and planning, such devices can be used by FRSs to prevent pollution to
surface and groundwater and to protect sewage treatment works.
 Flammable liquid hazard warning diamond is shown on the right
 UN class and ADR Hazard Identification Number (HIN): 3
 Described as:
1. Flammable.
2. Highly Flammable.
3. Extremely Flammable.
Boiling Liquid Expanding Vapour Explosion (BLEVE)
When a container is subjected to heat, especially when heating is due to direct flame
contact, expect a BLEVE at any time if adequate cooling is not available.
 When containers are heated, without adequate cooling, a BLEVE could occur.
 This is usually a result of the heating of a vessel containing a liquid by an external fire.
 The contents of the vessel are heated above their boiling point and the pressure in the
vessel increases.
 The failure occurs when the flames impinge on an area which does not have liquid on
the other side (dry wall).
 The vessel ruptures and pieces can be propelled considerable distances.
 The spillage of the overheated liquids and then ignition create a large fireball with
explosion pressure effects. This can mean that it is extremely difficult to predict when,
and if, a BLEVE will occur.
 A vessel that is venting in a fire does not mean that everything is safe, more than
likely the opposite is the case. A BLEVE can occur at any time and some have occurred
many hours into an incident.
 Reduction of tank contents may hasten the onset of a BLEVE due to the increase in dry
wall area as the tank is emptied.
 Remember that in the event of a BLEVE the fireball can engulf exposed crew.
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Flammable Liquids
Document References
1.
Relevant References
This incident type is potentially linked to the following other operational guidance
documents:
Document Name
Link to Document
To be populated
2.
Technical References


CFRA Fire and Rescue Service Operational Guidance Hazmat Incidents – Part B –
Section 7.
Emergency Response Guide 2012.
Ref no:
Date of issue:
Version no:
Page 4 of 4
H3.0.0
07/10/2014
1
Lead FRS:
Review date:
Protective
marking:
NOT PROTECTIVELY MARKED
Hampshire
07/10/2017
None