Im looking to replace a couple of old small air compressors i have tied together. Right now the combined capacity between the two tanks is 20 gallons. One is a very quiet single cylinder that probably only puts out a few cfm at 90 but i love how quiet it is. Problem is the tank is ancient and concerns me. Second compressor is a loud direct drive unit that produces 4cfm at 90 but i can’t hear anything else when it’s running. I am interested in these new oil free ultra quiet compressors but they don’t seem to have asme tanks. Even the larger 30 gallon belt drive compressors 110v compressors don’t seem to have many with asme tanks. How important is an asme rated tank and are consumer non asme tanks fine?
How important is an asme rated air compressor tank?
- Thread starter Joe green
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Bill T
Well-known member
If you are the average homeowner buying a new compressor, no big advantage. If you are a business, your state may require an ASME tank. Insurance companies for industry also specify ASME tanks. If you are buying a used compressor, ASME tanks show the date. That is good information if you are deciding to buy a used compressor.
stonesfan68
Well-known member
I’d be shocked if there were any air compressors for sale in this litigious country that didn’t have an ASME tank. If the tank is considered a pressure vessel- and most tanks rated for higher than 15 PSIG would be- then it will have an ASME stamp. I’ve been in the compressor industry for 30-years and wouldn’t consider buying a tank without the stamp.
rlitman
Well-known member
Good luck finding an ASME rated compressor tank that's smaller than 60 gallons. They're NOT the norm. The tank will likely have stampings from the manufacturer with a date and pressure rating, but that isn't an actual ASME marking.
Prepared to be shocked!
A lot of the 60 gallon home owner quality units are not ASME rated. The smaller 5'ish gallon sizes, most are not rated either. Certainly there are a few manufacturers that have rated tanks, but on the smaller units not rated is typical.
tinmanwpk
Well-known member
ASME is worth it to me.
ASME is pretty nearly not available on consumer-grade compressors because it's a considerable extra expense. There are always guys who will tell you horror stories about tank explosions, but for a home garage compressor, as long as you drain the condensate regularly, it's really not at all likely that it will explode and vaporize your house. If consumer-grade tanks were really dangerous and prone to failure in home use, the manufacturers would long ago have been sued out of existence.
All of that goes out the window if you are using it all day every day. In that case, get a higher-grade unit.
There are folks that will tell you that nothing less than Snap-On will do for a screwdriver to keep in your kitchen drawer, and others who will swear that all you need is Harbor Freight tools to repair the Hubble Space Telescope in orbit. Just pick something that is rated for your actual usage and get on with the job.
All of that goes out the window if you are using it all day every day. In that case, get a higher-grade unit.
There are folks that will tell you that nothing less than Snap-On will do for a screwdriver to keep in your kitchen drawer, and others who will swear that all you need is Harbor Freight tools to repair the Hubble Space Telescope in orbit. Just pick something that is rated for your actual usage and get on with the job.
RPH
Well-known member
How big you want. Lots availability, I used air surge tanks in the search.
finn
Well-known member
I have seen pictures of exploded tanks, but never actually put my eyes on one. I have seen plenty of tanks pulled from service because of pinhole leaks though.
When you do see pictures of an exploded tank, there’s never a complete backstory, either. Rather there’s some sort of National Enquirer headline, but no details. At least one that was circulating had a stuck contactor, which overpressured the tank.
The old Sears homeowner belt drive compressors had tags with the manufacturer’s name, date, etc, and I think a ASME reference. I’m going by memory, though. Mine dates from the early 80s. So does the little 2 hp brown compressor I pulled from the scrap heap. Don’t recall the brand, but it looks a lot older than my Craftsman. (I wanted the motor. I didn’t run it long enough to see if the tank leaks).
The 30 gallon belt driven Kobalt I picked up a year or so ago has a manufacturer’s tag. No ASME notation, though.
When you do see pictures of an exploded tank, there’s never a complete backstory, either. Rather there’s some sort of National Enquirer headline, but no details. At least one that was circulating had a stuck contactor, which overpressured the tank.
The old Sears homeowner belt drive compressors had tags with the manufacturer’s name, date, etc, and I think a ASME reference. I’m going by memory, though. Mine dates from the early 80s. So does the little 2 hp brown compressor I pulled from the scrap heap. Don’t recall the brand, but it looks a lot older than my Craftsman. (I wanted the motor. I didn’t run it long enough to see if the tank leaks).
The 30 gallon belt driven Kobalt I picked up a year or so ago has a manufacturer’s tag. No ASME notation, though.
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I'm pretty sure that a catastrophic explosive tank failure is extremely rare in a consumer grade compressor. It's not like they are running thousands of psi. But I would be interested in any hard data that anyone can provide.
yes, they are rare but not impossible. there's a **** ton of potential energy in a tank with 100+ psi of air pressure . is it really worth risking by taking extra chances ?
If there were major problems with homeowner model compressors, the trial lawyers would crawl out from under every cow chip around looking at collecting money, but in the workplace here in CA, a permit to operate a pressure tank is required & inspected. A tank without the proper label is not going to pass.
This is true. Best to stick with a pressure vessel rated to at least 10,000 psi.
But seriously, if the typical consumer grade tank was actually dangerous, we wouldn't be able to buy them because the lawyers would have killed them. "Rare but not impossible" leads to huddling in your closet hoping that a meteorite doesn't hit you. If explosions of homeowner compressor tanks was actually a thing, there would be billboards along the highways from personal injury attorneys. Don't buy your compressor from a meth head in a pickup, or drag one out of a swamp. And don't use it as a headboard for your bed to power your *** toys, and drain the tank regularly. It'll be safer than driving to church.
I'm not going to keep on with this as there's never going to be an end... there never is.
I agree. most consumer grade cylinders are quite safe... and seldom blow... but, that doesn't mean it would be just as safe for the homeowner to weld a patch on to a leak, or weld in a bung etc etc
I like to use the analogy of; take a kids ballon and blow it up with air. puncture it and see what happens, shrapnel flying everywhere. fill the same balloon with water & puncture it and see what happens .
and I don't buy your 10,000 lbs either. a hundred or less can do a hell of a lot of damage
I agree. most consumer grade cylinders are quite safe... and seldom blow... but, that doesn't mean it would be just as safe for the homeowner to weld a patch on to a leak, or weld in a bung etc etc
I like to use the analogy of; take a kids ballon and blow it up with air. puncture it and see what happens, shrapnel flying everywhere. fill the same balloon with water & puncture it and see what happens .
and I don't buy your 10,000 lbs either. a hundred or less can do a hell of a lot of damage
Yes, 100psi *can* do a lot of damage. But in real life, how often and what are the odds of a Sears or Harbor Freight-grade compressor actually exploding and hurting anyone in reasonably normal use? How does that compare to driving to the grocery store? It's easy to get caught up in "what-ifs" to the point of paralysis. Deflecting to arguments about a homeowner welding on the tank is downright bizarre.
And puncturing a compressed air tank isn't something that happens often enough to count in normal use. You could just as well talk about shooting a propane tank or a transformer on a power pole.
The 10,000 psi pressure vessel comment was in response to your "Is it worth it to take extra chances?" to justify insisting on an ASME tank. A 10kpsi tank isn't necessary or economically appropriate for an occasional use 100psi air tank. Neither is ASME.
If I'm wrong, show me the class action lawsuits.
micromind
Well-known member
I've had 12 gallon non-ASME tanks that I mounted a 3/4HP motor and a single cylinder pump on in my various vans for over 40 years. They always hold pressure, often for days at a time. They run at 110 - 135 PSI......and yes, there's a high pressure relief valve......150 PSI.
After about 30 some years the first one wouldn't hold pressure anymore. So I pumped it up to about 50 PSI and soaped every pipe fitting, no bubbles. Then I felt the bottom with my hands. Sure enough, a pinhole leak at the bottom.
I replaced the tank and bolted all the original stuff on it. 10 years in, no leaks yet.
After I got the old tank out, I hammered the entire bottom of it with the ball end of a ball-peen hammer. It was solid except where the leak was and then only maybe a 1/4" circle wasn't solid but it wasn't soft either.
Drain my tanks often, I think this is key to making any tank last.
After about 30 some years the first one wouldn't hold pressure anymore. So I pumped it up to about 50 PSI and soaped every pipe fitting, no bubbles. Then I felt the bottom with my hands. Sure enough, a pinhole leak at the bottom.
I replaced the tank and bolted all the original stuff on it. 10 years in, no leaks yet.
After I got the old tank out, I hammered the entire bottom of it with the ball end of a ball-peen hammer. It was solid except where the leak was and then only maybe a 1/4" circle wasn't solid but it wasn't soft either.
Drain my tanks often, I think this is key to making any tank last.
Wait, what? How is it you weren't blown to smithereens!
welder4956
Well-known member
Most state pressure vessel laws exempt vessels with a capacity of 5 cu.ft. (37.4 gal.) with 250 psig or less maximum pressure from being ASME stamped vessels. Presumably, because the risk of injury and damage is low with this size limit. For the OP's application (which is a bit dated) I don't see an issue with using non-stamped vessels.
So, I'm not saying you must have an asme tank. I am saying that tanks can be dangerous and should not be repaired etc. treat the pressure vessel with respect .
NFC
NFC
micromind
Well-known member
The tank was intact except for the pinhole leak.
Under NO circumstances would I do or allow welding on a pressure vessel, too scary a thought.
cvairwerks
Well-known member
Welding on pressure vessels is done all the time. It simply tskes some specialized knowledge, skills, procedues and equipment. I grew up learning to read from P&ID's and vessel manufacturing drawings.
Chris_Hamilton
Well-known member
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Of which very few have. Understood that they are repaired but they are done so by skilled tradesman knowledgeable in doing so. For the average guy with a welder, I would still agree with the advice above and say never try to repair a tank.
nadogail
Well-known member
The ASME tag is as important as an UL Label, very desirable but not absolutely necessary.
cvairwerks
Well-known member
Depends on where you are. I grew up where drilling and refining are prevalent. Pressure vessel and piping certified welders outnumbered the non certified guys probably 10:1.