The vast majority of the liquefied petroleum gas (LP-gas) sold to the motorhome industry is propane (C3H8); however, I am told that butane (C4H10) is still available in certain parts of the extreme South and in Mexico. Huge differences exist between these fuels, and motorhome owners should make certain that they are indeed getting propane when filling their tank in those areas.
Below is a chart that illustrates some of the differences between propane and butane.
(This is the temperature where vapor pressure starts)
|Weight, Per Gallon, at 60Â°F||4.24#||Â||4.81#Â|
|Btus Per Pound of Liquid (This may vary slightly)||21,591||Â||21,221|
|Air-Fuel ratio (Peak)
(This tells us the fuels aren’t interchangeable)
|Range of Combustion, Fuel Percentage
(This is the percent of fuel in the air-fuel ratio at which ignition occurs)
|2.4 to 9.6%||Â||1.9 to 8.6%|
|Flame Temperature||Â 3,596Â°F||Â||Â 3,615Â°F|
|Cubic Feet of Vapor, at 60Â°F, per pound||Â 8.5||Â||6.5|
This is pretty neat info! Now we can tell how much fuel each appliance consumes.