Fire Dynamics Terminology

Question 1

Autoignition

Answer 1

Initiation of combustion by the heat but without a spark or flame.

Question 2

Autoignition Temperature

Answer 2

The lowest temp. at which a combustible material ignites in air without a spark of flame.

Question 3

Backdraft

Answer 3

Instantaneous explosion or rapid burning of superheated gases that occur when oxygen is introduced into a oxygen-depleted confined space.

Question 4

Carbon-Dioxide

Answer 4

Colourless, odourless, dangerous gas that neither supports combustion nor burns. (Used in portable Fire Extinguishers as an extinguishing agent to extinguish Class B or C fires by smothering or displacing oxygen)

Question 5

Carbon Monoxide

Answer 5

Colourless, odourless, dangerous gas formed by the incomplete combustion of carbon.

Question 6

Chemical Flame Inhibition

Answer 6

Extinguishment of a fire by interruption of the chemical chain reaction.

Question 7

Combustion

Answer 7

A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either a glow or flame.

Question 8

Combustion Zone

Answer 8

The area around a heat source in which there is sufficient air available to feed a fire.

Question 9

Conduction

Answer 9

Physical Flow or transfer of heat energy from one body to another, through direct contact or an intervening medium, from the point where the point where heat is produced to another location, or from a region of high temp to a region of low temp.

Question 9

Energy

Answer 9

the capacity to perform work.

Question 9

Convection

Answer 9

Transfer of heat by the movement of heated fluids or gases, usually in an upward direction.

Question 10

Endothermic reaction

Answer 10

A chemical reaction in which a substance absorbs heat.

Question 10

Exothermic Reaction

Answer 10

Chemical Reaction between two or more materials that changes the material and produces heat

Question 10

Flashover

Answer 10

Rapid transition from the growth stage to the fully developed stage.

Question 10

Fire Point

Answer 10

Temp. at which the a liquid fuel produces a sufficient vapours to support combustion once the fuel ignites. Fire Point is usually a few degrees above flash point.

Question 11

Flammable Explosive Range

Answer 11

The range between the UEL and LEL to which a substance can ignite.

Question 11

Fuel-Limited

Answer 11

Fire with adequate oxygen in which the HRR and growth rate are determined by the characteristics of the fuel.

Question 11

Flash Point

Answer 11

Minimum temp. at which a liquid gives off enough vapours to form an ignitable mixture with air near the surface of the liquid.

Question 12

Heat

Answer 12

Form of energy associated with the motion of the atoms and molecules which is transferred from one body to another as a result of temp. differences between the bodies.

Question 13

Heat Flux

Answer 13

The measure of the rate of heat transfer to or from a surface, typically expressed in (kW/m2)

Question 14

Heat Release Rate (HRR)

Answer 14

Total amount of heat release per unit time. Measured in kW or MW

Question 15

Hydrogen Cyanide

Answer 15

Colourless, toxic, and flammable liquid until it reaches 79°(26°C). Produced by the combustion of nitrogen-bearing substances

Question 16

Lower Explosive (flammable) Limit (LEL)

Answer 16

Lower limits at which a flammable gas or vapour will ignite and support combustion. Below this limit gases are too lean or thin to burn

Question 17

Miscible

Answer 17

Materials that are capable of being mixed in all proportions

Question 18

Piloted Ignition

Answer 18

Moment when a mixture of fuels and oxygen encounter and external heat source with sufficient heat or thermal energy to start the combustion reaction.

Question 19

Polar Solvants

Answer 19

Flammable liquids that have an attraction to water.

Question 20

Power

Answer 20

the amount of energy delivered over a given period of time.

Question 21

Pyrolysis

Answer 21

The Chemical decomposition of a solid material by heating. Precede combustion of a solid material.

Question 22

Radiation

Answer 22

Transmission or transfer of heat energy from one body to another body of a lower temp.through intervening space by electromagnetic waves.

Question 23

Reducing Agent

Answer 23

Fuel that is being oxidized or burned during combustion

Question 24

Rollover

Answer 24

Conditions in which the unburned fire gases that have accumulated at the top of a compartment ignite and flames propagate through the hot gas layer or across the ceiling.

Question 25

Smoke Explosion

Answer 25

Forms of fire gas ignition. The ignition of accumulated flammable products of combustion and air that are within their flammable range.

Question 26

Solubility

Answer 26

Degree to which a solid, liquid, or gas dissolves in a solvent (usually water)

Question 27

Spontaneous Ignition

Answer 27

Initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material

Question 28

Temperature

Answer 28

Measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units or degrees of temp.

Question 29

Upper Explosive (Flammable) Limit

Answer 29

Upper limit at which flammable gas or vapours will ignite. Gas or vapours are too rich to burn. (Lacks proper quantity of oxygen)

Question 30

Vaporization

Answer 30

Physcial process that changes a liquid into a gaseous state.

Question 31

Ventilation-Limited

Answer 31

Fire with limited ventilation in which the HRR or growth is limited by the amount of oxygen available to the fire (also known as Ventilation-controlled)