NF C23-560-2-2005
可燃气体的检测和测量用电气设备.第2部分:指示空气中甲烷的体积百分率最大为5%的I类设备的性能要求
Electrical apparatus for the detection and measurement of flammable gases - Part 2 : performance requirements for group I apparatus indicating a volume fraction up to 5 % methane in air.