THINK DETAILS FOR FLAMMABILITY

                          Is the flash point < ambient temperature?

The so-called “do-nothing” action in reality means a great deal and involves monitoring the situation as it evolves during the incident.

The flash point of a liquid is the lowest temperature of a material at which vapours over its liquid surface will ignite and burn when exposed to a specified ignition source.  As a rule of thumb, a liquid which has a flash point close to the ambient temperature, or has a lower flash point relative to the ambient temperature, will be easily ignited by a spark or naked flame.  Any liquid with a flash point < 21^oC can be considered highly flammable.  There must also be sufficient oxygen and vapours available in the vapour-air mixture to support and sustain combustion.  The minimum concentration of a vapour that will ignite and propagate a flame is the Lower Flammable Limit (LFL).  The flash point is theoretically the temperature at atmospheric pressure to which a liquid must be raised to produce a vapour over its surface equivalent to its LFL.  The words flammable and explosive are also used interchangeably such that LFL values typically equal LEL.  Similar to explosive gaseous/vapour clouds, the same rule of thumb applies, i.e. care must be taken when the concentration of the vapour exceeds 10% of the LFL (refer to explosivity - Think Detail  - Monitoring)