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Flashcards in Fire Science Deck (14)
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1
Q

What is the definition of combustion?

A

The chemical reaction in which fuel combines with heat and oxygen

2
Q

What is the definition of pyrolysis?

A

The thermal decomposition golf a substance by heat.

3
Q

What is the process of pyrolysis!

A

Thermal capacity is reached.
Gases given off.
Gasses ignite.

4
Q

What is a passive agent?

A

Something that absorbs heat from fire

5
Q

3 characteristics of passives?

A

Already present or produced in combustion process.
They take no part in the chemical reaction.
Passives absorbing heat will have an effect on the fires behaviour.

6
Q

2 types of fire gases and examples?

A

Non flammable gases-co2, water vapour.

Flammable gases- due to incomplete combustion. Includes carbon monoxide

7
Q

Between what 2 limits will fire gases burn?

A

Too lean -LEL, lower explosive limit.

Too rich-UEL, upper explosive limit

8
Q

The exact conditions for oxygen in the air for combustion with maximum force is known as what?

A

The Ideal mixture

9
Q

Factors that effect fire development?

A

Position of fire-4,2,1 rule.
Ceiling height
Smoke layer ( over pressure, under pressure).
Ventilation

10
Q

4 phases of fire?

A

Early phase
Growth phase
Fully developed phase
Decay phase

11
Q

3 extinguishment methods?

A

Direct
Indirect
Gas Cooling

12
Q

What is the direct cooling technique?

A

Narrow jet aimed directly at seat of fire.

Painting is a more controlled version of this.

13
Q

What is indirect cooling?

A

A spray aimed at the fire gases and hot compartment boy fires.
Can be used outside the compartment to cool and dilute fire gases.

14
Q

3 methods of gas cooling?

A

Short pulse-above BA team
Long pulse -forward into fire gases
Coning down -pockets of ignited flames