Fire Terms

 

Fire:

            The process of combustion during which flammable materials burn producing heat, accompanied by flames, smoke or toxic gasses, or any combination of these.

            The common misconception is that fire burns the actual piece of wood or fuel. It is the gasses given off by an object that actually burn.

            Heat causes objects to give off these flammable gasses, and when the gasses reach their ignition temperature you see the light given off during the oxidation process, known as fire.

            Fire itself generates more heat to the object and thus an endless cycle begins until all of the gasses have been exhausted from an object. Then the remaining particles or ash are what is left.

Flammable:

Capable of being readily ignited and burning in air.

Combustion:

An exothermic reaction of a substance with oxygen, causing the release of heat and generally accompanied by flames, or glowing, and/or the emission of gasses or smoke.

Combustible Material:

Any material in a building or structure that is combustible as determined by a Combustibility Test for materials.

Fire Hazard:

The potential for any item to give rise to a fire when exposed to an ignition source. Potential for injury and/or damage from fire

Fire compartment Enclosed space, which may be subdivided, separated from adjoining spaces within the building by elements of construction having a specified fire resistance

Fire exposure Extent to which persons, animals or items are subjected to the conditions created by fire

Fire resistance Ability of an item to fulfil for a stated period of time the required stability and/or integrity and/or thermal insulation, and/or other expected duty specified in a standard fire-resistance test

Flash-over Transition to a state of total surface involvement in a fire of combustible materials within an enclosure

Fire Load:

The heat energy potential of the entire combustible contents of a building space, including furnishings, built in and removable items, and partitions, floors and ceilings, normally expressed as mega joules (MJ).

Fire Load Density:

The fire load divided by the floor area, expressed in joules per square metre (J/m2).

Fire Integrity:

The ability of a constructed element, when exposed to a fire on one side, to prevent the passage of flames and hot gasses or the occurrence of flames on the unexposed side, for a stated period of time determined in a standard fire resistance test.

Fire Isolation:

The isolation of one part of a building by a fire resistant method of construction.


Fire Limit State:

A limit state of collapse or loss of structural integrity due to fire.

Fire safety;

An essential part of any building fire safety system (probably the most important part) is training and education of the occupants in matters of fire safety.

At its most basic, is based upon the principle of keeping fuel sources and ignition sources separate.

Fire Resistance:

The ability of an element of construction, component or structure to fulfil, for a stated period of time, the required structural adequacy, integrity, thermal insulation or other expected duty, during exposure to a standard fire resistance test.

Exothermic and Endothermic

An exothermic process is one that gives off heat i.e. heat is transferred to the surroundings. Many chemical reactions release energy in the form of heat, light, or sound. Exothermic reactions may occur spontaneously and may even be explosive.

An endothermic process is one in which heat has to be supplied to the system from the surroundings. An endothermic reaction must absorb energy in order to proceed and cannot occur spontaneously. Work must be done in order to get these reactions to occur. When endothermic reactions absorb energy, a temperature drop is measured during the reaction.

A thermoneutral process is one that neither requires heat from the surroundings nor gives off energy to the surroundings.

These terms are usually applied to chemical reactions. A chemical reaction can only be one of these three terms at once. A reaction that is exothermic will be endothermic if run backward and vice-versa.

 

Exothermic processes

Endothermic processes

making ice cubes

melting ice cubes

formation of snow in clouds

conversion of frost to water vapour

condensation of rain from water vapour

evaporation of water

a candle flame

baking bread

rusting iron

cooking an egg

combining atoms to make a molecule in the gas phase

splitting a gas molecule apart

mixing water and strong acids or with calcium chloride

mixing water and ammonium nitrate

nuclear fission

 

 

Adiabatic

A term used to describe a combustion reaction in which all heat generated is retained in the products of combustion. Adiabatic flame temperature is the theoretical temperature that would be attained by the products of combustion provided the entire chemical energy of the fuel, the sensible heat content of the fuel and combustion above the datum temperature were transferred to the products of combustion. This assumes that there is no heat loss to surroundings and no dissociation.

Dissociation

is a reaction involving the breakdown of chemical compounds. In the case of combustion, these are water vapour and carbon dioxide.

Stoichiometric

describes the correct mixture of ingredients in a chemical reaction. After the reaction is over, no surplus ingredients will be left. In combustion, the stoichiometric ratio also is called correct, ideal or perfect ratio.

Pyrolysis

That part of the irreversible chemical decomposition caused solely by a rise in temperature. This decomposition can provide a buffer between the burning surface and the material beneath

 

Australian Fire Standards (Parts of AS 1530)

AS 1530.1-1994 : 
Methods for fire tests on building materials, components and structures - Combustibility test for materials

AS 1530.2-1993 : 
Methods for fire tests on building materials, components and structures - Test for flammability of materials

AS/NZS 1530.3:1999 : 
Methods for fire tests on building materials, components and structures - Simultaneous determination of ignitability, flame propagation, heat release and smoke release

AS 1530.4-2005 : 
Methods for fire tests on building materials, components and structures - Fire-resistance test of elements of construction

AS 1530.7-2007 : 
Methods for fire tests on building materials, components and structures - Smoke control assemblies - Ambient and medium temperature leakage test procedure

 

Building Code of Australia (BCA)

Volume 1 SECTION C FIRE RESISTANCE

Part C1 Fire Resistance and Stability

Part C2 Compartmentation and Separation

Part C3 Protection of Openings

Specifications

BCA Fire Terms refer to Part A1, A1.1  Definitions