Propane Weights and Measures

[Gypsy George]

1. Liquid Propane weighs approx 4.26 lbs per gallon at 60 degs
2. A full 30lb Propane tank would weigh approx 75 lbs ?
3. A Propane tank should be filled to only 80% of capacity
to allow for expansion according to Federal Regulations
4. An empty 30lb propane should be filled with no more then
5.6 gallons to allow room for expansion or 80% full
according to the formula above.
5. An empty 30lb propane tank would weigh approx 51lbs. ?
6. I have had Propane dealers fill my 30lb tanks with as much as
7gallons of propane using a propane filling meter, they would
open up the bleeder valve and fill it untill liquid came out of
the valve, so 7gallons of liquid propane X 4.26 lbs per gallon
liquid equals 29.82lbs in a 30lb tank leaving no room for
expansion of the gas in warmer weather
7. My question is, was I in any danger with those tanks being filled
with 7 gallons or am I now just being paranoid

[TomW]

Welcome to the forum.



I did not follow all that but, if your propane dealer stopped filling when fog came out of the bleeder screw then you are okay.

Tom

[eubank]

Ok, lemme see if I can sort this out a little bit:

Originally Posted by Gypsy George

1. Liquid Propane weighs approx 4.26 lbs per gallon at 60 degs

Yep.

2. A full 30lb Propane tank would weigh approx 75 lbs ?

It'll weigh approx. 30 lbs + the weight of the bottle itself, which is marked as "TW" on the collar of the bottle. (If you want to know the exact weight of the propane, take the "WC" marking from the collar -- that means "water capacity" -- and multiply it by .42.)

3. A Propane tank should be filled to only 80% of capacity
to allow for expansion according to Federal Regulations

Correctomundo.

4. An empty 30lb propane should be filled with no more then
5.6 gallons to allow room for expansion or 80% full
according to the formula above.

Nope. The full weight -- TW + (WC X .42) -- is calculated with the 80%
amount already factored in.

5. An empty 30lb propane tank would weigh approx 51lbs. ?

Depends on the bottle. Check the "TW" figure on the collar.

6. I have had Propane dealers fill my 30lb tanks with as much as
7gallons of propane using a propane filling meter, they would
open up the bleeder valve and fill it untill liquid came out of
the valve, so 7gallons of liquid propane X 4.26 lbs per gallon
liquid equals 29.82lbs in a 30lb tank leaving no room for
expansion of the gas in warmer weather

It is not unusual to put 7 gallons into a 30 lb tank. Well, sort of unusual, given that many folks bring in their bottles for filling before they're completely empty.

7. My question is, was I in any danger with those tanks being filled
with 7 gallons or am I now just being paranoid

Nope, no danger.


Lynn

[Druupy]

Just did the porpane refill today.

I figure on 7 gallons in the 30# tank.

The way I find out what the fluid level is?

Weigh the tank.

Empty 30# tank = 20#

Full 30# tank = 50#

AND, all the new tanks have overflow protection valves. Meaning you can't over fill the tank because an internal valve closes and won't take anymore propane. The most I've gotten into an "empty" tank is 6.7 gallons, and that is what the filling station charged me for. At least it felt empty to me.

[snake]

Originally Posted by Druupy

AND, all the new tanks have overflow protection valves. Meaning you can't over fill the tank because an internal valve closes and won't take anymore propane. The most I've gotten into an "empty" tank is 6.7 gallons, and that is what the filling station charged me for. At least it felt empty to me.

I don't have 100% confidence in the overflow protection devices, 98% maybe, but not 100%.

I like to see proper safety procedures when my tanks are filled.

[LI Pets]

Originally Posted by Druupy

Just did the porpane refill today.

I figure on 7 gallons in the 30# tank.

The way I find out what the fluid level is?

Weigh the tank.

Empty 30# tank = 20#

Full 30# tank = 50#

My 30G tanks have to be replaced, the local guy wants about $62 for the 30G and $68 for the 40G.

So I plan on getting the40's.

I already moved my battery inside back 3 feet, and removed the univolt, so the tongue weight will still be a bit lower.

If a 30 = 50lbs does a 40 weight 1/3 more or about 65lbs?

[azflycaster]

This chart was copies from the vintage trailer supply website


These numbers are for aluminum tanks. I would think the capacity would be the same for steel tanks.

[LI Pets]

Thanks, so it's about 10lbs more in propane and few more lbs in steel.

So 15 may 20 at most additional lbs.

[azflycaster]

Why not ask Santa for a pair of aluminum tanks? They are pricey and you need to polish them, but they do look nice!

[LI Pets]

Santa just brought me a GMC, his bag is empty

[azflycaster]

Wow, I like your Santa!

[LI Pets]

oops, I saw a few nice dog toys in there, I'll e-mail him and ask if going to be in Arizona soon

[eubank]

Originally Posted by snake

I don't have 100% confidence in the overflow protection devices, 98% maybe, but not 100%. I like to see proper safety procedures when my tanks are filled.

Yes, that's why we're not supposed to rely on the OPD when filling a bottle here in NM. (I've been told that some fillers here do so anyway; I guess they're just too lazy or stupid to do a little mental calculating before using the scale that they all have by law anyway.)

Lynn

[peegreen]

I wasn't trained on the filling procedure, but..... the guy at the rental place where I get my bottles filled waits for the OPD to stop the propane flow. That's how he knows the bottle is full, the shuts off the pump at the filling station. I'm not quite sure I completely understand the concept of the bleed valve when using a bottle with an OPD valve. It's not registering. I don't recall a bleed valve on the new OPD's, but haven't closely examined. If this is the method being used, the OPD would shut off when full. You're not paying for a full tank when liquid starts to vent but propane is still being supplied.

[eubank]

Welll, it boils down to the propane recommendations in the National Fire Safety Assn propane manual, which individual states are free to adopt or to modify. For example, NFSA says to fill DOT bottles as on RVs either by weight (a scale) or by volume (using the bleed valve), but NM wants fillers to use weight unless volume is necessary. (It's an environmental thing: Filling by volume always shoots a certain amount of propane into the air.) Noteworthy is that the NFSA does not mention or suggest using the OPD valve as a means of filling.

But, again, the NFSA manual is a set of recommendations. It's possible that some state someplace could permit filling with the OPD valve. (And it's also true that a number of fillers in states that disallow using the OPD do so anyway.) Personally, I wouldn't: It's like trusting a mechanical device that sometimes fails with somebody else's well-being. Ultimately, if a filler illegally uses the OPD to fill, overfills a bottle, and an accident results, the filler could (and should) be held responsible.


Lynn

[Tarheel]

My 40# tanks usually take 9 gallons when empty. I'm glad to see that they weigh almost 100 lbs, I don't like carrying them, blamed it mostly on my age.

[Gypsy George]

Thanks everybody for your input, now feel safer knowing things
are ok. The weights I listed on the full and empty tanks were
done without actually weighing the tanks. Gypsy George

[wingfoot321]

You guys are good ! No where else on the internet could a person get better information with such good detail and discussion. That is why I read here quite a lot.

[TomW]

Originally Posted by wingfoot321

... No where else on the internet could a person get better information with such good detail and discussion...

Well Duh!

Airstreamforums.com is comprised of the best of the best!

Tom

[walter1]

Duh, what size are my tanks???

My Manchester steel tanks are marked W.C. 71.4#

multiplying that by .42= 29.988

TW=25.6 (tare weight)

My old original steel tanks are marked PST WC 66.7
multiplying that by .42=28.014

Does that mean these are considered 30 pound tanks?