What are the two pressure regions inside a compartment fire and what separates them?
Separated by the neutral plane.
What is Pyrolosis?
Decompostion of a substance by heat.
What are two types of 'controlled fire?
Flashover is a transition stage in the development of a compartment fire that results from the ignition of accumulated fire gases leading to total room involvement.
Once it has consumed the available oxygen, the fire begins to subside, even though the compartment and the contents are still very hot.
The introduction of oxygen supplies the missing ingredient and the smoke ignites, if an ignition source is available.
What signs do firefighters need to be alert for when reading a fire?
Height & movement of neutral plane.
Changes in the air track.
Changes in smoke colour.
Pulsations of smoke.
Turbulent movement of smoke gases.
Smoke being drawn back through an opening.
Flames in the overpressure region.
Blackening and crazing of windows without flame showing.
Colour of flame.
Heat build up.
What are three methods of extinguishing a fire?
What is ventilation?
Ventilation is the planned and systematic removal of smoke, heated air and fire gases from a structure and their replacement with a supply of cooler and cleaner air in order to faciliitate other firefighting priorities.
What are the advantages of ventilation?
Speeds initial attack by improving visibility allowing for quicker location of and access to the seat of the fire.
Removal of superheated gasses reduces flashover/backdraught risk.
Working conditions will be improved.
Speed of secondary searches increased.
Victim survival increases due to removal of toxic gases and introduction of clean air.
Property damage lessened by quicker extinguishment.
Overhaul conditions are improved with the removal of toxic gases.
What will the IC consider before commencing ventilation?
Location of fire.
Best location for the exhaust opening to be created (use of TIC).
Appointment of FF to coordinate ventilation operations.
Informing fireground personnel that PPV is in operation and location of exhaust vents.
Once PPV has commenced, entry to structure will be by inlet opening only.