Chapter 5 - Fire Behaviour Flashcards
The smallest particle of an element, which can exist alone or in a combination
Atom
A deflagration (explosion) from the sudden introduction of air into a confined space containing oxygen-deficient products of incomplete combustion (NFPA 1403)
Backdraft
A hot, high-volume, high velocity, turbulent, ultra-dense, black smoke that indicates an impending flashover or auto-ignitition.
Black Fire
An explosion that occurs when pressurized liquified materials (eg - propane/butane) inside a closed vessel are exposed to a source of high heat.
Boiling Liquid/Expanding Vapor Explosion
The temperature at which the vapor pressure of a liquid equals the surrounding atmospheric pressure (NFPA 1)
Boiling Point
A colorless, odorless, electrically non-conductive inert gas that is a suitable medium for extinguishing Class B and Class C fires (NFPA 10)
CO2/Carbon Dioxide
A toxic gas produced through incomplete combustion.
CO/ Carbon Monoxide
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 (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 Mg+, titanium, zirconium, sodium, lithium and K+
Class D fire
A fire in a cooking appliance that involves combustible cooking media (vegetable or animal oils and fats) (NFPA 10)
Class K fire
A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually in the form of either a flow or a flame (NFPA 1)
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 minumum lintel depth of 200mm (8in) from the ceiling and the total width of the openings in each wall does not exceed 2.4m (8ft). A single opening of 900mm (36in) 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 stage of fire development within a structure characterized by either a decrease in the fuel load or available oxygen to support combustion, resutling in the lower temperatures and lower pressure in the fire area (NFPA 1410).
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 expsoed to a test flame in accordance with ASTM 92, Standard Test Method for Flash and Fire Points by cleveland open cup tester (NFPA1)
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 (NFPA 67)
Flammable Range
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 (NFPA 115)
Flash Point
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 the fire spreads rapidly throughout the space, resulting in full room involvement or total involvement of the compartment or enclosed space (NFPA 921)
Flashover
The movement of heat and smoke from the higher pressure within the fire area toward the lower pressure areas accessible via doors, window openings and roof structures. (NFPA 1410)
Flow Path
A material that will maintain combustion under specific environmental conditions. NFPA 53
Fuel
A fire in which the heat release rate and fire growth are controlled by the characteristics of the fuel there is adequate oxygen available for combustion (NFPA1410)
Fuel-limited fire
The stage of fire development where heat release rate has reached its peak within a compartment (NFPA 1410)
Fully developed stage
The physical state of a substance that has no shape or volume of it’s own and will expand to take the shape and volume of the container or enclosure it occupies (NFPA 921)
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 (roll-over) (NFPA 1410)
Growth stage
The measure of the rate of heat transfer to a surface typically expressed in kilowatts per metre squared (kW/m^2) or Btu/ft^2 (NFPA 268)
Heat Flux
The rates at which heat energy is generated by burning (NFPA 921)
Heat Release Rates
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 act of setting something on fire
Ignition
Minimum temperature a substance should attain in order to ignite under specific test conditions (NFPA 402)
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 (NFPA 1410)
Incipient stage
A burning process in which the fuel is not completely consumed, usually due toa 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 combustible vapour or combustible gas in a mixture of the vapour or gas and gaseous oxidant, above which propagation of flame will occur on contact with an ignition source (NFPA 115)
Lower explosive limit
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 its compounds (NFPA 53)
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 a convection column, thermal updraft or thermal column (NFPA 921)
Plume
A process in which material is decomposed or broken down into simpler molecular compounds by the effects of heat alone, it often precedes combustion (NFPA 921)
Pyrolsis
The combined process of emission, transmission, and absorption of energy travelling by electromagnetic wave propagation (ie - infrared) between a region of higher temperature and a region of lower temperature (NFPA 550)
Radiation
The condition in which unburned fuel (pyrolysate) from the originating fire has accumulated in the ceiling layer to a sufficient concentration (ie - at or above the lower flammable limit) so that it ignites and burns. This can occur without the ignition of, or prior to the ignition of, other fuels seperate from the origin, also known as flameover (NFPA 921)
Roll-over
The airborne solid and liquid particulates and gases evolved when a material undergoes pyrolsis and combustion, together with the quantity of air that is entrained or otherwise mixed into the mass. (NFPA 1404)
Smoke
The attribute of smoke that reflects the stage of burning of a fire and the material that is burning in the fire
Smoke Colour
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 seperate 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 measure by a thermometer or similar instrument
Temperature
A cylindrical area above a fire in which heated air and gasses 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 that indicates great heat in the burning building. It is a precursor to flashover
Turbulent smoke flow
The maximum amount of gaseus fuel that can be present in the air if the air/fuel mixture is to be flammable or explosive.
Upper explosive limit
The weight of an airborne concentration (Vapour or gas) compared to an equa; volume of dry air
Vapour density
A fire in which the heat release rate and fire growth are regulated by the available oxygen within the space. (NFPA 1410)
Ventilation limited fire
The ability of a substance to produce combustible vapours
Volatility
