# Propane tank longevity **URL:** \ **Category:** Factual Questions\ **Created:** [February 4, 2009, 5:53pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444 "2009-02-04T17:53:06Z")\ **Posts on this page:** 7\ **Page:** 3
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [February 6, 2009, 4:15pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/41 "2009-02-06T16:15:45Z")
> [@WarmNPrickly](#): > > They said “It’s empty”. OK, on what basis did your supplier think that your tank was empty? You said the gauge read 60%, after all. (BTW, your gauge sounds like it’s off; it should have read about 40% if it took 300 gallons to fill your tank.) I’m guessing they didn’t look inside… :dubious: FWIW, my supplier typically fills the tank when it gets down to about 40% by the gauge. And I usually get about 300 gallons when the tank is filled at that point. And of course, 300 gallons is exactly 60% of a 500-gallon tank. Maybe your supplier considers 200 gallons remaining to be “empty” if they typically fill a 500-gallon tank at that point. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [February 6, 2009, 4:22pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/42 "2009-02-06T16:22:07Z")
> [@WarmNPrickly](#): > > Neither. I know what 500 gallons looks like. I just went out at measured it. \*\*It has a circumference of 10 ft and a length of 8 ft. \*\* That gives me a total volume of 340 gallons assuming no thickness of the walls. It’s larger than my eyeball measurement had it at. You can check my math if you like. The supplier has me listed as a **500 gallon tank** , and it looks to be the exact same size of every 500 gallon propane tank I’ve seen. When we bought 300 gallons of propane this fall our tank was empty. The meter read 60%. Your dimensions are **close** to the tank [listed on this site](http://www.airgas.com/content/details.aspx?id=7000000000215) that calls the tank a 500 lbs cylinder not a 500 gal. cylinder. Now I am not sure if the 20% vapor space has been deducted from this sizing or not. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [February 6, 2009, 4:32pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/43 "2009-02-06T16:32:58Z")
> [@Gbro](#): > > Your dimensions are **close** to the tank [listed on this site](http://www.airgas.com/content/details.aspx?id=7000000000215) that calls the tank a 500 lbs cylinder not a 500 gal. cylinder. There’s a typo on that table. Look across the table, and you can see that that same table lists the approximate capacity of that tank as 1,692 lbs/400 gallons. It should be listed as a 500-gallon cylinder. This is the nominal volume, of course. ---
**Author:** ![Gbro](https://avatars.discourse-cdn.com/v4/letter/g/c6cbf5/32.png) [@Gbro](https://boards.straightdope.com/u/Gbro)\ **Post date:** [February 6, 2009, 4:46pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/44 "2009-02-06T16:46:56Z")
> [@WarmNPrickly](#): > > They said “It’s empty”. The propane delivery man [only uses the fixed level gauge](http://www.propane101.com/fixedliquidlevelgauge.htm) when filling your cylinder. We call this bleeder the 80% valve. You read the [tank level gauge or face gauge](http://www.propane101.com/floatgauge.htm) that may not work properly, or was the incorrect one to start with. Then he will read the gallons delivered from his meter a that is the only way to tell how much liquid was delivered. And you did pay for the gas that was discharged into the atmosphere while [he was filling your tank](http://www.propane101.com/propanedeliveryquestions.htm)😃 ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [February 6, 2009, 10:05pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/45 "2009-02-06T22:05:24Z")
> [@robby](#): > > OK, on what basis did your supplier think that your tank was empty? You said the gauge read 60%, after all. (BTW, your gauge sounds like it’s off; it should have read about 40% if it took 300 gallons to fill your tank.) > > I’m guessing they didn’t look inside… :dubious: > > FWIW, my supplier typically fills the tank when it gets down to about 40% by the gauge. And I usually get about 300 gallons when the tank is filled at that point. And of course, 300 gallons is exactly 60% of a 500-gallon tank. > > Maybe your supplier considers 200 gallons remaining to be “empty” if they typically fill a 500-gallon tank at that point. I didn’t say they filled it, I said we got 300 gallons. The guage read 0 before they filled it, the guage read 60 after they put 300 gallons in it. The guage read exactly what it should have read for getting 300 gallons. ---
**Author:** ![WarmNPrickly](https://avatars.discourse-cdn.com/v4/letter/w/d78d45/32.png) [@WarmNPrickly](https://boards.straightdope.com/u/WarmNPrickly)\ **Post date:** [February 6, 2009, 10:15pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/46 "2009-02-06T22:15:04Z")
Damn! missed the edit window. My error was in my eyballing the volume to be less than 500 gallons. Also, I can’t use a calculator anymore. It turns out that my tank is in fact 500 gallons, and all is well with the world. Until today, I was always wondering what they meant by gallons since I didn’t think my tank could possibly hold 500 gallons. Turns out, what they meant was actually gallons. ---
**Author:** ![robby](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robby/32/11048_2.png) [@robby](https://boards.straightdope.com/u/robby)\ **Post date:** [February 7, 2009, 7:31pm UTC](https://boards.straightdope.com/t/propane-tank-longevity/484444/47 "2009-02-07T19:31:40Z")
> [@WarmNPrickly](#): > > I didn’t say they filled it, I said we got 300 gallons. The guage read 0 before they filled it, the guage read 60 after they put 300 gallons in it. The guage read exactly what it should have read for getting 300 gallons. > [@WarmNPrickly](#): > > Damn! missed the edit window. > > My error was in my eyballing the volume to be less than 500 gallons. Also, I can’t use a calculator anymore. It turns out that my tank is in fact 500 gallons, and all is well with the world. Until today, I was always wondering what they meant by gallons since I didn’t think my tank could possibly hold 500 gallons. Turns out, what they meant was actually gallons. Well, okay, then. 😃 [Previous page](https://boards.straightdope.com/t/propane-tank-longevity/484444.md?page=2)