Introduction to Fire Safety Management

Ventilation/fume cupboards
– in certain operations 
(e.g. solvent-based spraying operations or decanting 
of fl ammable liquids) booths or cabinets are required 
to control the build-up of fl ammable vapours. In such 
instances the airfl 
ow rate into all openings in the 
enclosure should be suffi cient (about 1 m/s) to prevent 
vapours entering the work area. These ventilation booths, 
cabinets and other enclosed equipment are generally 
designed to ensure that the vapours are kept below 25% 
of their LEL.
As the outcome or failure of any ventilation system 
or part of the system may result in a build-up in vapour 
concentrations with the potential for both fi re and 
explosion, the system must be provided with an alarm 
system to provide warning.
There are also a number of storage systems that 
are combined with booths and cabinets which use LEV 
for vapour control. Regardless of the system used each 
must be subject to rigorous maintenance testing and 
examination regimes to ensure that fl ammable vapours 
are controlled.
Any electrical system used as part of the ventila-
tion or extraction systems must meet rigid electrical 
standards and as in the case of all such equipment 
be intrinsically safe. As discussed earlier, classifying 
hazardous or potentially explosive atmospheres is not 
only a legal requirement under DSEAR but has been 
widely used to determine the extent of hazardous zones 
created by fl ammable concentrations of vapours.
Over recent years the process of classifying hazard-
ous areas in such a way has been extended from its 
initial purpose of selecting fi xed electrical equipment 
for use in the area, to helping to identify and eliminate 
potential ignition sources, including portable electrical 
equipment, vehicles, hot surfaces, etc. from fl ammable 
atmospheres.
Wind
direction