For the benefit of our readers who may become involved with fire terminology and who may want clarification of expressions used, we list below internationally accepted definitions of some of the more common terms. These may be found in the International Standard ISO 3261 (1st Edition, 1975).
Calorific potential: The energy which a unit mass of material or element of building construction (component or structure) is capable of releasing by complete combustion.
Charring: The formation by heating of more or less pure carbon during pyrolysis or incomplete combustion.
Combustion: Reaction of a substance with oxygen (apart from exceptional cases, the concentrations of oxygen to be considered do not exceed those normally found in air) with release of heat generally accompanies by flaming and/or glowing and/or emission of smoke.
Fire behaviour: All the physical and chemical changes which take place when materials and elements of building construction (component or structure) are exposed to the destructive action of fire.
Fire integrity: The ability of a separating element of building construction, when exposed to fire on one side, to prevent the passage through it of flames and hot gases or the occurrence of flames on the unexposed side.
Fire load: The calorific potential, expressed S1 units, of the combustible materials contained in a space, including the facings of the walls, partitions, floors and ceilings.
Fire load density: The fire load per unit floor area.
Fire resistance: The ability of an element of building construction (component or structure) to fulfil for a stated period of time the required stability, integrity and/or thermal insulation specified in the standard fire-resistance test (see ISO 834, Fire-resistance Tests on Elements of Building Construction).
Fire retardant: The quality of a substance of suppressing, reducing or delaying markedly the combustion of certain materials.
Fire stability: The ability of an element of building construction, load-bearing or non-load-bearing, to resist collapse when submitted to a fire.
Flame (noun): (Zone of) combustion in the gaseous phase, with emission of light (does not include 'cold flames', which will be defined in a future International Standard).
Flame (verb): To undergo combustion in the gaseous phase with the emission of light.
Flame retardance: The property of a material or a treatment applied to a material of retarding the propagation of flame.
Flaming (noun): The process of continuation of flames after their first appearance.
Flammable: Capable of undergoing combustion in the gaseous phase with emission of light during or after the application of an igniting source.
Flash over: The transition to a state of total surface involvement in a fire of combustible materials within a compartment.
Flash point: The temperature at which, under defined conditions, the concentration of gases emitted from a combustible solid or liquid is such that the lower flammability limit is reached. (This term will be subject to further studies when the Standard is revised).
Gasification: The transformation of a material, partially or wholly, to the gaseous state.
Glowing: The combustion of a material without flame but with emission of visible light from the combustion zone surface.
Non-flammable: Not capable of undergoing combustion in the gaseous phase during or after the application of an igniting source.
Pyrolysis: Irreversible chemical decomposition due to an increase in temperature without oxidation.
Pyrophoric material: A material capable of rapid spontaneous combustion when brought in contact with air.
Rate of heat release: The amount of heat released by a burning body in unit time.
Rate of spread of flame: For a gas: the rate of spread of flame front, in the gas. For a solid: the rate of spread of the flame on the surface of a solid.
Reaction to fire: The response of a material in contributing by its own decomposition to a fire to which it is exposed.
Self-extinguishing: It is not possible to provide a standard definition of this term in view of the present state of knowledge on the properties it covers and of the type of materials to which it can be applied. (Term deprecated since it may convey a false sense of security).
Smouldering : The combustion of a material without light and often evidenced by smoke.
Spontaneous combustion: Combustion starting at normal temperature without externally applied heat. (This term will be subject to further studies when the Internal Standard is revised).
Thermal insulation: The ability of a separating element of building construction to prevent excessive transmission of heat.
Reference: Fire Protection Association of Southern Africa
© Technews Publishing (Pty) Ltd. | All Rights Reserved.
printer friendly version