3.6
gap of flameproof joint
i
distance between the corresponding surfaces of a flameproof joint when the electrical
apparatus enclosure has been assembled
NOTE For cylindrical surfaces, forming cylindrical joints, the gap is the difference between the diameters of the
bore and the cylindrical component.
3.7
maximum experimental safe gap (for an explosive mixture)
MESG
maximum gap of a joint of 25 mm in width which prevents any transmission of an explosion
during 10 tests made under the conditions specified in IEC 60079-1-1
3.8
shaft
part of circular cross-section used for the transmission of rotary movement
3.9
operating rod
part used for the transmission of control movements which may be rotary or linear or a
combination of the two
3.10
pressure-piling
results of an ignition, in a compartment or subdivision of an enclosure, of a gas mixture precompressed,
for example, due to a primary ignition in another compartment or subdivision
3.11
quick-acting door or cover
door or cover provided with a device which permits opening or closing by a simple operation,
such as the movement of a lever or the rotation of a wheel. The device is arranged so that the
operation has two stages:
– one for locking or unlocking;
– another for opening or closing
3.12
door or cover fixed by threaded fasteners
door or cover, the opening or closing of which requires the manipulation of one or more
threaded fasteners (screws, studs, bolts or nuts)
3.13
threaded door or cover
door or cover which is assembled to a flameproof enclosure by a threaded flameproof joint
3.14
breathing device
integral or separable part of a flameproof enclosure designed to permit exchange between the
atmosphere inside the enclosure and the surrounding atmosphere
3.15
draining device
integral or separable part of a flameproof enclosure designed to permit water formed by
condensation to escape from the enclosure