Chapter 6: Fire Behavior

The flash point of gasoline is?

-45 F (-43 C )

A gas with a vapor density of __ will rise in air.

0.1

What is the vapor density of air?

1.0

The critical temperature for a flashover to occur is ____ degrees F.

1000

What is the percentage of oxygen normally found in air?

21%

Matter exists in ____ states.

3

Which class of fire involves ordinary combustibles such as wood and paper?

A

An endothermic reaction is one that?

Absorb heat

Small solid particles or liquid droplets that are suspended in air.

Aerosols

What is the relationship between resistance and heat as electricity flows through a wire?

As resistance increase , heat increases.

The smallest particle of an element, which can exist alone or in combination.

Atom

Flammable liquid fires are considered class?

B

A phenomenon that occurs when a fire takes place in a confined area, such as a sealed aircraft fuselage, and burns undetected until most of the oxygen within is consumed. The heat continues to produce flammable gases, mostly in the form of carbon monoxide. These gases are heated above their ignition temperature and when a supply of oxygen is introduced, as when normal entry points are opened, the gases could ignite with explosive force (NFPA 402).

Backdraft

What does smoke puffing in and out of a structure indicate?

Backdraft conditions

A hot, high-volume, high-velocity, turbulent, ultra-dense black smoke that indicates an impending flashover or autoignition.

Black fire

What is the term for high-volume, high- velocity, turbulent , ultra-dense black smoke?

Black fire

An explosion that occurs when a tank containing a volatile liquid at the bottom of the tank and a flammable gas at the top of the tank is heated to the point where the tank ruptures.

Boiling Liquid Expanding Vapor Explosion (BLEVE)

A burning structure

Box

How do you determine the flammability of the mixture?

By the compound with the lowest ignition temperature.

Energy that is created or released by the combination of decomposition of chemical compounds.

Chemical energy

A fire in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics. (NFPA 10)

Class A fire

A fire in flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, alcohols, and flammable gases. (NFPA 10)

Class B Fire

A fire that involves energized electrical equipment. (NFPA 10)

Class C fire

A fire in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium. (NFPA 10)

Class D fire

A fire in cooking appliance that involves combustible cooking media (vegetable or animal oils & fats). (NFPA 10)

Class K fires

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. (NFPA 101)

Combustion

A space completely enclosed by walls and a ceiling. The compartment enclosure is permitted to have openings in walls to an adjoining space if the openings have a minimum lintel depth of 8 inches (203 mm) from the ceiling and the openings do not exceed 8 feet (2.44 m) in width. A single opening of 36 inches (914 mm) or less in width without a lintel is permitted when there are no other openings to adjoining spaces. (NFPA 13)

Compartment

Heat transfer to another body or within a body by direct contact. (NFPA 921)

Conduction

Heat transfer by circulation within a medium such as a gas or a liquid. (NFPA 921)

Convection

The majority of fires are extinguished by which method?

Cooling the fuel

The stage of fire development in which the fire has consumed either the available fuel or oxygen and starting to die down.

Decay stage

Heat that is produced by electricity.

Electrical energy

What is a danger to consider when attacking a class C fire?

Electrical injury

Reactions that absorb heat or require heat to be added.

Endothermic

A Class C fire involves?

Energized electrical equipment

What is the method of choice for extinguishing most Class B fires?

Excluding oxygen

What is the method of choice for extinguishing most class B fires?

Excluding the oxygen

Reactions that result in the release of energy in the form of heat.

Exothermic

What is another term for flammability limits?

Explosive Limits

A rapid, persistent chemical reaction that releases both heat and light.

Fire

A geometric shape used to depict the four components required for a fire to occur: fuel, oxygen, heat, and chemical chain reactions.

Fire Tetrahedron

A geometric shape used to depict the three components of which a fire is composed: fuel, oxygen, and heat.

Fire Triangle

The lowest temperature at which a substance releases enough vapors to ignite and sustain combustion.

Flame point

What is the term for the spontaneous ignition of hot gases at the upper level of a room?

Flameover

The upper and lower concentration limits (at a specified temperature and pressure) of a flammable gas or vapor in air that can be ignited, expressed as a percentage of the fuel by volume.

Flammability limits

Transition stage in the development of a compartment fire in which surfaces exposed to thermal radiation reach ignition temperature more or less simultaneously and fire spreads rapidly throughout the space, resulting in full room involvement or total involvement of the compartment or enclosed space. (NFPA 921)

Flashover

The volume in a structure between an inlet and an outlet that allows the movement of heat and smoke from the higher pressure within the fire area toward the lower-pressure areas accessible via doorways, halls, stairs, and window openings.

Flow path

A material that will maintain combustion under specified environmental conditions. (NFPA 53)

Fuel

The stage where the fire is consuming the maximum amount of fuel possible. It achieves the maximum heat release rate possible for the fuel supply and oxygen present.

Fully Developed Stage

Flashover occurs during which phase of fire?

Fully developed

In which state of matter does the product tend to expand indefinitely?

Gas

As a fire continues to grow and the amount of heat generated increases, you may notice small flames "dancing" in the hot gas layer. These isolated flames are an indication of?

Gases being within their flammable range

The stage of fire development in which the fire is spreading beyond the point of origin and beginning to involve other fuels in the immediate area.

Growth stage

Which of the following is a side of the fire triangle?

Heat

The measure of the rate of heat transfer from one surface to another. It is measured in kilowatts per meter squared (KW/m2) or Btu/ft2.

Heat flux

Which toxic gas is commonly produced by fire?

Hydrogen Cyanide (HCN)

A state of inadequate oxygenation of the blood & tissue sufficient to cause impairment of function.

Hypoxia

The action of setting something on fire.

Ignition

Minimum temperature a substance should attain to ignite under specific test conditions. (NFPA 921)

Ignition Temperature

The initial or beginning stage of a fire, in which it can be controlled or extinguished by portable extinguishers or small amounts of dry extinguishing agents, without the need for protective clothing or breathing apparatus. (NFPA 484)

Incipient stage

What are the 4 stages of fire?

Incipient stage Growth stage Fully developed stage Decay stage

Fires involving combustible cooking media, such as oils and grease, are considered class?

K

Smooth or streamlined movement of smoke, which indicates that the pressure in the building is not excessively high.

Laminar smoke flow

Any material that (1) has fluidity greater than that of 300 penetration asphalt. (2) is a viscous substance for which a specific melting point cannot be determined but that is determined to be a liquid.

Liquid

That concentration of a combustible material in air below which ignition will not occur; also known as the lower explosive limit (LEL). Mixtures below this limit are said to be "too lean." (NFPA 329)

Lower Flammable Limit (LFL)

A substance made up of atoms & molecules.

Matter

Friction is a form of ____ energy.

Mechanical

A form of potential energy that can generate heat through friction loss.

Mechanical energy

The interface at a vent, such as a doorway or a window opening, between the hot gas flowing out of a fire compartment and the cool air flowing into the compartment where the pressure differences between interior & exterior is zero.

Neutral Plane

Reaction with oxygen either in the form of the element or in the form of one of its compounds. (NFPA 53)

Oxidation

In which process is a new compound created from the combination of oxygen and another substance?

Oxidation (rust)

The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column. (NFPA 921)

Plum

The destructive distillation of organic compounds in an oxygen-free environment that converts the organic matter into gases, liquids, and char. (NFPA 820)

Pyrolysis

The emission and propagation of energy through matter of space by means of electromagnetic disturbances that display both wave-like and particle-like behavior. (NFPA 801)

Radiation

A gas with a vapor density of less than 1 will?

Rise

The condition where unburned fuel (pyrolysate) from the originating fire has accumulated in the ceiling layer to a sufficient concentration (at or above the lower flammable limit) that it ignites and burns. This can occur without ignition of, or prior to, the ignition of other fuels separate from the origin.

Rollover

A gas with a vapor density greater than 1 will?

Settle close to the ground

Smoke that is produce by ordinary household materials when they are first heated has which sort of appearance?

Slow moving and white

The airborne solid and liquid particulates and gases evolved when a material undergoes pyrolysis or combustion, together with the quantity of air that is entrained or otherwise mixed into the mass.

Smoke

A violent release of confined energy that occurs when a mixture of flammable gases & oxygen are present, usually in a void or other area separate from the fire compartment, and come in contact with a source of ignition. In smoke explosion, there is no charge to the ventilation profile, such as an open door or window; rather it occurs from the travel of smoke within the structure to an ignition source.

Smoke Explosion

The speed of smoke leaving a burning building.

Smoke Velocity

The quantity of smoke, which indicates how much fuel is being heated.

Smoke Volume

The attribute of smoke that reflects the stage of burning of a fire and the material that is burning in the fire.

Smoke color

The thickness of smoke. Because it has a high mass per unit volume, smoke is difficult to see through.

Smoke density

One of the three stages of matter; a material that has three dimensions and is firm in substance.

Solid

The degree of sensible heat of a body as measures by a thermometer or similar instrument.

Temperature

Which geometric figure is used to represent the four elements required for a self-sustaining fire?

Tetrahedron

Which situation is indicated if you open a door and the smoke rises and the opening clears out?

The fire is above the level of the door.

Which situation is indicated when you open a door and the smoke thins, but the smoke still fills the door?

The fire is below the level of the door.

Which situation is indicated when you open a door and the smoke exits through the top half of the door and clean air enters through the bottom half?

The fire is on the same level as the door.

Which form of heat transfer travels in all direction?

Thermal radiation

Which sign is an indication of possible backdraft condition?

Turbulent, pressurized smoke

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

Vapor only

Upward spread of fire within a structure is primarily caused by which form of heat transfer?

convection

During the ___ phase, fire has consumed either the available fuel or oxygen, and temperature drops.

decay

Turbulent smoke is an indication of impending?

flashover

When water is converted to steam, it occupies ____ ____ space.

much more

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

vapor