Introduction to Fire Safety Management

Principles of fi re and explosion
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capable of producing more vapour that once ignited 
is able to sustain the combustion cycle
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Spontaneous ignition or auto-ignition tempera-
ture
is the lowest temperature at which a substance 
will ignite spontaneously without any other igni-
tion source. A spark is not necessary for ignition 
when a fl ammable vapour reaches its autoignition 
temperature.
Some materials have a spontaneous ignition tem-
perature that is so low that they are capable of ignit-
ing under normal conditions at room temperature. 
One such material is linseed oil which as an organic 
material reacts with oxygen at room temperature; 
this is called oxidisation.
The lower the fi re-/fl ashpoints or autoignition tempera-
tures, the more likely will be the chemicals’ involvement 
in supporting a fi re at/near ambient or room tempera-
tures and the likelihood that the combustion process will 
continue and produce a fi re condition.
Also included on MSDS is the following information:
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Vapour pressure
is the pressure of a vapour given 
off by (evaporated from) a liquid or solid, caused 
by atoms or molecules continuously escaping from 
its surface. Vapour pressure is measured in units 
of pressure such as pascals. The higher the vapour 
pressure of a substance at any given temperature, 
the more volatile the substance is and therefore the 
more likely it will be that vapour will be ‘given off’. 
Figure 7.10 shows a small region of a liquid near its 
surface.
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Vapour density
is the density of a gas, expressed 
as the mass of a given volume of the gas divided 
by the mass of an equal volume of a reference gas 
(such as hydrogen or air) at the same temperature 
and pressure.
Also included on the MSDS will be informa-
tion relating to the