3 Chapter this book.
.
Hazardous area classification
The British Standard divides the risk associated with inflammable gases
and vapours into three classes zones.
Flammable and explosive installations are found the petroleum
and chemical industries, which are classified group industries. All certified flameproof enclosures will be
marked Ex, indicating that they are suitable for potentially explosive
situations, EEx, where equipment certified the harmonized
European Standard.
● Zone the most hazardous, and defined zone area in
which explosive gas–air mixture continuously present pres-
ent for long periods. (‘Long periods’ usually taken mean that the
gas–air mixture will present for longer than 1000h per year.
Where the cable laid underground, must protected PVC
sheath and laid depth not less than 500mm.
● PVC armoured cables terminated into accessories with approved
flameproof glands any other wiring system which approved
by the British Standard. Petrol
filling pumps must wired and controlled flameproof equipment
to meet the requirements the Petroleum Regulation Act 1928 and 1936
and any local licensing laws concerning the keeping and dispensing of
petroleum spirit. All the equipment used flameproof instal-
lation must carry the appropriate markings, shown Fig.Statutory regulations and codes practice
271
a hazardous area must flameproof fittings using appropriate
method, such as:
● PVC cables encased solid drawn heavy-gauge screwed steel con-
duit terminated approved enclosures having wide flanges and
bolted covers. These have longer gland thread than normal
MICC glands the type shown Fig.5, if
the integrity the wiring system maintained.
● Mineral insulated cables terminated into accessories with approved
flameproof glands.5
Flameproof equipment markings. 6. Mining
is classified group and receives special consideration from the Mining
Regulations because the extreme hazards working underground. 13.)
X
FIGURE 13
