Gaseous fuels whose combustion characteristics are in large measure similar, i.e. that have similar Wobbe numbers, which make them interchangeable, form a family of gases. The first family comprises town gas (hydrogen-rich gaseous fuels); the second family comprises natural gases, gases associated with petroleum and gases interchangeable with these; and the third family comprises liquefied petroleum gases (propane and butane).
Country... Gas family... Wobbe index (gross) in... Supply pressure in mbar...