expired CO2 tanks.... question

[Panderson1]

I didn't realize they can expire one was expired since 2015. I've been bringing them to a liquor store owned by some middle eastern dude. He obviously didn't care lol.

Anyways what is wrong if they are expired? I brought them to a legit oxygen store today and they would only swap them. Ended up costing me $50 more but I figured maybe it's safer. Could they explode?

 

[VikeMan]

Could they explode?

It's rare, but it can happen. That's why CO2 cylinders are retested every 5 years.

 

[BigEd]

Just about any pressurized gas cylinder has an expiration date. If you use bottled propane those are dated as well. The home propane cylinders used for grills and cookers are disposed of when the expiration date is reached while the heavy, industrial cylinders for CO2, O2, welding gases, etc can be tested and re-certified for additional use. Explosion is unlikely but a tank containg oxygen or a flammable welding gas could cause a real issue if it starts to leak. The guy at the liquor store is breaking the law by filling expired cylinders not to mention causing potential damage for the customers or the wasting of a tankful of CO2. $50 seems a like a lot for a re-cert charge. You may want to look into industrial gas and welding supply dealers in your area for your CO2 fills.

 

[Qhrumphf]

They need to be recertified (basically pressure testing the cylinder above the normal pressure to verify its integrity). That's what the extra cost is for. I think CO2 tanks require recertification every 5 years.

If the tank isn't corroded I'd think the risk of it bursting is very small, but I'd never want to be anywhere near a rupturing gas cylinder. And given the devastation a high pressure cylinder could cause if it fails, I imagine there's a hefty safety margin built into the government regs. I'd still try to avoid being in possession of an expired tank. The general rule is if you receive a tank too close to its date, ask for a different one.

 

[IslandLizard]

There's a testing date stamped in the neck area. They need to be recertified (hydrotested) every 5 years. This comes up when you're trying to refill one that has expired (5 years past last stamped date). This could be a day after the 5 years are up or 10 years past due.

Many industrial gas services just swap without even looking at the date. They get them tested when needed, often at their main filling facilities, on their own dime (well, maybe 10% of your refill/swap cost goes to testing). Part of the business. Others want you to pay for it, usually smaller outfits, etc.

So call around next time, check prices and recert fees if needed.

Hope you got a nice one in return!
Sometimes they try to give you a rusty, heavy steel tank for your new shiny aluminum one... that should not be acceptable to you. Demand aluminum for aluminum at the very least!

Them charging you $50 for the hydrotest is really pushing it. You can get that done for around $30 usually.

 

[camonick]

The home propane cylinders used for grills and cookers are disposed of when the expiration date is reached

This is not true. I work for a company that is a propane supplier among other things and I am CETP certified. Propane cylinders can be used indefinitely as long as they meet requalification requirements.

Edit: spelling

 

[BigEd]

This is not true. I work for a company that is a propane supplier among other things and I am CTEP certified. Propane cylinders can be used indefinitely as long as they meet requalification requirements.

Did not know that. Just about all the 20 lb propane tanks I've seen towards the end of their date look like they are ready to be melted down. What is the rough cost of re-cert?

 

[camonick]

Did not know that. Just about all the 20 lb propane tanks I've seen towards the end of their date look like they are ready to be melted down. What is the rough cost of re-cert?

Can’t speak for other companies, but we don’t charge anything since it’s a simple visual inspection. It’s just a service we offer when we refill tanks. There is a checklist of items to be looked at (no dents, good paint, proper valving, intact foot rings, rust free, etc.). Only takes a minute or two then the bottle can be refilled after adding a new inspection date. If the tank fails the inspection, we either repair it or replace it (both at a cost).

 

[matt_m]

There is a checklist of items to be looked at (no dents, good paint, proper valving, intact foot rings, rust free, etc.).

Based on the ones I see, I'm assuming it fails if it doesn't have dents, missing paint, rust or other damage?

 

[Qhrumphf]

Can’t speak for other companies, but we don’t charge anything since it’s a simple visual inspection. It’s just a service we offer when we refill tanks. There is a checklist of items to be looked at (no dents, good paint, proper valving, intact foot rings, rust free, etc.). Only takes a minute or two then the bottle can be refilled after adding a new inspection date. If the tank fails the inspection, we either repair it or replace it (both at a cost).

Are they not hydrostatically tested like most cylinders? Or are the requirements lower since the pressure in a propane tank is on the lower end compared to other gases?

 

[Vale71]

It's country dependent but hydrostatic testing is only mandatory above a certain rated pressure, otherwise a simple inspection is enough.

 

[camonick]

Are they not hydrostatically tested like most cylinders? Or are the requirements lower since the pressure in a propane tank is on the lower end compared to other gases?

No, not usually. They are hydro tested when new. They have to be requalified 12 years after the date of manufacture and every 5 years after that. I can’t say with 100% certainty, but I just about guarantee all your big companies that do exchanges (Blue Rhino, Amerigas, etc.) only do the “External Visual” requalification when they refill bottles. We’re talking about a vessel that has a vapor pressure just over 200 psi on hot days. As long as it’s not compromised, it can be assumed to be safe. The visual inspection is quite subjective depending on the technician doing it and you can see that by the condition of the tanks you see at some exchange facilities. See my link in post #6 for the US DOT requirements.
Hydro testing requires specialized equipment, takes time, requires specialized personnel and is expensive to do for those reasons.

 

[camonick]

I didn't realize they can expire one was expired since 2015. I've been bringing them to a liquor store owned by some middle eastern dude. He obviously didn't care lol.

Anyways what is wrong if they are expired? I brought them to a legit oxygen store today and they would only swap them. Ended up costing me $50 more but I figured maybe it's safer. Could they explode?

My apologies to the OP. This thread has severely veered off course.

What expires is the test date. That doesn’t necessarily mean the tank is automatically unsafe. It just needs to be re-tested to ensure it is still safe to hold the pressure it’s designed to. The risk of an explosion or rupture is VERY minimal. The type of test is dependent on the intended use of the vessel and the DOT requirements applied to said vessel. That being said, anyone who refills said vessel is required to verify it still has a valid test date (regardless of contents). Some companies don’t charge for the testing service (especially if it’s THEIR tank and they’re in the business of exchanging them), others do. As you’ve found out, some charge a fair amount. It is mostly because of the liability responsibility involved in this litigious society we live in.

 

[Qhrumphf]

It's country dependent but hydrostatic testing is only mandatory above a certain rated pressure, otherwise a simple inspection is enough.

That was my thought. Figuring a room temp propane tank is ~150 PSI where a room temp CO2 cylinder is what, 800-something PSI? Apparently (in the US at least) either side of whatever regulatory threshold it is.

 

[SmallScaleOperator]

In addition to industrial gas supply and welding supply stores, check fire suppression contractors and shops. Like the places that design restaurant kitchen hood vents, and marine fire extinguishers. Best price I ever got was $10 refill any tank up to 20 lb. $15 recert inspection.

Worst price I was ever quoted was $7 per lb!!!

 

[Bobby_M]

When I accumilate about 30 tanks that need retesting, I drop them all off at a place that does it. They normally charge individuals $27 per tank but since we do them in bulk we pay $20. That's exactly the surcharge I assess to the customer when they turn in an out of date tank.