Just because you needed to know….C3H8 is the molecular formula of propane. Here is another…..Did you know Wells Brothers replaces and fills propane cylinders, and we charge by the gallon? Propane cylinders have a born-on date stamped on the cylinder’s collar. They are valid for 12 years or the manufacturer’s recommendations. After that date, they are considered out of date, and by law, we can’t fill that cylinder.
The most common cylinders are called grill bottles or a 20-pound tank. These types of cylinders will hold 4.5 gallons of propane. Propane weighs 4.2 pounds per gallon. This gives us a total propane capacity of 18.9 pounds per cylinder. This information is important since the State of Texas allows a maximum of 90 pounds of propane to be transported in a closed-body vehicle. This means the maximum number of cylinders you can haul in your car, van, suburban, etc. is 4 (18.9 x 4 = 75.6 pounds of propane). Here is some more fine print, once a propane cylinder has been filled, it is considered always full. So folks show up to refill 5, empty, 20-pound cylinders in the trunk of a car. We can’t fill any of them. Why? 4 cylinders are, by law, the maximum number of cylinders that can be transported in a closed-body vehicle and they have 5 to start with.
“Closed-bodied vehicles such as passenger cars, vans, and station wagons must not be used for transporting more than 215 lb. water capacity [90 lb. propane capacity] but not more than 108 lb. water capacity [45 lb. propane capacity] per cylinder unless the driver and engine compartments are separated from the cargo space by a vapor-tight partition that contains no means of access to the cargo space.” NFPA 58,§9.3.2.5(B)
I hope this information will help you in the future and that you consider Wells Brothers the next time you need propane.