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Stay away from those old compressors...


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I thought this story important enough to repost. I asked Mike the OP if he minded if I reposted this thread of his to another forum in the past to help spread the word about compressor safety and he gladly gave me his permission to do so so others wouldn't have to go thru what he did. This happened back January of 2011 and Mike has made a ful recovery with minimal if any lingering effects luckily.



Mike is lucky to be alive after what happened when the compressor tank exploded on him.





Stay away from those old compressors if you don't know their history. The pics will tell more than I can type since I only (fortunately) have the use of my dominant right hand. Our son was given an old craftsman 3 hp 220 v. we got him a brad nailer for christmas, so he bought an air hose to try it out. i was hunkered down beside it watching the gauges. when it hit 130 psi i pulled out on the pressure relief to make sure it worked and it did. when it hit 150 psi i was about to lose my nerve and shut it down. then the tank blew, luckily for me, out the bottom. i feel quite fortunate to have survived this.the injuries were: bad laceration on the back of the left hand,all four bones broken where the fingers attach to the hand. left knee took a severe impact from tank spliitting and broke the tibia and femur.amazingly i never lost consciousness and felt a bad pain in the front of my neck. ran my right hand over that area after seeing my left hand and was actually relieved to see no blood in that area. apparently it blew my left hand into my throat.

The docs pinned the four bones together in my hand, put a plate about 8" long on my tibia and ran 4screws into my femur.the ol timex took a liiken and is still tickin, just broke the band pin when it hit my neck.the truly amazing part is my wife,son and his girlfriend and an older friend were in the garage when this happened, nothing happened to them outside of some ringing ears, not a scratch.the fridge next to the compressor was a liitle worse for wear as evidenced in the pics. the little tv behind the compressor had the cabinet half torn off, but the picture tube was still intact.the 16' garage door got one roller knocked out of the track and about 12 sheetrock screws got the mud knocked off them.all in all, i feel lucky i survived it. i guess we all have angels watching over us. i'll let the pics tell the rest.





post-25608-0-90923300-1379612943_thumb.j  post-25608-0-08309900-1379612949_thumb.j  post-25608-0-70841500-1379612951_thumb.j  post-25608-0-85599500-1379612958_thumb.j  post-25608-0-54182100-1379612966_thumb.j





Again I'd like to thank Mike for his permission to repost this back at the time. Here's the original link to his thread for those that might like to read the comments by others at the time...




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Keep in mind this was a relatively small compressor tank, probably 15 or 20 gallon at best from the look. 150 psi isn't all that high and should have been well within the safe working pressure of the tank.


I regularly see guys treat air compressors with  a very chevalier attitude. It's critical to remember a few things about compressors...


Always drain them regularly to prevent water build up and rust that can weaken the tank.

Never monkey around with the presure cut out trying to gain more out of your compressor.

Remember to test your "safety" or OPV to be sure that it hasn't rusted or frozen shut due to moisture etc.

Never weld on compressor tanks unless you are properly trained in pressure vessel welding and the tank is properly hydro tested afterwards.



Also remember that it's generally a bad idea to test containers with air pressure. Even 50 psi is enough to cause serious injury if the container ruptures. Test at 2-5 psi at most and use soap to check for leaks. A better way is to hydro test them instead.



Compressor tank explosions like this are not all that uncommon. Larger ones can and have led to deaths. Not all that far from me a welder was killed when a air tank he repaired  on a concrete truck ruptured when he air tested it. Failure occurred not where he welded it, but elsewhere. Eventually it was determined that the original tank design was faulty, but that wasn't the only issue that lead to his death. That tank failed at only 80 or 90 PSI from what I recall, but the tank was larger.



I'll also add older tires to the list to be careful of. Old dry rotted wheelbarrow tires can blow when filling, especially if you are in the habit of over inflating them so they are rock hard like some people I know.



Most times rust and so on leads to simple pin hole leaks, but in some cases they can lead to catastrophic failure. Use common sense around these things guys.

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I no longer will consider used air tanks unless I can open em up and do through inspection inside the tank. I've had too many tanks that look like new on the outside fail (not with such horrific results) after I've put them to use......

You can see allot of *good looking* tanks at the junk yards....but they are usually there for a good reason....let the buyer beware................Thanks for sharing...... B)

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And if the first article doesn't scare you into action check out these two pictures and information.  I especially like the first picture.


How can an air receiver tank explode?
During operation, deposits of lubricating oil tend to build up in the line supplying compressed air from the compressor cylinder to the air receiver. As the diameter of the supply line decreases, the already high temperature of the compressed air rises further to a point where it is possible for the contaminant to ignite.

Sparks are then carried into the air receiver where oil from the compressor, which is often present as a mixture with air in the air receiver, burns explosively. As the pressure relief valve is not designed for such an event, rupture of the air receiver vessel is likely to occur. In other air compressor accidents, static electricity sparks have also been identified as a source of fires and explosions.




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I would do a test on any unknown tank to double the working pressure, and known tanks I would make sure are tested each year as well.

compressed air has a lot of stored energy and will explosively decompress if given the chance, this is why tanks are hydraulicly rested as there is no stored energy that way and at worst you get a little jet of water when something goes

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Thanks for posting these guys. It's easy to not think about compressor tanks and just expect them to work properly. By the looks of the roof top compressor carcass I'd have to say giving it it's own room might NOT be good enough.


Frosty The Lucky.

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At work we just replaced a horizontal Emglo that was used to maintain the air pressure on a dry sprinkler system. Less than 10 years old, it had a pinhole leak in the bottom midsection. The paint had blister about 3" in diameter, but hadn't cracked or split.


This unit was manually blown down once a month as part of a PM. No water to speak of was ever blown out, just air. It cycled very little, as the system is pretty tight. Oil changed as spec, never had to add oil between changes.


I hauled it home and cut up the tank to make a fire pit. I started by taking a ball peen hammer to the blistered area, listening to the sound difference between a sound spot and the bad spot. Very quickly, a 1/8" hole opened up, and another about 3" away. I used a pocket scewdriver and probed and wiggled at the holes and they didn't get much bigger.


Using a zip wheel I cut it open lengthwise. It had a good inch of oily sludge in the bottom, drain was clear. In the midsection at the bottom there was an area about 6" diameter that was pitted pretty good. No other areas showed signs of trouble.


If anybody's interested, I can post some pics and more details.

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. By the looks of the roof top compressor carcass I'd have to say giving it it's own room might NOT be good enough.




Someone on the other site posted up youtube security footage of a large industrial compressor tank going thru a block wall when it let go. If I remember correctly that one killed someone. I'll have to try and dig out the link when I get back from my trip to Va this weekend.

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Anyone not convinced can search this page, there's a couple of links that take you to another page that shows a picture where it took off the top of a guy's head.  Not for the faint of heart.




I have a 20 yo 33 gallon craftsman that was draining rusty water.  I drained it when I got home today and inspected the bottom.  As Mike found on his, mine also had a spot where the paint was blistered.  Sure enough metal was soft enough to dig a small hole. 


Question I'm wondering is could I get a replacement tank that I can use the 5 hp 240 volt, motor c-mo-3013 & compressor?  I haven't had any problems with it up until now.  I see on ebay replacement 30 gallons horizontal tanks ~$300, though don't want to assume everything would just bolt on seems like it should.  Probably best to ask whoever is selling the replacement, but thought I'd throw it out there, can't afford it yet.  I could also use the motor for a belt grinder, but I'd already picked up one from a treadmill for that.


Next question is does anyone know how thick the tank walls are?  I'm either going to make a firepit out of this one, or a smoker to sell to recover some of the cost for the replacement.

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I'd honestly be really surprised if the walls are that thick. All the ones I cut apart for scrap when I worked at the dive shop ( sister company did commercial compressor work) were much thinner. I'd say 14-16 ga off the top of my head, but I wouldn't rule out 18 ga. These were all heavy duty 3 phase ones for continuous use in industrial settings for the most part. I'd bet the home center ones are even thinner to meet price point.

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Maybe. I can only remember one compressor for a dry sprinkler system and that was in an old furniture store. At the time I wasn't into compressors and stuff. I only remember it because it was always in our way in the warehouse.

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In the US you will find cheapie compressors that are NOT ASME code stamped. They will be thinner. The ASME code stamped tanks require a 1.5 times the code working pressure proof test before stamping.


Above is ls described a commonly held belief that a hydro test will only send a jet of water or spray and the pressure will be gone. Simple fact is that a hydro test is SAFER, BUT not completely safe from explosion. I did high pressure testing for 23 years, at several companies. The company I worked at for 21 years made refrigeration machines, boilers and valves and fittings. We made our own condenser shells as well and very large steam vesseles.

At lower pressures say 100 psi hydro is much much safer than air. BUT unless you remove all of the air, including the bubbles you have a compressible gas in with the liquid.


As pressure rises in water, you have actual compression of the water as well. AS the pressure rise over 5000 psi significant compression occurs and the stored energy is capable of shattering and throwing hunks of vessel. Granted compressor tanks are not usually tested at these pressures, but a nice quart of trapped air in a 30 gallon tank can make for an exciting day if the vessel ruptures. Been there done that.

My hydro test cell had concrete walls and ceiling. AND we put items under a 1/4" plate retention hood as the flying steel chipped up the concrete pretty badly. I have had hunks of .340 by 2.5" tube fly off that were the size of a man's hand, and they made impressive bangs at 19,000psi.


Since tanks are only tested to 1.5 the cold working pressure, I would also advise against the suggested 2 times pressure mentioned above as well.


Everything mechanical has a life, save yours by respecting the useful life of pressure vessels and make them into fire pits, tumblers etc.

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  • 9 months later...

This thread just stopped my search for a second hand compressor dead in its track. I will find someone who can water pressure test these first, add the cost of that to the price of a compressor and see if it is still worth it.

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most tanks at places I have worked here are stamped with the test pressure double what the working pressure is and should be retested each year, large ones have inspection ports, maybe tanks here are thicker than yours and tested better.


lots for home use though are never tested after the original test and kept for years`

a problem I can see is a lot of the cheaper home use compressors are made in china or other countries that I would not be 100% trusting of their tests, if they were done.


it is very important as stated above to get all the air out for a test, I would not test a tank for others to use, only myself.

a tell tale sign of air still in the tank is the spongy feel of the hand pump you are testing it with, a small amount of that can be due to the flexible hose but you should know how much, if spongy dont test until you have found and removed the air and I would consider half a cubic inch to be way too much to go from 0 to 300 PSI.

if you know the piston area in your test pump you can work out how far it travels for a given volume of water and watch when you press the lever


if you dont know what you are doing get a professional in to do it, if others are going to use it get a professional in to do it, if in doubt dont do it

dont use an unknown compressor just because the job needs it, if it fails you may never get the job done, getting a tested compressor may mean the job is late but at least you wont be!

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  • 3 weeks later...

Our compressor in the workshop is tested and certified every 2 years by a licensed certified boiler/pressure vessel inspector.  He then issues a certificate which by law must be exhibited in a frame under clear glass/perspex in close proximity to the pressure vessel it is issued for.  Don't know what the rest of the world does, but that is the lay of the land in NSW Aust.  On the other hand I have been to private home workshops where I have seen multiple 2nd hand air vessels welded together with weld that looks like swiss cheese, using maleable iron fittings (welded), no drain valves, next to the kids trampoline, no pressure gauges etc, and he was running it to 150psi, just like Chinoble powerstation an accident just waiting to happen.  I advised the guy he was likely to qualify for the Darwin award, but he just said, nah its OK and anyway its just 150psi, I suggested he go and feel how much 32psi is by feeling his car tyre and imagine what that would be like it went bang, then times that by 5.

As far as I know he still has that setup and he is still alive, watch this space.



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