Structural Fire Fighting Flashcards
What can manipulating the fire triangle help FF’s do?
Effectively control and extinguish structural fire.
What is Pyrolysis?
Pyrolysis is 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 a liquid to a vapour.
What is Heat Release Rate?
The amount of heat energy released over time.
What is flashpoint?
Flash point is the lowest temperature at which a substance produces flammable vapour.
What is fire point?
The lowest temperature at which a substance produces a vapour that can sustain a continuous flame. Usually a few degrees above the flash point.
What is auto ignition temperature?
It is the temperature at which fuel will ignite on its own without any additional source of ignition.
What is the flammability range?
The flammability range is the ratio of fuel to air.
What is the neutral plane for structural firefighting purposes?
The area between the under pressure (fresh air) and the over pressure (hot fire gasses) in a compartment.
Why does a gravity current occur?
Because fresh air is denser than the hot gases existing within the compartment.
Explain Thorntons rule in simple terms.
As fire accesses more Oxygen, or as the oxygen increases, the heat release rate increases leading to potentially increased rates of extreme fire behaviour.
Why is it important to understand Gas laws?
Can help a FF assess the stages of fire progression and intensity.
Define a fuel controlled fire.
A fire that has more than enough air for combustion.
Define a ventilation controlled fire.
A fire, where its growth is limited by the available air supply.
What are the four phases of fire progression?
Developing fire
Flashover
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
What are the signs of backdraught?
Ventilation controlled, non-vented fire
Lack of visible flame
Dirty smoke
Smoke pulsating
Air being drawn in
Indicators of extreme heat
What is the difference between a fire gas explosion and a backdraught or flashover?
Fire gas explosion occurs in a seperate compartment from the fire room where’s the other two occur within the fire room itself.
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
Whistling sounds
What is the purpose of direct attack?
To extinguish fire by direct surface cooling of the burning combustibles using a jet or spray.
Purpose of an indirect attack.
Extinguish a fire by creating large amount of steam. Joint effect of gas and surface cooling and excluding oxygen from the compartment.
What are gas cooling techniques used for?
To control the fire environment while FF’s advance during fire attack or perform search and rescue.
What is the key to effective water use?
To place water where it is most needed, in hot fire gases and on burning combustibles
When would you use an indirect attack?
When fire is fully involved or to suppress suspected backdraught
What does Charles Law establish?
Gases expand when heated
Gases become less dense and rise when heated
What does Gay-Lussac’s Law establish?
When gases are confined and heated, pressure increases.
Increased pressure indicates higher temperatures.
