HAZARDOUS LOCATION:

An area where the possibility of explosion and fire is created by the presence of flammable gases, vapors, dusts, fibers or filings.

DIVISION 1

Division 1 in the normal situation; the hazard would be expected to be present in everyday production operations or during frequent repair and maintenance activity.

DIVISION 2

Division 2 in the abnormal situation; material is expected to be confined within closed containers or closed systems and will be present only through accidental rupture, breakage or unusual faulty operation.

CLASS I

Those areas in which flammable gases or vapors may be present in the air in sufficient quantities to be explosive or ignitable.

CLASS II

Those areas made hazardous by the presence of combustible dust.

CLASS III

Those areas in which there are easily ignitable fibers or filings present, due to type of material being handled, stored or processed.

GROUPS

The gases and vapors of
Class I locations are broken
into four groups by the
codes A, B, C and D.
These materials are grouped according to the ignition temperature of the substance,
its explosion pressure and other flammable characteristics.

Group A

Group B

Group C

Group D

Acetylene

Hydrogen

Ethyl-Ether, Ethylene, Cycle Propane

Gasoline, Hexane, Naphtha, Benzene, Butane, Propane, Alcohol, Lacquer Solvent, Vapors, Natural Gas

Class II - dust locations -
groups E, F & G. These
groups are classified according
to the ignition temperature
and the conductivity of the
hazardous substance.

Group E

Group F

Group G

Metal Dust

Carbon Black, Coal, Coke Dust

Flour, Starch, Grain Dust

OPERATING

Maximum

Temperature

Temp

TEMPERATURE

CODES

Degrees C

Degrees F

Code

450

842

T1

300

572

T2

280

536

T2A

260

500

T2B

230

446

T2C

215

419

T2D

200

392

T3

180

356

T3A

165

329

T3B

160

320

T3C

135

275

T4

120

248

T4A

100

212

T5

85

185

T6