3 Terms and definitions
For the purposes of this document, the following terms and definitions, in addition to those
given in IEC 60079-0, apply.
3.1
flameproof enclosure “d”
enclosure in which the parts which can ignite an explosive atmosphere are placed and which
can withstand the pressure developed during an internal explosion of an explosive mixture, and
which prevents the transmission of the explosion to the explosive atmosphere surrounding the
enclosure
3.2
volume
total internal volume of the enclosure. However, for enclosures in which the contents are
essential in service, the volume to be considered is the remaining free volume
NOTE For luminaires, the volume is determined without lamps fitted.
3.3
flameproof joint
place where the corresponding surfaces of two parts of an enclosure, or the conjunction of
enclosures, come together, , and which prevents the transmission of an internal explosion to
the explosive atmosphere surrounding the enclosure
3.4
width of flameproof joint
Ls
hortest path through a flameproof joint from the inside to the outside of an enclosure
3.5
distance
l
shortest path through a flameproof joint, when the width of the joint L is interrupted by holes
intended for the passage of fasteners for assembling the parts of the flameproof enclosure