More Propane Issues

[mary and bob]

Here's some more safety information related to propane tanks. Many of you know that propane tanks [or cylinders] have to be inspected and recertified after a certain period of time. I have a couple of the 11lb tanks that we use for camping grills, and one needed to be refilled. Many years ago I worked for a fuel oil & propane company, so I decided to visually inspect my tank before taking it to be filled. I've found some filling stations don't even look at the date stamped on the tank. The tank in question has a 2001 date so it is due for recertification this year as 12 years is the specified time period for the first inspection from new. As I was looking over my tank I found some scaly rust on the bottom, scraped it off, and found serious pitting under it. This tank would fail an inspection done by a qualified person so I'll have to scrap it. I consider it unsafe to fill. Moral of the story; don't just depend on the filling station to find any problems, do your own visual inspection.

[Donna D.]

Originally Posted by mary and bob

...Moral of the story; don't just depend on the filling station to find any problems, do your own visual inspection.

EXCELLENT advice

[mary and bob]

Thanks Donna, and the thing is I'm embarrassed that this tank got this bad and I didn't see the problem sooner because I know better. I'd bet that I could take it to my local farm store where I get my tanks refilled and they would fill it. I've marked that tank as no good and I'll dispose of it at my local transfer station [dump]. This is where the tank exchange places like Blue Rhino or Amerigas is good because those tanks get inspected before every refill. If you're looking to make an exchange and then keep that new tank you want to get one with a recent date stamp. Unfortunately no one does exchanges on the 11lb tanks so I'll have to buy a new one.

[Thomas G.]

Good catch. I didn't realize that propane had such a steep vapor pressure curve. I can see where a dark tank in the sun could get well over 100 degrees F.

[Brian B-P]

Originally Posted by mary and bob

I've found some filling stations don't even look at the date stamped on the tank.

The only person at a filling station that I have ever seen checking the date on a propane cylinder was at Costco, where they seem quite diligent. The rest of them - at various gas stations and RV parks - will happily pump propane into any tank, without a glance at any of the markings or consideration for the condition. They also fill by weight (which is good) but to a standard weight for the tank size, regardless of the actual tare weight of the tank; I shudder to think what they do with aluminum tanks.

If you're depending on the "professional" at the filling station to take care of your safety, you are completely unprotected.

[Thomas G.]

Originally Posted by Brian B-P

.........
If you're depending on the "professional" at the filling station to take care of your safety, you are completely unprotected.

I used to have a horizontal tank bolted to the underside of my travel van. Once when in Mexico, they filled it until propane was squirting out out the vent.

I was sure the van was a goner. I just stood well back until it quit venting.

[Brian B-P]

Originally Posted by Thomas G.

I used to have a horizontal tank bolted to the underside of my travel van. Once when in Mexico, they filled it until propane was squirting out out the vent.

A relief vent, or an 80% fill bleed valve? The purpose of the 80% fill valve is to indicate that the tank if full, when liquid appears at the valve. The bleed valve is then closed and the filling stopped, leaving a properly filled (to 80% of total volume) tank.

I had one pair of incompetents - one a trainee, the other allegedly qualified but distracted by the female trainee and his teenage hormones - fill my motorhome's tank then put the fill cap back on and leave... leaving the bleed valve wide open.

[Thomas G.]

Originally Posted by Brian B-P

A relief vent, or an 80% fill bleed valve?.......

It has been 25 years, so the details are dim. Now that you have jogged my memory, I think what happened was that after I left, the relief valve blew. I opened up the 80% valve and let it vent until liquid quit coming out. I was praying that no smoker would toss out a lit cigarette.

[Brian B-P]

Originally Posted by Thomas G.

It has been 25 years, so the details are dim. Now that you have jogged my memory, I think what happened was that after I left, the relief valve blew. I opened up the 80% valve and let it vent until liquid quit coming out. I was praying that no smoker would toss out a lit cigarette.

That makes sense; here's a possible sequence of events:

1. tank if filled without opening the 80% bleed valve
2. tank was overfilled, leaving little or no vapour space
3. temperate rises, due to weather changes or van operation
4. pressure rises due to the temperature rise
5. safety relief valve opens to limit pressure, releasing any vapour and then liquid
6. Tom opens the 80% fill valve, releasing liquid until the liquid level reaches the correct level

Scary, and a reason to care whether or not the person filling the tank is doing it correctly. It is now common (and apparently required under U.S. federal regulations) to have a stop-fill device on fixed ASME tanks (which still requires monitoring with the 80% bleed valve), and an overfill prevention device or OPD (which is not for normal use stopping the fill process) on small portable DOT tanks.

[Thomas G.]

Originally Posted by Brian B-P

That makes sense; here's a possible sequence of events:......

Sounds right.

[KevinPete]

I worked part-time last summer at a place that filled tanks, got to see some real scary stuff. A couple times during the summer, there was a coupon for a cheap 20 lb. cylinder fill, one per customer. So of course, everyone grabbed any tank they had laying around, got a few coupons, and piled the tanks and the family in the car. One lady had 11 cylinders thrown haphazardly on top of a pile of trash/junk in the back of her minivan, which also held about 6 little kids. I explained to her that a few tablespoons of liquid would fill the entire van with an explosive mixture in seconds (after I told her to put her cigarette out). Rusty tanks, dented, broken valves, and one made in 1968!

We filled by actual tare weight and almost always, the OPD float shut the gas off before it was full by weight. Had a couple OPD valves fail and allow the tank to be completely filled, and since it was in the 90's, they started venting almost immediately.

I've been in fires where a 100-lb cylinder tipped over while burning, nothing like looking up the hill and seeing a wave of burning propane coming towards you!

The first few times I filled forklift tanks and 100-lb. tanks I was pretty nervous about having the vent open, but that's the way it's done.

And at least half of the "convenience store" exchange tanks were out of date and/or rustier than I would fill. Blue Rhino and several local brands, and with their brand label on them, not other tanks that customers had brought in to exchange. Some people complained to the boss that I was refusing to fill a tank, he told them that I was probably saving them from either burning their house down or dying, so they better listen.

Glad it was only for a few months, not a job I'd want to do all the time.

[mary and bob]

Kevin; thanks for sharing your experiences, it may make everyone more aware of propane safety. When I worked for Ryder before retiring 2 years ago, we had some tractors & trailers rented to a Blue Rhino dealer. They seemed to be good with the tanks that they distributed. The tanks always appeared to be clean with fresh paint. It's been about 25 years since I worked for a fuel company and regularly filled 20lb and fork lift tanks. I too never cared for that part of the job, preferred the fuel oil stuff more. I did some propane training at a Homgas place where they told all kinds of scary stories about propane accidents.

[Brian B-P]

Kevin, thanks for taking more care in the propane filling job than most.

Originally Posted by KevinPete

We filled by actual tare weight and almost always, the OPD float shut the gas off before it was full by weight. Had a couple OPD valves fail and allow the tank to be completely filled, and since it was in the 90's, they started venting almost immediately.

Something doesn't make sense here. If these tanks were properly filled by weight, they would not get overfilled, and so even if the OPD was completely non-functional they would not open the relief valve (vent). How did the ones in which OPDs apparently failed get "completely filled" if you were shutting off the fill at the correct weight?

[Kenny Strong]

there are questions about traveling with the tank be used; what are your opinions in this area?

[Imo.]

Thanks for the information on propane tanks. I often wondered why my house propane tank was only filled to 80%.....figured it was for expansion of the propane and not so the propane company could charge me those additional fees for delivery a couple of times a year.

[KevinPete]

Originally Posted by Brian B-P

Kevin, thanks for taking more care in the propane filling job than most.


Something doesn't make sense here. If these tanks were properly filled by weight, they would not get overfilled, and so even if the OPD was completely non-functional they would not open the relief valve (vent). How did the ones in which OPDs apparently failed get "completely filled" if you were shutting off the fill at the correct weight?

Not sure, I was running another filling station, and they started talking about the cylinder "leaking". I walked over, and after moving it to the wooded area nearby for safety, I realized that it was noticeably heavier. Cracking the valve open let liquid shoot out of the tank. It stopped venting after a couple hours in the shade, then was moved to the shop to be emptied and taken out of service.

Perhaps the other worker had the scale set too high, we had weights for other cylinder sizes, perhaps had the wrong one on there. It should have never happened, but these things do.

People are kind of paranoid about gas. My mother would never allow any gas appliances in the house, claiming they'd "blow up". People used to call 911 all the time when distributors got shipments in during the day. People would get a whiff of odorant and freak out. Interestingly, most of the "old timers" I know that fill small cylinders all day can't smell the odorant anymore.

[Brian B-P]

Originally Posted by KevinPete

... Perhaps the other worker had the scale set too high, we had weights for other cylinder sizes, perhaps had the wrong one on there.

That's a generous interpretation; it seems likely to me that while the wrong weight may have been set in some cases, in others the other worker was not nearly as diligent as Kevin, and just rammed those cylinders full without even checking the weight, counting on the OPD to stop the fill. Members of this forum have reported that their cylinders are filled this way, and even that they believe it is the correct method . Two problems with this:

• an OPD in a portable DOT cylinder is a secondary safety device, not the primary method to stop the fill (in contrast to fixed ASME cylinders, which do now come with stop fill devices)
• there are likely lots of 20-lb cylinders still out there without OPDs; as far as I know, an OPD is still not required in Canada (in any size), and new non-OPD cylinders were available quite recently

[Brian B-P]

Originally Posted by Kenny Strong

there are questions about traveling with the tank be used; what are your opinions in this area?

This (going down the road with the propane tank open to supply propane to run the refrigerator) has been rehashed many times in this forum. Perhaps we could keep this topic to the condition of propane tanks and how they are filled?

[mary and bob]

Originally Posted by Brian B-P

. Perhaps we could keep this topic to the condition of propane tanks and how they are filled?

Thanks Brian; I decided to start this thread after I discovered a serious rust issue on one of my 11lb tanks. I wanted to point out an issue that others may not be aware of, because how many of us actually examine our tanks, especially the bottom, before taking it for a refill. And we can see by some comments that some of the people filling tanks aren't paying attention to any problems either. And as Kevin has experienced, most people are only interested in getting their tank filled, and more so if it is a bargain price, never mind the condition. Another question is how do we transport our tanks to and from the filling station or exchange location? I've found that a 20lb or smaller tank fits nice and tight in a milk crate, keeps it from tipping over. I'm happy to see there is some interest in this thread, be safe!!

[Brian B-P]

Originally Posted by mary and bob

I wanted to point out an issue that others may not be aware of, because how many of us actually examine our tanks, especially the bottom, before taking it for a refill.

A couple of winters ago I realized that some small cylinders that I was using around my property were accumulating mud frozen into the bottom, within the foot ring. This is bad because it means I get less propane when the tank if filled by weight, but more importantly because the condition of the bottom can't be inspected... although this didn't bother anyone filling them.

Removing the frozen stuff by chipping it out risks scraping the paint and starting rust, so I made a point of cleaning the bottoms with a pressure washer (at a car wash in winter) and keeping them clean by placing the tanks on pads (such as concrete blocks) rather than directly on dirt or gravel.

We had our motorhome in an RV park over a winter season, and used propane from an external 240 pound tank. The tank was rented from a propane supplier, and when they delivered it they placed it on a concrete sidewalk block. This both keeps the bottom clean and stabilizes the tank. I'm not suggesting that anyone travel with concrete blocks, and it isn't an issue for us when traveling with the Boler (because the tanks stay on the trailer), but people who use separate tanks (such as to run a barbecue or outdoor stove) might use something like a jack pad for this purpose.