EX-B01E 2
IM 1F5B2-01E
(2) Shroud
A component part which is so designed that the fastening of joint surfaces cannot be
loosened unless a special tool is used.
(3) Enclosure internal volume
This is indicated by:— the total internal volume of the flameproof enclosure minus
the volume of the internal components essential to equipment functions.
(4) Path length of joint surface
On a joint surface, the length of the shortest path through which flame flows from
the inside to outside of the flameproof enclosure. This definition cannot be applied to
threaded joints.
(5) Gaps between joint surfaces
The physical distance between two mating surfaces, or differences in diameters if the
mating surfaces are cylindrical.
Note: The permissible sizes of gaps between joint surfaces, the path length of a joint
surface and the number of joint threads are determined by such factors as the
enclosure’s internal volume, joint and mating surface construction, and the
explosion classification of the specified gases and vapours.
4. Installation of Flameproof Apparatus
(1) Installation Area
Flameproof apparatus may be installed, in accordance with applicable gases, in a
hazardous area in Zone 1 or 2, where the specified gases are present. Those appara-
tus shall not be installed in a hazardous area in Zone 0.
Note:Hazardous areas are classified in zones based upon the frequency of the appear-
ance and the duration of an explosive gas atmosphere as follows:
Zone 0: An area in which an explosive gas atmosphere is present continuously or is
present for long periods.
Zone 1: An area in which an explosive gas atmosphere is likely to occur in normal
operation.
Zone 2: An area in which an explosive gas atmosphere is not likely to occur in normal
operation and if it does occur it will exist for a short period only.
(2) Environmental Conditions
The standard environmental condition for the installation of flameproof apparatus is
limited to an ambient temperature range from -20∞ to +40∞C (for products certified
under Technical Criteria). However, some field-mounted instruments may be
certified at an ambient temperature up to +60∞C as indicated on the instrument
nameplates. If the flameproof apparatus are exposed to direct sunshine or radiant heat
from plant facilities, appropriate thermal protection measures shall be taken.
5. External Wiring for Flameproof Apparatus
Flameproof apparatus require cable wiring or flameproof metal conduits for their
electrical connections. For cable wiring, cable glands (cable entry devices for flameproof
type) to wiring connections shall be attached. For metal conduits, attach sealing fittings
as close to wiring connections as possible and completely seal the apparatus. All non-
live metal parts such as the enclosure shall be securely grounded. For details, see the
“USER’S GUIDELINES for Electrical Installations for Explosive Gas Atmospheres in
General Industry,” published in 1994.
