NF C23-558:1992 Electrical apparatus for the detection and measurement of combustible gases. Performance requirements for group II apparatus indicating up to 100 per cent (V/V) gas.
2008NF C23-579-29-1:2008 Explosive atmospheres - Part 29-1 : gas detectors - Performance requirements of detectors for flammable gases.
2005NF C23-560-5:2005 Electrical apparatus for the detection and measurement of flammable gases - Part 5 : performance requirements for group II apparatus indicating a volume fraction up to 100 % gas.
1992NF C23-558:1992 Electrical apparatus for the detection and measurement of combustible gases. Performance requirements for group II apparatus indicating up to 100 per cent (V/V) gas.