− 30 −
Glossary
Zero adjustment:
Zero-point setting in pure air (21 vol% adjustment for Oxygen)
Explosion-proof:
A structure applied to electrical equipment to prevent the equipment from igniting
the surrounding explosive atmosphere as the source of ignition.
Intrinsically safe design:
A structure whose inability to ignite explosive gases with a spark of
electricity or a hot section generated in normal time or an accident has been confirmed in fire and other
tests.
Flame proof type:
A type of protection in which the parts can ignite an explosive atmosphere are
to be placed in an enclosure, which can withstand the pressure developed during internal explosion of
an explosive mixture, and which prevents the transmission of the explosion to the explosive atmosphere
surrounding the enclosure.
Non hazardous area:
A place where there is no possibility that an explosive gas will mix with the air
under ordinary or abnormal circumstances and reach the explosion limit.
%LEL:
Concentrations of combustible gases given in terms of percent of the lower explosive limit.
vol %:
Gas concentrations given in terms of percent of cubic volume.
(Partly cited from the Industrial Gas Detectors Monitor Association, Glossary of Gas Detector Alarms, and
Glossary of Detection Tube Type Gas Measuring Instrument)
12. Glossary
