Chapter 5 Fire Behavior Flashcards
The smallest particle of an element, which can exist alone or in combination.
Atom
A deflagration (explosion) resulting from the sudden introduction of air into a confined space containing oxygen-deficient products of incomplete combustion.
Backdraft
A hot, high-volume, high-velocity, turbulent, ultra-dense black smoke that indicates an impending flashover or autoignition.
Black fire
An explosion that occurs when pressurized liquefied materials (e.g., propane or butane) inside a closed vessel are exposed to a source of high heat.
Boiling liquid/expanding vapor explosion (BLEVE)
The temperature at which the vapor pressure of a liquid equals the surrounding atmospheric pressure.
Boiling point
A colorless, odorless, electrically nonconductive inert gas that is a suitable medium for extinguishing Class B and Class C fires.
Carbon dioxide
A toxic gas produced through incomplete combustion.
Carbon monoxide (CO)
Energy that is created or released by the combination or decomposition of chemical compounds.
Chemical energy
A fire in ordinary combustible materials, such as wood, cloth, paper, rubber, and many plastics.
Class A fire
A fire in flammable liquids, combustible liquids, petroleum greases, tars, oils, oil-based paints, solvents, lacquers, alcohols, and flammable gases.
Class B fire
A fire that involves energized electrical equipment.
Class C fire
A fire in combustible metals, such as magnesium, titanium, zirconium, sodium, lithium, and potassium.
Class D fire
A fire in a cooking appliance that involves combustible cooking media (vegetable or animal oils and fats).
Class K fire
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 a flame.
Combustion
A space completely enclosed by walls and a ceiling. Each wall in the compartment is permitted to have openings to an adjoining space if the openings have a minimum lintel depth of 8 in. (200 mm) from the ceiling and total width of the openings in each wall does not exceed 8 ft (2.4 m). A single opening of 36 in. (900 mm) or less in width without a lintel is permitted when there are no other openings to adjoining spaces.
Compartment
Heat transfer to another body or within a body by direct contact.
Conduction
Heat transfer by circulation within a medium such as a gas or a liquid.
Convection
The stage of fire development within a structure characterized by either a decrease in the fuel load or available oxygen to support combustion, resulting in lower temperatures and lower pressure in the fire area.
Decay stage
Heat that is produced by electricity.
Electrical energy
Reactions that absorb heat or require heat to be added.
Endothermic
Reactions that result in the release of energy in the form of heat.
Exothermic
A rapid, persistent chemical reaction that releases both heat and light.
Fire
The lowest temperature at which a liquid will ignite and achieve sustained burning when exposed to a test flame in accordance with ASTM 92, Standard Test Method for Flash and Fire Points by Cleveland Open Cup Tester.
Fire point
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 range in concentration between the lower and upper flammable limits.
Flammable range (explosive limits)
A transition phase 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.
Flashover
The minimum temperature at which a liquid or a solid emits vapor sufficient to form an ignitable mixture with air near the surface of the liquid or the solid.
Flash point
The movement of heat and smoke from the higher pressure within the fire area toward the lower pressure within the fire area toward the lower pressure areas accessible via doors, window openings, and roof structures.
Flow path
A material that will maintain combustion under specified environmental conditions.
Fuel
A fire in which the heat release rate and fire growth are controlled by the characteristics of the fuel because there is adequate oxygen available for combustion.
Fuel-limited fire
The stage of fire development where heat release rate has reached its peak within a compartment.
Fully developed stage
The physical state of a substance that has no shape or volume of its own and will expand to take the shape and volume of the container or enclosure it occupies.
Gas
The stage of fire development where the heat release rate from an incipient fire has increased to the point where heat transferred from the fire and the combustion products are pyrolyzing adjacent fuel sources and the fire begins to spread across the ceiling of the fire compartment (rollover).
Growth stage
The measure of the rate of heat transfer to a surface, typically expressed in kilowatts per meter squared (kW/m2) or Btu/ft2.
Heat flux
The rate at which heat energy is generated by burning.
Heat release rate (HRR)
The movement of heat energy from a hotter medium to a cooler medium by conduction, convection, or radiation.
Heat transfer
An extremely toxic gas produced by the combustion of many common plastic-based materials. Low-level exposure can cause cyanosis, headache, dizziness, unsteady gait, and nausea.
Hydrogen cyanide
The action of setting something on fire.
Ignition
Minimum temperature a substance should attain in order to ignite under specific test conditions.
Ignition temperature
The early stage of fire development where the fire’s progression is limited to a fuel source and the thermal hazard is localized to the area of the burning material.
Incipient stage
A burning process in which the fuel is not completely consumed, usually due to a limited supply of oxygen.
Incomplete combustion
Smooth or streamlined movement of smoke, which indicates that the pressure in the building is not excessively high.
Laminar smoke flow
A fluid (such as water) that has no independent shape but has a definite volume and does not expand indefinitely and that is only slightly compressible.
Liquid
The minimum concentration of a combustible vapor or combustible gas in a mixture of the vapor or gas and gaseous oxidant, above which propagation of flame will occur on contact with an ignition source.
Lower explosive limit (LEL)
A form of potential energy that can generate heat through friction.
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 difference between the interior and exterior is equal.
Neutral plane
Reaction with oxygen either in the form of the element or in the form of one of its compounds.
Oxidation
A chemical agent that causes severe pulmonary damage; it is a by-product of incomplete combustion.
Phosgene
The column of hot gases, flames, and smoke rising above a fire; also called convection column, thermal updraft, or thermal column.
Plume
A process in which material is decomposed, or broken down , into simpler molecular compounds by the effects of heat alone.
Pyrolysis
The combined process of emission, transmission, and absorption of energy traveling by electromagnetic wave propagation (e.g., infrared radiation) between a region of higher temperature and a region of lower temperature.
Radiation
The condition in which unburned fuel (pyrolysate) from the originating fire has accumulated in the ceiling layer to a sufficient concentration (i.e., 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; also known as flameover.
Rollover
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
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
A violent release of confined energy that occurs when a mixture of flammable gases and oxygen is present, usually in a void or other area separate from the fire compartment, and comes in contact with a source of ignition. In this situation, there is no change 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 unburned, partially burned, and completely burned substances found in smoke.
Smoke particles
The speed of smoke leaving a burning building.
Smoke velocity
The quantity of smoke, which indicates how much fuel is being heated.
Smoke volume
One of the three stages of matter; a material that has three dimensions and is firm in substance.
Solid
The physical state of a material—solid, liquid, or gas.
States of matter
The degree of sensible heat as measured by a thermometer or similar instrument.
Temperature
A cylindrical area above a fire in which heated air and gases rise and travel upward.
Thermal column
The stratification (heat layers) that occurs in a room as a result of a fire.
Thermal layering
The means by which heat is transferred to other objects.
Thermal radiation
Agitated, boiling, angry-movement smoke, which indicates great heat in the burning building. It is a precursor to flashover.
Turbulent smoke flow
The maximum amount of gaseous fuel that can be present in the air if the air/fuel mixture is to be flammable or explosive.
Upper explosive limit (UEL)
The weight of an airborne concentration (vapor or gas) compared to an equal volume of dry air.
Vapor density
A fire in which the heat release rate and fire growth are regulated by the available oxygen within the space.
Ventilation-limited fire
The ability of a substance to produce combustible vapors.
Volatility
