Chapter 5 Fire Behavior

Front 1

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

Back 1

Combustion

Front 2

A rapid self-sustaining oxidation process accompanied with the evolution of heat and light in varying intesities

Back 2

Fire

Front 3

A form of energy characterized by vibration of molecules and capable of initiating and sustaining chemical changes and changes of state

Back 3

Heat

Front 4

Measure of a materials ability to transfer heat energy to other objects. Measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of degrees

Back 4

Temperature

Front 5

A material that will maintain combustion under specified environmental conditions

Back 5

Fuel

Front 6

Any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials.

Back 6

Oxidizer

Front 7

Anything that occupies space and has mass

Back 7

Matter

Front 8

Capacity to perform work; occurs when a force is applied to an object over a distance, or when a chemical, biological, or physical transformation is made in a substance

Back 8

Energy

Front 9

Chemical process that occurs when a substance combines with an oxidizer such as oxygen in the air

E.G., rust on metal

Back 9

Oxidation

Front 10

Stored energy possessed by an object that can be released in the future to perform work once released

Back 10

Potential Energy

Front 11

The energy possessed by a body because of its own motion

Back 11

Kinetic Energy

Front 12

The measure for energy

Back 12

Joules (J)

Front 13

The amount of energy required to change the temperature of one gram of water 1 degree Celsius

Back 13

4.2J

Front 14

Chemical reaction that releases thermal heat or energy

Back 14

Exothermic Reaction

Front 15

Chemical reaction that absorbs thermal heat or energy

Back 15

Endothermic Reaction

Front 16

The chemical decomposition of a solid material by heating

Often produces combustion

Offgassing

Back 16

Pyrolysis

Front 17

Physical process that changes a liquid into a gaseous state. The rate of which depends on the substance involved, heat, pressure, and exposed surface area

Back 17

Vaporization

Front 18

The process of initiating self-sustained combustion

Back 18

Ignition

Front 19

Moment when a mixture of fuel and oxygen encounters an external heat source with sufficient heat or thermal energy to start the combustion reaction

Back 19

Piloted Ignition

Front 20

Initiation of combustion by heat but without spark or flame

Back 20

Autoignition

Front 21

The lowest temperature at which a combustible material ignites in air without a spark or flame

Back 21

Autoignition Temperature

Front 22

Visible, luminous body of a burning gas emitting radiant energy including light of various colors given off by burning gases or vapors during combustion

Back 22

Flame

Front 23

Model used to explain the elements required for combustion. Heat, Oxygen, and Fuel; removal of any one of these elements results in extinguishment

Back 23

Fire Triangle

Front 24

Model of the four elements required for combustion. Heat, Oxygen, Fuel, and a Self-Sustaining Chemical Reaction; removal of any one of these elements results in extinguishment

Back 24

Fire Tetrahedron

Front 25

Materials that absorb heat but do not actively participate in the combustion process

Back 25

Passive Agent

Front 26

Materials produced and released during burning

Back 26

Products of Combustion

Front 27

Colorless, odorless, dangerous gas formed by incomplete combustion of carbon. Chemical asphyxiant that binds with hemoglobin preventing those cells from distributing oxygen to the body

Back 27

Carbon Monoxide (CO)

Front 28

Colorless, faint odor similar to bitter almonds, produced in the combustion of materials containing nitrogen. Chemical asphyxiant preventing the body from using oxygen at the cellular level

Back 28

Hydrogen Cyanide (HCN)

Front 29

Product of complete combustion of organic materials. Colorless, odorless, and neither supports combustion or burns. Simple asphyxiant displacing oxygen from the air

Back 29

Carbon Dioxide (CO2)

Front 30

The kinetic energy associated with the random motions of the molecules of a material object; often used interchangeably with the terms heat and heat energy.

Measured in Joules or Btu

Back 30

Thermal Energy

Front 31

The result of exothermic reactions, occurring spontaneously in some materials under certain conditions, whereby heat is generated at a rate sufficient to raise the temperature of the material

Back 31

Self-Heating

Front 32

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

Back 32

Spontaneous Ignition

Front 33

-The insulation properties of the material immediately surrounding the fuel must be such that the heat cannot dissipate as fast as it is being generated

-The rate of heat production must be great enough to raise the temperature of the material to its autoignition temperature

-The available air supply in and around the material being heated must be adequate to support combustion

Back 33

Factors required for spontaneous iginition

Front 34

Chemical, mechanical, electrical, light, nuclear, and sound energy are all sources of what

Back 34

Sources of Thermal Energy

Front 35

-Resistance heating

-Overcurrent or overload

-Arcing

-Sparking

Back 35

Types of Electrical Heating

Front 36

When electric current flows through a conductor, heat is produced

Back 36

Resistance Heating

Front 37

When the current flowing through a conductor exceeds its design limits, it may overheat and present an ignition hazard

Unintended resistance heating

Back 37

Overcurrent or Overload

Front 38

In general a high-temperature luminous electric discharge across a gap or through a medium such as charred insulation.

The luminous discharge

Back 38

Arching

Front 39

When an electric arc occurs, luminous particles can be formed and spatter away from the point of arcing

The spatter

Back 39

Sparking

Front 40

Energy generated by friction or compression

Back 40

Mechanical Energy

Front 41

Transfer of thermal energy over time per unit of surface area

Measured in killowatts per meter squared

Back 41

Heat Flux

Front 42

Conduction

Convection

Radiation

Back 42

The ways heat can be transferred from one body to another

Front 43

Transfer of heat through or between solids that are in direct contact

Back 43

Conduction

Front 44

The transfer of heat within a medium such as a gas or liquid

Back 44

Convection

Front 45

The transfer of heat by way of electromagnetic energy

Back 45

Radiation

Front 46

The tendency or capacity to remain afloat in a liquid or rise in air or gas

Back 46

Buoyant

Front 47

Composed of at least one inlet opening, one exhaust opening, and the connecting volume between the openings

The direction of the flow is determined by difference in pressure

Heat and smoke will flow toward areas of lower pressure

Back 47

Flow Path

Front 48

Effects of radiant heat decrease as

Back 48

Distance increases

Front 49

Dark materials emit and absorb heat more effectively than lighter color materials; smooth or highly-polished surfaces reflect more radiant heat than rough surfaces

Back 49

Factor that the nature of exposed surfaces influences radiant heat transfer

Front 50

Buoyant layer of hot gases and smoke produced by a fire in a compartment

Back 50

Upper Layer

Front 51

Temperature difference has a major effect on heat transfer through radiation. As the temperature of the heat source increases, the radiant energy increases by a factor to the fourth power.

Back 51

Temperature Difference between the Heat and Exposed Surfaces

Front 52

The fuel that is being oxidized or burned during combustion

Back 52

Reducing Agent

Front 53

Total amount of thermal energy that could be generated by the combustion reaction if a fuel were completely burned. The heat of combustion is measured in Btu per pound or Megajoules per kilogram

Back 53

Heat of Combustion

Front 54

Total amount of heat released per unit time. Measured in kilowatts and megawatts of output

Back 54

Heat Release Rate (HRR)

Front 55

The rate at which energy is being transferred over time

Back 55

Power

Front 56

A unit of measure of power or rate of work equal to one joule per second

Back 56

Watt

Front 57

Weight of a given volume of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure. Less than 1 is lighter than air

More than 1 is heavier than air

Back 57

Vapor Density

Front 58

Weight of a substance compared to the weight of an equal volume of water at a given temperature

Less than 1 floats on water

More than 1 sinks in water

Back 58

Specific Gravity

Front 59

Any liquid having a flash point below one hundred degrees and a vapor pressure not exceeding forty psi absolute

Back 59

Flammable Liquid

Front 60

Measure of the tendency of a substance to evaporate

The pressure at which a vapor is in equilibrium with its liquid phase for a given temperature; liquids that have a greater tendency to evaporate have higher vapor pressures for a given temperature

Back 60

Vapor Pressure

Front 61

Minimum temperature at which a liquid gives off enough vapors to form an ignitable mixture with air near the liquid's surface, but not sustain combustion

Back 61

Flash Point

Front 62

Temperature at which a liquid fuel produces sufficient vapors to support combustion once the fuel is ignited. Must exceed 5 seconds of burning duration during the test.

Back 62

Fire Point

Front 63

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

Back 63

Solubility

Front 64

Materials that are capable of being mixed in all proportions

Back 64

Miscible

Front 65

Petroleum based organic compound that contains only hydrogen and carbon

Back 65

Hydrocarbon Fuel

Front 66

Flammable liquids that have an attraction for water. Mix readily with water.

Back 66

Polar Solvents

Front 67

Liquid having a flash point at or above one hundred degrees and below two hundred degrees

Back 67

Combustible Liquid

Front 68

Normal Oxygen Level in the Air

Back 68

21% oxygen in the air

Front 69

Oxygen Deficient Environment

Back 69

Less than 19.5% oxygen in the air

Front 70

Oxygen Enriched Environment

Back 70

More than 23.5% oxygen in the air

Front 71

The range between the upper flammable limit and lower flammable limit in which a substance can be ignited

Back 71

Flammable (Explosive) Range

Front 72

Upper limit at which a flammable gas or vapor will ignite; above this limit the gas or vapor is too rich to burn

Back 72

Upper Flammable Limit (UFL)

Front 73

Lower limit at which a flammable gas or vapor will ignite and support combustion; below this limit the gas or vapor is too lean

Back 73

Lower Flammable Limit (LFL)

Front 74

Molecular fragments that are highly reactive

Back 74

Free Radicals

Front 75

Extinguishment of a fire by interruption of the chemical chain reaction

Back 75

Chemical Flame Inhibition

Front 76

Incipient, Growth, Fully Developed, and Decay

Back 76

Stages of Fire Development

Front 77

-Fuel Type

-Availability and location of additional fuels

-Compartment volume and ceiling height

-Ventilation

-Thermal properties of the compartment

-Ambient conditions

-Fuel Load

Back 77

Factors that Affect Fire Development

Front 78

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

Back 78

Fuel-Controlled

Front 79

A fire with limited ventilation in which the HRR or growth is limited by the amount of oxygen available to the fire

Back 79

Ventilation-Controlled

Front 80

Common, prevailing, and uncontrolled atmospheric weather conditions.

Back 80

Ambient Conditions

Front 81

The total quantity of combustible contents of a building, space, or fire area, including interior finish and trim, expressed in heat units of the equivalent weight in wood.

Back 81

Fuel Load

Front 82

First stage of the burning process in a compartment in which the substance being oxidized is producing some heat, but the heat has not spread to other substances nearby. During this phase, the oxygen content of the air has not been significantly reduced and the temperature within the compartment is not significantly higher than the ambient temperature.

Back 82

Incipient Stage

Front 83

The column of hot gases, flames, and smoke rising above a fire.

AKA: convection column, thermal updraft, or thermal column

Back 83

Plume

Front 84

A relatively thin layer of flowing hot gases that develops under a horizontal surface as a result of plume impingement and the flowing gas being forced to move horizontally.

Mushrooming

Back 84

Ceiling Jet

Front 85

During this stage of fire, oxygen and fuel are plentiful

Back 85

Incipient

Front 86

During this stage of fire, the fire influences the environment and begins to be influenced by the ventilation conditions of the compartment.

Back 86

Growth

Front 87

Outcome of combustion in a confined space in which gases tend to form into layers, according to temperature, with the hottest gases found at the ceiling and the coolest gases at floor level

AKA: heat stratification, thermal balance

Back 87

Thermal Layering

Front 88

The level at a compartment opening where the difference in pressure exerted by expansion and buoyancy of hot smoke flowing out of the opening and the inward pressure of cooler, ambient temperature air flowing in through the opening is equal.

Back 88

Neutral Plane

Front 89

A rapid transition from growth to fully developed

Back 89

Flashover

Front 90

All combustible materials actively burn during this stage

Back 90

Fully Developed

Front 91

The fire begins to cool and die as fuel and/or ventilation run out of supply during this stage

Back 91

Decay

Front 92

A condition where 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

Back 92

Rollover

Front 93

The explosive burning of heated gases that occurs when oxygen is introduced into a compartment that has a high concentration of flammable gases and a depleted supply of oxygen due to an existing fire

Back 93

Backdraft

Front 94

Transition in fire development- Flashover represents a transition from the growth stage to the fully developed stage

Rapidity- Although not instantaneous, flashover happens rapidly

Compartment- There must be an enclosed space such as a single room or enclosure

Ignition of all exposed surfaces- Virtually all combustible surfaces in the enclosed space become ignited

Back 94

The Four Common Elements of Flashover

Front 95

Flashover

Backdraft

Smoke Explosion

Back 95

Three Types of Rapid Fire Development

Front 96

Form of fire gas ignition; the ignition of accumulated flammable products of combustion and air that are within their flammable range.

Back 96

Smoke Explosion

Front 97

Temperature reduction

Fuel removal

Oxygen exclusion

Chemical flame inhibition

Ventilation and fire behavior

Back 97

Ways Firefighters Influence Fire Behavior

Front 98

Planned, systematic, and coordinated removal of heated air, smoke, gases or other airborne contaminants from a structure, replacing them with cooler and/or fresher air to meet the incident priorities of life safety, incident stabilization, and property conservation.

Back 98

Tactical Ventilation

Front 99

The most commonly found oxidizer

Back 99

Oxygen in the air