Assertion: sidemount diver | /r/CapableOf | use pure air
Facets:
value: as a reference gas
type: PURPOSE
Source sentences:
text: Most Nitrox divers use pure air as a reference gas, as its FO2 is unequivocal and, being closer to the FO2 of the mixture being analyzed, the margin for error is less than it would be if using pure oxygen as a reference gas.