Originally Posted by Sleddgracer
propane flows to the ground when it leaks, CNG rises when it leaks so CNG must weigh less per gal than Propane - perhaps tanks filled with helium would lower GVW?
Your propane tank is filled with LIQUEFIED petroleum gas. The liquid boils off and provides the gas that you burn. LPG tanks will see 100-300psi depending on temperature.
CNG tanks are filled with COMPRESSED natural gas. It is compressed to over 3000 psi but still in a gaseous state.
Helium tanks make me talk funny....