Substance that exists exclusively in the gaseous state at normal atmospheric pressure and temperature and is capable of igniting and burning when mixed with air (oxygen) in the proper proportion and subjected to a source of ignition.
Source: API RP 98, Personal Protective Equipment Selection for Oil Spill Responders, First Edition, August 2013. Global Standards
Flammable Gas (Gas Properties)
Gas or vapour which, when mixed with air in a certain proportion, will form an explosive atmosphere.
NOTE For the purposes of this standard, the term “flammable gas” includes flammable vapours.
Source: IEC 60079-29-1, Explosive atmospheres – Part 29-1: Gas detectors – Performance requirements of detectors for flammable gases. Global Standards
Flammable Gas (or Vapour)
Gas or vapour which, when mixed with air in certain proportions, will form an explosive gas atmosphere.
Source: IEC 61892-7, Mobile and fixed offshore units – Electrical installations – Part 7: Hazardous areas. Global Standards