Shenhai Explosion-Proof
The average molecular weight of air is 29, making gases with a molecular weight greater than 29 heavier than air.
Combustible organic gases heavier than air include propane, butane, propylene, butadiene, acetylene, cyclopropane, dimethyl ether, and ethylene oxide. Inorganic combustible gases heavier than air encompass hydrogen sulfide, phosphine, and silane.