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Member Section => Down Range Cafe => Topic started by: fightingquaker13 on May 17, 2011, 04:22:14 PM

Title: How long does propane last?
Post by: fightingquaker13 on May 17, 2011, 04:22:14 PM
I have a supply of bulk propane cylinders (think gas grill size). Some of them are pushing 4 years old. Are they still ok, or do I need to empty and refill them?
FQ13
Title: Re: How long does propane last?
Post by: Majer on May 17, 2011, 04:36:33 PM
if they were stored properly they should be fine to use. I would check the date on the containers to make sure they are within their useful life and use up any that are getting close. You can still use them if they are past the date you just cant get them refilled. Hope this helps.
Title: Re: How long does propane last?
Post by: TAB on May 17, 2011, 04:46:10 PM
the cylinder life cycle is shorter.
Title: Re: How long does propane last?
Post by: Pathfinder on May 17, 2011, 05:06:00 PM
Propane never goes bad. Seals on the cans are a whole 'nuther story though. After only 4 years, the seals should still be OK, but YMMV.
Title: Re: How long does propane last?
Post by: ellis4538 on May 17, 2011, 05:42:46 PM
Tanks are supposed to be OK for 10 years before needing to be tested but the place I get mine filled said that they check for rough handling and decide...just to be safe!

FWIW

Richard
Title: Re: How long does propane last?
Post by: kmitch200 on May 17, 2011, 08:05:13 PM
I have a supply of bulk propane cylinders (think gas grill size). Some of them are pushing 4 years old. Are they still ok, or do I need to empty and refill them?
FQ13

What they said. The cylinder goes bad before the gas does.

Doing a quick search found this:
The most common portable tank is called a "DOT" tank, since it is built to conform to design and usage regulations established by the Federal Department of Transportation. 
DOT tanks may only be used for 12 years after the manufacturing date. (This is according to a standard created by the National Fire Protection Association, and adopted as law by most states).


A 4 year old tank is fine. (excluding damage of course)
Title: Re: How long does propane last?
Post by: dipisc on May 17, 2011, 08:41:29 PM
Hi;

     Glad someone asked/posted this question. As a non-active scuba diver, whenever I had to get my tanks hydrostated there was no mention of shelf life on the tank. I thought that propane tanks were the same - good until they could not pass the test sort of thing.
Title: Re: How long does propane last?
Post by: billt on May 17, 2011, 08:45:17 PM
How many PSI are they under when they are full?    Bill T.
Title: Re: How long does propane last?
Post by: TAB on May 18, 2011, 02:09:59 AM
That depends on temp and if there is liquid in the tank or if its all gas.

at 162 degrees the presure will be 390 psi.  most tanks have a presure release valve at about 375.

at 70 it should be 124 psi.


Then there is storage for transpertation and as fuel for cars/trucks.  thats a whole diffrent animal.
Title: Re: How long does propane last?
Post by: billt on May 18, 2011, 05:45:35 AM
So say a 20 pound barbecue grill tank full, when it's 115 outside on the patio is close to what, pressure wise? I ask because I got this thing parked right up against the house. There is no where else to put it.  Bill T.
Title: Re: How long does propane last?
Post by: crusader rabbit on May 18, 2011, 07:52:09 AM
Bill, my pappy has had propane torch tanks stored in the garage at his place in Mesa, not that far from you--some for over 20 years--and they are still just fine.  I suspect the seal will start leaking the first time they are used, but they are still holding pressure.  Personally, I would probably like to see them stored outside the garage, but still under some shade from direct sunlight.

And Quaker, propane--C3 H8 or butane C4 H10 (similar gasses) are hydrocarbon gasses and will last indefinitely until they are chemically changed by combustion.  You can also alter their form by compression.  Compress them enough and they become liquid (that's what you hear/feel sloshing around in the cylinder.  Their composition can be altered by introducing other elements--something you are unlikely to try outside of a lab.

The concern, as has been mentioned above, is the integrity of the tank.  If you see obvious deep rust (Iron oxide has something like 80-times the volume of solid iron, so even something that looks bad may be from a very thin layer of original material), take the tank away from any structures and/or ignition sources open the valve.  If these tanks are as old as I suspect, they will not have the intigrated safety feature that prevents the discharge, and they will empty out into the atmosphere.  If they are newer, you will have to hook up a hose fitting or the gas won't release.

If these tanks were mine, I would hook 'em up to my bbq, buy quantities of pork ribs, beef ribs, and hamburger meat, invite over my plethora of friends who like free food, and stipulate that they must bring beer.  I would move the bbq away from the house for this activity, but there really should be no great worry.  Of course, if you hear a hiss, make a hasty retreat.  You are unkilely to get an explosion--buut you could see a pretty neat flare for awhile.

You could also try shooting them with a tracer (keep a very safe distance) and enjoy the ensuing explosion.  If you get sent to prison anywhere in my neck-o-the-woods for terroristic activity, I'll come see you and bring some homemade cookies. ;)
Title: Re: How long does propane last?
Post by: Timothy on May 18, 2011, 09:25:06 AM
I'll add to CR's post that, if you do vent these tanks to atmosphere, make sure the neighbors aren't watching.  It's illegal in my area, don't know about Florida. 

Smoking during this procedure would be ill advised as well... :P
Title: Re: How long does propane last?
Post by: tombogan03884 on May 18, 2011, 11:33:00 AM
From CR's post :
"I would hook 'em up to my bbq, buy quantities of pork ribs, beef ribs, and hamburger meat, invite over my plethora of friends who like free food, and stipulate that they must bring beer. "


This FQ we're talking about, the guy who has to tie a Hibiscus flower around his neck to get the Iguana's to play with him.
Title: Re: How long does propane last?
Post by: fightingquaker13 on May 18, 2011, 11:41:01 AM
That's just to lure them in close for the kill Tom. And an excellent source for using up gas for the free BBQ. "Oh, that, its chicken? Done up Guetmalan style, its got an interesting marinade don't you think"? ;D
FQ13
Title: Re: How long does propane last?
Post by: Solus on May 18, 2011, 11:46:52 AM
If you vent them, do it on a breezy day.  

Propane is heavier than air and will accumulate in low areas (this is the reason LP is NOT a good idea to be use on boats)

CR has the best idea.  

If you don't use your tanks enough to have they refilled before the tank expiration date, have that BBQ.  

If you do use them quick enough, have them refilled until the last refill before expiration, then do the empty exchange.

They don't check the expiration date on the tank you bring in and they will give you an unexpired full one.

Haven't done any costing on these two options so I don't know how they compare.  The exchange path does take less time as there is no waiting for the refill and exchange location might be any gas station.

Title: Re: How long does propane last?
Post by: tombogan03884 on May 18, 2011, 11:47:16 AM
It's dead.
It's cooked.
It's free.
Shut up and eat.
Here's more potato salad.   ;D
Title: Re: How long does propane last?
Post by: Timothy on May 18, 2011, 11:50:15 AM
It's dead.
It's cooked.
It's free.
Shut up and eat.
Here's more potato salad.   ;D

And a chaser of antibiotics for the salmonella....   
Title: Re: How long does propane last?
Post by: Badgersmilk on May 18, 2011, 05:37:20 PM
http://floridakeystreasures.com/category/recipes/iguana/ (http://floridakeystreasures.com/category/recipes/iguana/)

I'd try it once anyway.  Can't be any worse than eating oysters!  Exactly what was the first guy to eat an oyster thinking when he put THAT in his mouth?  ???