Chapter 5: Fire Behavior

Question 1

Class A fires involve:

Answer 1

Ordinary combustible materials

Question 2

Class B fires involve:

Answer 2

Flammable or combustible liquids

Question 3

Class C fires involve:

Answer 3

Energized electrical equipment

Question 4

Class D fires involve:

Answer 4

Combustible metals

Question 5

Class K fires involve:

Answer 5

Combustible cooking oils and fats

Question 6

What is a BLEVE?

Answer 6

A type of explosion that occurs when volatile liquid in a tank is heated

Question 7

What does BLEVE stand for?

Answer 7

Boiling Liquid/Expanding Vapor Explosion

Question 8

A smoke explosion occurs when:

Answer 8

A mixture of flammable gases and oxygen is present, usually in a void or other space, comes in contact with an ignition source

Question 9

What are the four elements necessary for a self sustaining fire?

The fire tetrahedron

Answer 9

Oxygen
Fuel
Heat
Chemical chain reaction

Question 10

What danger is suggested when you observe smoke puffing in and out of a structure?

Answer 10

Backdraft

Question 11

Combustion

Answer 11

Rapid chemical process of oxidation that produces light and heat

Question 12

4 ways of heat transfer

Answer 12

Conduction
Convection
Radiation
Direct flame impingement

Question 13

4 stages of fire development

Answer 13

1. Incipient stage
2. Growth stage
3. Fully developed stage
4. Decay stage

Question 14

Fire point (flame point)

Answer 14

The lowest temperature at which a liquid produces enough vapor to sustain a continuous fire

Question 15

Oxidation

Answer 15

Process in which oxygen combines chemically with another substance to create a new compound

EX) rust

Question 16

Wind conditions as low as ___ mph can create wind-driven fire conditions

Answer 16

10

Question 17

Vapor density

Answer 17

Refers to the weight of a vapor or gas compared to the weight of an equal volume of air

Question 18

The vapor density of air is assigned the value of:

A gas with a lower vapor density will:
A gas with a high vapor density will:

Answer 18

1

Rise
Fall

Question 19

Most common method of extinguishing a fire

Answer 19

Cool the burning material

Question 20

What does LEL stand for?
Also called LFL

Answer 20

Lower Explosive Limit
Lower Flammable Limit

Question 21

What does UEL stand for?
Also called UFL

Answer 21

Upper Explosive Limit
Upper Flammable Limit

Question 22

How can class B fires be extinguished?

Answer 22

Shuttting off the supply of fuel
Using foam to exclude the oxygen

Question 23

Exothermic

Answer 23

Chemical reaction that produces heat

EX) fire

Question 24

Endothermic

Answer 24

Chemical reaction that absorbs heat

EX) ice cubes melting

Question 25

Pyrolysis

Answer 25

Process in which materials are decomposed, or broken down, into simple compounds by heat alone Produces a flammable vapor

Question 26

What state must a fuel be in for combustion to take place?

Answer 26

Vapor only

Question 27

Rollover

Answer 27

A condition where flames move through or across unturned gasses Usually occurs at ceiling level Warning sign of flashover

Question 28

Flashover

Answer 28

Occurs when all contents of a room with fire gets superheated and begin to release gases that ignite simultaneously

Question 29

Flammability range and explosives limits are ____ terms

Answer 29

Interchangeable

Question 30

Black fire

Answer 30

High-volume, high-velocity, turbulent, ultra-dense, black smoke

Question 31

What is the approximate critical temperature for a flashover to occur?

Answer 31

1000° F

Question 32

What is smoke-stained glass a warning sign of?

Answer 32

Backdraft

Question 33

Introducing air into a ventilation-limited fire can result in:

Answer 33

Explosive fire growth

Question 34

What are the 4 key attributes of smoke

Answer 34

Smoke volume, velocity, density, and color

Question 35

When you open the door and Smoke exits through the top half of the doorway: Smoke rises and the opening clears out: Smoke thins but remains at the doorway: The fire is located

Answer 35

Same level Above Below

Question 36

Thermal layering

Answer 36

Heat layers that occurs in a room from a fire

Question 37

Turbulent smoke is an indication of:

Answer 37

A flashover

Question 38

Flash point

Answer 38

The lowest temperature at which a liquid or solid produces a flammable vapor