Flashcards in PN793 Compartment firefighting Deck (28)
What might happen in a compartment fire that is
un-vented and oxygen starved, when the compartment is ventilated by a BA team?
The resulting deflagration (explosion) will expand following the ventilation pathway to open-air.
What can build up and collect in areas of a building with there presence not being obvious during a fire?
Explosive atmospheres and fire gases.
(If these are in the correct concentration and when exposed to a source of ignition these can ignite causing an explosion even after the primary fire has been extinguished.)
What should a firefighting jet compromise of when entering a compartment?
45mm hose-line with branch set at 230lpm.
What is the principal purpose of the second firefighting jet?
To protect access and egress from a compartment.
A second fire fighting jet should be provided as soon as possible what is its makeup?
45mm hose-line, branch set at 230lpm and at least one length longer than the firefighting jet.
In a compartment that is adequately ventilated a sudden and sustain transition of a growing fire to a fully developed fire is known as what?
What will the application of water within a fire compartment produce if the fire compartment is over 100°C?
What is the purpose of a covering jet?
It should be used outside of the compartment to extinguish flame, un-burnt products of combustion and protect surrounding risks.
What should covering jets not be used for?
They should not be used to spray directly into openings.
(This can push flames and products of combustion back into the compartment also inducing a quantity of fresh air. This can increase fire intensity.)
What should the IC conduct prior to any compartment fire-fighting?
A 360° survey.
What is the 360° survey looking for?
Possible life risk.
Extent of fire.
Potential ventilation outlets.
Who should the IC consult with before making a decision that affects the operation of a fixed installation or building system?
’Responsible person’ or Fire Safety Officer (FSO)
What other sources of information should be investigated before compartment firefighting commences?
Automatic fire alarm panels
Building occupiers or building signage.
(Information such as access, layout, water suppliers and options for tactical or mechanical ventilation.)
What should BA teams be briefed on before being committed?
Number and locations of any persons reported.
Location and extent of fire.
Nature of occupancy.
The route and task involved to gain access to compartment.
What should happen to hose lines before teams are sent to commence firefighting?
Hose lines must be charged, branches and watersupply checked by opening for several seconds and checking branch flow and jet patterns.
What should be formed comprising the same number of personnel as the largest BA team committed?
BA emergency team.
If a compartment fire is showing signs of backdraught, flashover or fire gas explosion what firefighting techniques should be adopted?
If the signs of backdraught are present what can you do to a compartment before sending in a BA team?
Ventilate the compartment.
What needs to be in place before external ventilation is carried out?
A covering jet.
What is a good tool to identify the seat of a fire?
Thermal image camera.
Where possible BA teams should ensure that all access route doors are closed behind them once they have withdrawn why?
To isolate the flow path’s and contain the fire.
Why should BA teams remain as low as practicable?
To take advantage of the cooler air directly above floor level.
What should a BA team do if they experience a loss of water at any stage during compartment firefighting?
What impact would forcing entry into a compartment have?
Once the integrity of the door or opening is lost it may not be possible to contain the fire.
What are the objectives of compartment firefighting?
Maintain firefighter safety.
When can ventilation of a compartment take place?
Only on the direction of the IC.
In unvented compartments precooling of gases is essential where?
Outside the fire compartment.