Day 3 Flashcards
Fire Science
Define combustion
The chemical reaction in which fuel combines with oxygen
What are the 3 parts that make up the triangle if combustion
Oxygen
Heat
Fuel
Define pyrolysis
Thermal decomposition of a substance by heat
Define a passive
Something that absorbs heat from a fire
Explain the limit of flammability
A flammable gas will only burn in air if it’s composition lies between certain limits.
If the mixture is too lean or too rich burning will not take place
Explain the limit of flammability
A flammable gas will only burn in air if it’s composition lies between certain limits.
If the mixture is too lean or too rich burning will not take place
Define the lower limit if flammability
The lowest possible concentration of fuel that will just support a self propagating flame
Define the upper limit of flammability
The highest concentration of fuel that will just support a self propagating flame
Define ideal mixture
When the concentration of gas us is exactly right in relation to the amount of oxygen in the air for combustion to occur with maximum force
What effects fire development?
Position of fire
Ceiling height
Smoke layer
Ventilation
What are the phases of a fire?
Early
Growth
Fully developed
Decay
What are the 3 methods of gas cooling?
Short pulse
Cooling gases above BA team, creates a safety zone and protects the exit route
Long pulse
Absorbs energy and fighting fire back
Coning down - at pockets if ignited fire gases
Absorbs energy
