Definitions
The lowest temperature which
sufficient vapour given off from
a flammable substance form an
explosive gas–air mixture called the
flashpoint.
Definition
They define hazardous area ‘any
place which explosive atmos-
phere may occur such quantity as
to require special precautions pro-
tect the safety workers’. Flameproof electrical equipment constructed that can withstand
an internal explosion the gas for which certified, and prevent any
spark flame resulting from that explosion leaking out and igniting
the surrounding atmosphere. Clearly these regulations affect the petroleum
industry, but they also apply petrol filling stations. 13. Since those early days many national and inter-
national standards, well codes practice, have been published to
inform the manufacture, installation and maintenance electrical equip-
ment all hazardous areas.
They define hazardous area ‘any place which explosive atmo-
sphere may occur such quantity require special precautions pro-
tect the safety workers’. liquid which safe normal temperatures will
require special consideration heated flashpoint. The lowest temperature which sufficient vapour is
given off from flammable substance form explosive gas–air mixture
is called the flashpoint.
(a) (b) (c) (d)
. All access and
connection points have wide machined flanges which damp the flame in
its passage across the flange. Above and below this level concentration the mix
will not explode.
An area which explosive gas–air
mixture present called hazard-
ous area, defined the British
Standards, and any electrical appara-
tus equipment within hazardous
area must classified flameproof.4
Flameproof fittings: (a) flameproof distribution board; (b) flameproof rectangular junction box; (c)
double-pole switch; (d) flameproof inspection bend.Basic Electrical Installation Work
270
Hazardous area installations
The British Standards concerned with hazardous areas were first published
in the 1920s and were concerned with the connection electrical apparatus
in the mining industry. This achieved manufacturing flame-
proof equipment robust standard construction. area which an
explosive gas–air mixture present called hazardous area, defined
by the British Standards, and any electrical apparatus equipment within
a hazardous area must classified flameproof.
The relevant British Standards for Electrical Apparatus for Potentially
Explosive Atmospheres are 5345, 60079 and 50014: 1998.
Most flammable liquids only form explosive mixture between certain
concentration limits.4. Flanged surfaces are firmly bolted together
with many recessed bolts, shown Fig. Wiring systems within
FIGURE 13
