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8. Definition of words
%LEL
When define the Lower Explosion Limit of combustible gas as 100%.
Methane
：
100%LEL = 5.0vol%
Iso-butane
：
100%LEL = 1.8vol%
Vol%
This is the unit shown by percentage for how much a special material (or gas) in a volume is
occupied in that volume.
Combustible gas
The lower limit of Explosive Limit (Explosive limit when mixed with air) is to be below 10%.
The difference between upper and lower limits is to be above 20%.
HC gas
General name of hydrocarbon.
in Air
The atmosphere of –10
〜
+40 , below 90%RH in an atmospheric pressure (0113hPa)
Hang-up phenomenon
This is the phenomenon to show slightly higher reading than the actual one by the influence
residual gas for some while though fresh air is supplied after high density gas was sucked
into instrument.
Oxygen deficiency
Phenomenon that may cause human health disorder.
