Ch 4 - Fire Dynamics

Question 1

Pyrolysis

Answer 1

the chemical decomposition of a solid into a gas by heating

Question 2

Autoignition

Answer 2

the fuel is heated to the point at which combustion can occur without the need for a flame or spark

Question 3

Fire triangle

Answer 3

heat, oxygen, fuel

Question 4

Fire tetrahedron

Answer 4

heat, oxidizer, fuel (reducing agent), chemical chain reaction

Question 5

Carbon-based fuels

Answer 5

wood, cotton

Question 6

Hydrocarbon fuels

Answer 6

plastics, synthetic fibers, petroleum products

Question 7

Vapor density

Answer 7

the density of gases in relation to air

Question 8

Specific gravity

Answer 8

ratio of density of a given liquid to the density of water

Question 9

Flash point

Answer 9

minimum temperature at which a liquid gives off sufficient vapors to ignite, but not sustain combustion

Question 10

Fire point

Answer 10

temperature at which sufficient vapors will begin a sustained combustion reaction

Question 11

Solubility

Answer 11

the extent to which a substance will mix with water

Question 12

Miscible

Answer 12

materials that are capable of being mixed in all proportions

Question 13

Polar solvents

Answer 13

alcohols, mix with water, flammable

Question 14

Stages of Fire Development

Answer 14

Incipient, Growth, Fully Developed, Decay

Question 15

Incipient Stage

Answer 15

ignition when three elements of fire triangle come together. Fire is small and contained to fuel of origin

Question 16

Growth Stage

Answer 16

More of initial fuel becomes involved and will begin to spread to other nearby fuels

Question 17

Fully Developed Stage

Answer 17

all combustible materials in the compartment are burning at their peak heat release rate based on the available oxygen

Question 18

Decay Stage

Answer 18

Heat release rate begins to decline as the amount of available fuel or oxygen begins to decrease

Question 19

Neutral plane

Answer 19

the interface between the stratified layers of hot gas and cool air

Question 20

Flashover

Answer 20

rapid transition from growth stage to fully developed when all combustible materials and fuel gases in a compartment ignite

Question 21

Two Biggest Factors Influencing Danger of Structure Fire

Answer 21

1) Fuel load
2) Building construction/integrity

Question 22

Legacy Construction Benefits

Answer 22

smaller compartments, more compartments, operational windows, air pockets as insulation

Question 23

Modern Construction Detriments

Answer 23

Open floor plans, high ceilings, lightweight manufactured structural elements, sealed windows, synthetic insulation