Fires

Backdraft

An explosive reignition that can occur when oxygen suddenly enters a smoldering, oxygen-starved fire area.

Chemical Reaction (in fire)

The exothermic chain reaction that sustains the combustion process.

Combustion

A chemical process that involves a rapid reaction with an oxidant (usually oxygen) to produce heat and light.

Conduction

Heat transfer through direct contact, mostly in solids.

Convection

Heat transfer through gases or liquids.

Decay Stage (of fire)

The stage of fire development where fuel and oxygen levels drop, causing the fire to weaken.

Dry Chemical Extinguisher

A fire extinguisher that uses a fine powder to coat the fuel and disrupt the chemical reaction of the fire.

Evacuate

To leave a dangerous area.

Fire Tetrahedron

A model representing the four essential components of fire: heat, fuel, oxygen, and a chemical chain reaction.

Flashover

A sudden and near-simultaneous ignition of all combustibles in a room when temperatures reach a critical point.

Fuel (in fire)

A combustible material in solid, liquid, or gaseous form that sustains the fire.

Fully-Developed Fire Stage

The stage when a fire has reached its peak temperature and intensity, consuming nearly all available fuel and oxygen.

Growth Stage (of fire)

The stage of rapid increase in a fire’s heat release rate and flame spread.

Heat (in fire)

Energy that raises the temperature of fuel to its ignition point.

Ignition Stage (of fire)

The initial stage of fire development when the fire is small and contained.

Oxidizing Agent

A substance that supports combustion; oxygen is the most common.

Pyrolysis

The breakdown of solid fuels into gaseous form via heat.

Radiation

Heat transfer via electromagnetic waves, requiring no direct contact.

Rollover

Hot gases rise to the ceiling and spread horizontally, creating rolling flames overhead.

Vaporization

The transformation of liquid fuel into gas.