20 lb LP (Liquid Propane) Tanks

abracadabra · 08-26-2008, 12:34 PM

Once again this widely misunderstood topic has come up. So I thought I'd try to shed some light on the subject.

20 pound Propane tanks

While these tanks technically have the capacity to hold 20 lbs most all propane tanks are only filled to 80% capacity with LP (liquid propane)that equals 16 lbs for a 20 lb tank the other 20% is gas. In many states it's the law because of safety concerns.

EDIT: Also it is apparently a DOT requirement for portable tanks.

Here's a piece that explains it a little better:
http://arfarfarf.com/fire/articles/propane_weight.php

They do the same thing with large stationary tanks that are built with steel 1/4 in. thick. The propane company will only put 400 gal in my 500 gal tank.

LP weights 4.2 lbs per gal at 60*F so you get slightly less than 4 gal per 20 lb tank.

jspence1 · 08-26-2008, 01:06 PM

In canada all of our newer tanks have a float in the tank that prevents filling above the the 80% mark. Not like in the old days when we'd fill the tanks till they wouldn't hold any more...well at least our own tanks

John

**GilaMinumBeer** · 08-26-2008, 01:10 PM

Typically, my tanks weigh in at 34lbs, full.

And an empty tank weighs 17lbs.

YRMV.

I use these figures coupled with a bathroom scale to monitor the amount of gas in the tank. I have yet to determine how much weight I burn in an hour tho'.

That is something I plan to track on the next brewday.

**Homercidal** · 08-26-2008, 02:31 PM

All the new OPD tanks have valves to prevent overfilling (Overfill Protection Device). FYI - If you open the valve too far, it will not flow properly. Then you must remove the fitting from the valve to release the pressure and reconnect and try again. Had a problem with my camper found out it was because I opened the new valves too far.

wihophead · 08-26-2008, 03:46 PM

Quote:

Originally Posted by Homercidal

All the new OPD tanks have valves to prevent overfilling (Overfill Protection Device). FYI - If you open the valve too far, it will not flow properly. Then you must remove the fitting from the valve to release the pressure and reconnect and try again. Had a problem with my camper found out it was because I opened the new valves too far.

It will do that if you open them too fast...

wildwest450 · 08-26-2008, 03:53 PM

My 16.5 lb tank weighs 38lbs when im done filling it. Of course that's the benefits of having your own filling station. That's as full as you want to fill one, even using the spitter valve when filling, you can get a nice explosive pop off if you fill them that full when it's over 75f out.