Glossary of fire terms and definitions

ISO glossary of fire terms and definitions (mostly ISO TC 92).

Approvals Body – organisation responsible for approving the fire safety aspects of a building (UK examples are Local Authority Building Control Officers, approved Inspectors, and the Fire Authority. The authority having jurisdiction (AHJ) in the USA).

Available Safe Egress (ASET) – calculated time available between ignition of a fire and the time at which tenability criteria are exceeded in a specified space.

Area Burning Rate (m2 /s)– area of material burned per unit time under specified conditions.

Backdraft – a rapid deflagration following the introduction of oxygen into a fire compartment filled with accumulated unburnt fuel.
Burning Behaviour – all the physical and/or chemical changes that take place when a material or product is exposed to a specified ignition source.

Char (noun) – carbonaceous residue during pyrolysis or incomplete combustion

Chimney Effect – upward thrust of smoke and hot gases by convection currents confined within a vertical enclosure

Combustible – capable of undergoing combustion

Combustion – reaction of a substance with oxygen with release of heat generally accompanied by flaming and/or glowing and/or emission of smoke

Deflagration – an explosion propagating at subsonic velocity

Deterministic study – methodology, based on physical relationships derived from scientific theories and empirical results, that for a given set of initial conditions will always produce the same outcome

Ease of Ignition – the ease with which a material can be ignited under specified test conditions

Enclosure – space defined by boundary elements (on all sides)

Escape Time – calculated time from ignition until the time at which all the occupants of a specified part of a building are able to reach a place of safety

Evacuation Time – interval between the time of a warning of fire being transmitted to the occupants and the time at which all of the occupants are able to reach a place of safety

Fire – a process of combustion characterised by the emission of heat accompanied by smoke and/or flame

Fire Behaviour – all the physical and chemical changes which take place when materials and elements of building construction are exposed to the destructive action of fire

Fire Compartment – an enclosed space in a building that is separated from all other parts of the building by enclosing construction having a specified period of fire resistance, within which a fire can be contained (or from which a fire can be excluded), without spreading to (or from) another part of the building

Fire Hazard – the potential for loss of life (or injury) and/or damage to property by fire

Fire Load (J) – the calorific potential, expressed in SI units, of the combustible materials contained in a space, including the facings of the walls, partitions and ceilings

Fire Load Density (J/m2) – the fire load per unit floor area

Fire Resistance (min) – the ability of an element of building construction to fulfill for a stated period of time the required stability, integrity and/or thermal insulation specified in the standard fire resistance test

Fire Resistance (separating element) – the ability of an element to provide, for a stated period of time, simultaneous integrity and thermal insulation in the standard fire resistance test (see ISO 834)

Fire Retardant – the quality of a substance of suppressing, reducing or delaying markedly the combustion of certain materials

Fire Risk – probability of fire causing a loss of life (or injury) and/or damage to property

Fire Safety Engineer – person suitably qualified and experienced in fire safety engineering

Fire Scenario – set of circumstances, chosen as an example, that defines the development of fire and the spread of combustion products throughout a building or part of a building

Flame – (zone of) combustion in the gaseous phase, with the emission of light. Does not include ‘cold flames’

Flame Front – the boundary of the combustion zone in the gaseous phase at the surface of a material

Flame Resistance – deprecated term

Flame Retardance – the property of a material or a treatment applied to a material of retarding the propagation of flame

Flame Retardant (noun) – a substance added, or a treatment applied, to a material in order to suppress, significantly reduce or delay the propagation of flame

Flame Retarded – treated with a flame retardant

Flame Spread – propagation of a flame front

Flame Spread
Rate; Rate of Flame Spread (m/s)
– distance travelled by a flame
front during its propagation, per unit time, under specified test conditions

Flaming (noun) – the process of continuation of flames after their first appearance

Flammability – the ability of a material or product to burn with a flame under specified test conditions

Flammable – capable of undergoing combustion in the gaseous phase with emission of light during or after the application of igniting source

Flash-Over – the rapid transition to a state of total surface involvement in a fire of combustible materials within a compartment

Flash Point; Flash Temperature (°C) – 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

Fully Developed Fire – the state of total involvement of combustible materials in a fire

Heat of Combustion; Calorific Potential (J/kg) – the energy which a unit mass of material or element of building construction is capable
of releasing by complete combustion

Heat Release Rate; Rate of Heat Release – the amount of heat released by a burning body in unit time

Ignitability – the measure of the ease with which a specimen can be ignited due to the influence of an external heat source, under specified test conditions

Ignition Source – an applied source of heat which is used to ignite combustible materials

Ignition Temperature – the lowest temperature at which a solid can ignite directly of by the evolution of combustible gas which will ignite and sustain the combustion process

Ignition Time – deprecated term

Inflammability; Inflammable – deprecated terms

Linear Burning Rate (m/s) – length of material burned per unit time under specified test conditions

Mass Burning Rate (kg/s) – mass of material burned per unit time under specified test conditions

Means of Escape – means whereby safe routes are provided for persons to travel from any point in a building to a place of safety

Melt Drip – falling droplets of molten material either burning or not

Melting Behaviour – phenomena accompanying the softening of a material under the influence of heat (including shrinking, dripping, burning of molten material, etc.)

Minimum Ignition Time (s) – minimum time of exposure of a material to an ignition source to obtain sustained combustion under specified test conditions

Net Calorific Value – the quantity of heat released by the complete combustion of a unit mass of the material, the produced
water being in the vapour phase

Non-Combustible – not capable of undergoing combustion under specified test conditions

Non-Flammable – not capable of burning with a flame under specified test conditions

Opacity of Smoke – the ratio (I/T) of incident luminous flux (I) to transmitted luminous flux (T) through smoke under specified test conditions

Optical Density of Smoke [lg(I/T)] – a measure of the degree of opacity usually expressed as the common logarithm of the ratio of the incident light intensity to the transmitted light intensity

Oxygen Index (O1) – the minimum concentration of oxygen and nitrogen that will just support flaming combustion of a material under specified test conditions

Phased Evacuation – process by which a limited number of floors (usually the fire floor and the storey above) is evacuated
initially and the remaining floors are evacuated when necessary

Place of Safety – predetermined place in which persons are in no immediate danger from the effects of fire (may be inside or outside
the building depending on the evacuation strategy)

Pre-movement Time – time interval between the warning of fire being given (by an alarm or by direct sight of smoke or fire) and the
first move being made towards an exit

Probabilistic Risk Assessment – methodology to determine statistically the probability and outcome of events

Products of Combustion – use Fire Effluent

Pyrolysis – irreversible chemical decomposition of a material 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 Burning; Burning Rate – deprecated terms

Reaction to Fire – the response of a material in contributing by its own decomposition to a fire to which it is exposed

Self-Extinguishing – term deprecated since it may convey a false sense of security

Self-Heating – an exothermic reaction within a material resulting in a rise in temperature in the material

Self-Ignition – ignition resulting from self-heating

Self-Propagation of Flame – the propagation of a flame front after removal of applied heat source

Smoke – a visible suspension in air of solid and/or liquid particles resulting from incomplete combustion

Smoke Obscuration – the reduction in luminous intensity due to passage through smoke

Smouldering – the combustion of a material without light and often evidenced by smoke

Soot – a powdered residue of amorphous carbon formed during incomplete combustion

Specific Optical Density of Smoke – a measure of the smoke produced by a specimen of a material or a product, taking into account the optical density and factors characteristic of the specified test method. NB Specific optical density is a dimensionless number

Spontaneous Combustion – combustion starting at normal temperature without externally applied heat

Spontaneous Ignition Temperature (°C) – the minimum temperature at which ignition is obtained by heating, under specified test conditions
in the absence of any additional ignition source (also called auto-ignition temperature)

Temperature-Time Curve (standardised) – the time-related variation of temperature measured during experimental tests of fire resistance. ISO 834 expresses this as follows

T – To = 345 log10 (8t + 1)
where t is time (min)
T is the furnace temperature (°C) at time t
To is the initial furnace temperature (°C)

Tenability Criteria – maximum exposure to hazards from a fire that can be tolerated without causing incapacitation

Thermal Radiation – transfer of thermal energy by electromagnetic waves

Travel Distance – actual distance that needs to be travelled by a person from any point within a building to the nearest exit, having regard to the layout of walls, partitions and fittings

Travel Time – time needed, once movement has begun, for all the occupants of a specified part of a building to move to a place of safety

ISO Documents

  • ISO 834-1:1999, Fire Resistance Tests – Elements of Building Construction – Part 1: General Requirements
  • ISO 1716: 1973 Building Materials – Determination of Calorific Potential
  • ISO 9705: 1993 Fire Tests – Full Scale Room Teat for Surface Products
  • ISO/TR 10158:1991, Principles and Rationale Underlying Calculation Methods in Relation to Fire Resistance of Structural Elements
  • ISO/TR 11696-1: 1999, Uses of Reaction to Fire Test Results – Part 1: Application of Test Results to Predict Fire Performance of Internal Linings and Building Products, 1999
  • ISO/TR 11692-2: 1999, Uses of Reaction to Fire Test Results – Part 2: Fire Hazard Assessment of Construction Products, 1999
  • ISO/TR 12470:1998, Fire Resistance Tests – Guidance on the Application and Extension of Results
  • ISO/TR 13387-1, Fire Safety Engineering – Part 1: Application of the Fire Performance Concepts to Design Objectives
  • ISO/TR 13387-2, Fire Safety Engineering – Part 2: Design Fire Scenarios and Design Fires
  • ISO/TR 13387-3, Fire Safety Engineering – Part 3: Assessment and Verification of Mathematical Fire Models
  • ISO/TR 13387-4, Fire Safety Engineering – Part 4: Initiation and Development of Fire and Generation of Fire Effluents
  • ISO/TR 13387-5, Fire Safety Engineering – Part 5: Movement of Fire Effluents
  • ISO/TR 13387-6, Fire Safety Engineering – Part 6: Detection, Activation and Suppression
  • ISO/TR 13387-7, Fire Safety Engineering – Part 7: Occupant Behaviour, Location and Condition
  • ISO/TR 13387-8, Fire Safety Engineering – Part 8:
  • ISO/DTR 15655, Fire Resistance – Tests for Thermo-Physical and Mechanical Properties of Structural Materials at Elevated Temperatures for Fire Engineering
  • ISO/DTR 15656, Guide for Evaluating the Capability of Calculation Models for Structural Fire Behaviour