Structure Fire Flashcards
What can be achieved by manipulating the fire triangle?
More effective control and extinguishment of structural fires
What is Pyrolysis?
The decomposition of a substance caused by heat
What is latent heat of vaporisation?
The amount of heat required to change a given mass of substance from liquid to a vapour
What is heat release rate?
Amount of heat energy released over time
What is a flash point?
The lowest point a substance produces flammable vapour
What is a flame point?
The lowest temperature at which a substance produces a vapour that can sustain a continuous flame
What is auto ignition temperature?
Temperature at which fuel will ignite on its own
What is the neutral plane?
The area between the under pressure (fresh air) and over pressure ( hot fire gasses)
Why does a gravity current occur?
Because fresh air is denser than hot gases existing within the compartment
What is Thorntons rule?
Each KG of O2 used in combustion results in the release of 13.1MJ of energy.
More 02 increase heat release rate
What is Charles law?
The volume of a fixed mass of gas at constant pressure is directly proportional to its absolute temperature.
Gasses expand when heated
Gasses become less dense and will rise
What is Gay Lussacs law?
The volume of a gas remains the same and temperature is increased, pressure increases in proportion to the absolute temperature of the gas.
When gasses are confined and heated, pressure increases
Increased pressure indicates higher temperatures
What is a fuel controlled fire?
A fire that has ample oxygen but not adequate fuel
What is a ventilation controlled fire?
A fire that has adequate fuel, but not enough air
What are the four stages of a fire?
Developing
Flash over
Fully developed
Decay
What are the signs of flashover?
Ventilation controlled, vented fire
Painful radiant heat
Low turbulent neutral plane
Fingers of flame through smoke
Hot surfaces
Increased rate of pyrolysis
Increased turbulence of the neutral plane
Signs of a backdraught?
Ventilation controlled, non vented fire
Lack of visibility
Dirty smoke
Smoke pulsating through small gaps and openings
Air being drawn in
Indicators of extreme heat ( Blistering paintwork, crazing glass)
What is a fire gas explosion?
An event that occurs in a seperate compartment from Origin fire.
Signs of a fuel controlled fire?
Developing fire
High neutral plane
Better visibility
Bright yellow flame
Fire in decay stage
Signs of a ventilation controlled fire?
Fully developed fire
Low neutral plane
Poor visibility
Air being drawn back into fire
Smouldering fire
Smoke pulsating out of openings
Whistling sound
What is the purpose of a direct attack?
To extinguish the fire by directly cooling burning material using jet
What is the aim of exterior water application?
To support interior operations by applying water onto fire asap
What is the purpose of an indirect attack?
To extinguish fire by generating large volumes of steam. Usually used when fire is fully involved to suppress a potential backdraught risk
What is gas cooling?
Gas cooling techniques are used to control the fire environment while firefighters advance during fire attack.
By cooling gases below their auto ignition temps firefighters can prevent further fire spread and potential for flashover
What is the key to effective water use?
To place water where it is most needed. In the hot fire gases and on burning combustibles
A fire attack crew should never ignore a?
Victim
A search and rescue crew should never ignore a?
Fire
What floors should be prioritised during search and rescue in a high rise?
Fire floor
Floor above fire floor
Top floor
Signs of blow torch effect?
Pulsing smoke
Working fire
Ventilation controlled vented fire
Noticeable winds
What is salvage?
Actions taken during and immediately after the fire to minimise damage caused by fire and the water used to extinguish it
Signs of impending collapse?
Falling plaster, mortar, bricks or from walls or ceilings
Cancerous concrete spalling
Walls leaning or bulging
Ceilings sagging
Floors spongy or springy
Gaps appearing in between walls, beams or ceilings or walls and floors
Cracked or sagging arches over door or window openings
Displacement of supporting pillars, joists or beams
What is overhaul?
The systematic checking, turning over and wetting down of structural materials and contents to ensure that no pockets of fire still exist
Class A fires
Ordinary combustibles ed wood’s plastics paper etc
Class B fires?
Flammable and combustible liquids
Class C fires?
Flammable gases
What fires do you use water extinguishers on?
Class A
What class fires do you use a foam extinguisher on?
Class B
What fires do you use dry chemical on?
A,B,E
What class fire would you use wet chem on?
Class F
Why do you ventilate?
To remove heat and gases and introduce fresh air after fire control has been established
