I've got a dilemma. I have two 60 gallon tanks I want to hydrostatic test to make sure they won't explode in our shop. I've watched some build up pressure in their tank to 200PSI with a pressure washer. My question is, can that be done slowly with a garden hose and adapter, or would I definitely need a pressure washer?
I don't know what your experience is with that kind of work but judging by the question you asked you might want to re think the plan. There is more to it than just pumping up the pressure. Are the tanks certified ? Whht kind of containment vessel do you have in case of failure ? Do you have x-ray capability on site ? Pressure vessels in an uncontrolled release of pressure situation are dangerous (BOMBS). In my opinion it's not worth the gamble. Be safe.
Yes, you will need a high pressure pump to do that. You would probably be ahead to have them tested, instead of doing it yourself.
Yep , the advice is don’t try it yourself if you get it wrong they could be s****ing what’s left of you off he roof and walls....
As long as you fill the tank completely with water and then pressurize it, there's no real danger even if it were to crack or develop some leak. Water is incompressible which means its not capable of storing energy like air or other gases can. Its the sudden release of energy that makes "bombs", and since water can't store any significant energy in the form of compression, its a safe test medium. Certified pressure testing is fairly expensive, mostly due to the cost of maintaining the certification, record keeping, and liability insurance requirements. I've never priced it as I've got a test pump, but I've heard several people say on a 60 or 80 gallon tank you're about as well off to just buy a new tank rather than spend what it costs to have a certified shop do a test. You can use a manual pump like this one that's made for pressure testing. https://www.amazon.com/Steel-Dragon...1&refRID=8FCC0HE5ZKGBHD9EAQ0R#customerReviews If the tanks are ASME code tanks then there's a metal tag spot welded to the tank that shows the max working pressure. It may also show the original test pressure as well. Hydrostatic tests for air tanks are typically done at 1.5 times the stamped working pressure. If you look on youtube you can also see how to run up the test pressure with a grease gun or a porta power pump. If you've got a pressure washer then you could use that as well but you have to be really careful that you don't overpressureize the tank since a pressure washer can easily exceed the burst pressure of the tank with the sort of pressure a pressure washer can develop in a matter of a couple seconds. IMO, by the time you buy a good gauge and whatever valve and fittings are necessary to relieve the pressure when the test is done, its simpler and not much more costly to just buy a manual test pump which comes with a gauge and a valve for relieving the pressure once the test is done.
Better to use a hand pump and fill the tank with water first. If you use the pressure washer keep your hand on the switch and stand well back. Standard for steam boilers is working pressure X 2 + 100. In other words if you want to run 200 pounds pressure test at 500. 200X2+100=500.
I've never seen a shop air compressor tank blow up. I have seen them rust through and leak but not blow up. Drain off condensation regularly and they won't rust. I would just use it, if you are going to be using normal pressure like 100PSI.
Thank you! Big misconception about compressors being bombs, that's why you hydrostatic test. I called two hydrostatic testing companies in my area, they sort of laughed and said they only test large industrial equipment or didn't want my business. These tanks are 35 years old, would save thousands if I can use them before I toss them away.
That pump would be good, the advantage to a hand pump is you put on your test gage and stop pumping when you reach the desired pressure.
Oh I see how that works. You pour water in the basin, and pump it slowly. Great reccomendation, always find what I'm looking for on this forum.
When you do this test use a long hose, so you are not next to the tank. Even there is not much chance of a bleve or explosion at 2-300 lbs, things can happen. We tested vessels that had a working pressure of 4500 psi, those can hurt you! Be safe
I have seen tanks that leak thru a small rust pit as you described, and have even plugged them with epoxy and a bolt, but then one day discovered a couple youtube videos of air compressor tanks that exploded, throwing the whole compressor ***embly in the air violently. It appeared that a weld seam came apart instantly when it failed for whatever reason. After personally witnessing a truck tire explosion at less than 80 lbs that shook the whole building and left us mostly deaf for about an hour, luckily it didn't take anyones head off, it shot across the shop and landed in a pile of tires, I have a respect for the great amount of power that can be stored up in a small amount of compressed air. Please play it safe for that one uncommon time where it can be deadly. WHY BE ORDINARY ?
That’s why I told him to use a long hose, even if it’s hydrostatic testing. He is hydroing it so that won’t happen. Just because it didn’t happen the first ten times doesn’t mean it won’t happen the eleventh time. Be careful and live long. Bones
Pour water in the basin? Fill the tank you are going to test, with water, until it is completely full. As stated before, the water is not compressed when pressure is applied against the water it doesn't have the expansive energy that a gas has. That is why water testing (hydro test) is performed. Apply pressure to the tank in a controlled manner, I use a nitrogen tank and regulator because the volume of gas that is introduced against the full tank of water, is small to get the pressure to rise to the test pressure. The test pressure is usually 1.5 to 2 times the maximum operating pressure(MOP) as stated. Make sure a pressure relief valve is installed for normal operation
What you have to understand is “ total force “ pressure is measured in a standard of “PSI” . Why that being said 3 ft diameter cylinder in sq inches is calculated 3.1416x36 = area of a 1 inch wide band of that cylinder . Take that multiply by pressure = equals total force on a 1 inch wide band of the cylinder . That is why when a cylinder explores from air pressure escaping is a bomb . As stated , liquid is not compress-able so there is no excess energy to release after a leak occurs . I have tested and certified many pressure vessels in 35 years of employment as a Stationary Engineer . Most pressure vessels I tested were a factor of 4 . Super Heated dry steam . Just be safe when in question throw it away and buy a new certified tank . Compare the cost of a new tank to your funeral arrangements , it is cost effective to buy new . Sent from my iPhone using The H.A.M.B. mobile app
I ***ume we're talking about your intended use is for compressed air. I don't know where the test pressure stated above is applicable, but ASME certified tanks currently require a test pressure of 1.3 times (formerly 1.5) the "Maximum Allowable Working Pressure". A safety valve must be set at the "MAWP", and be capable of relieving air as rapidly as your compressor can supply it (blocked out during test). The M*** code requires the vessel to be ASME certified, therefore should have an ASME label attached to the tank, which will state the MAWP. I am not aware of any exception in M*** codes for tanks owned by private individuals, as opposed to industrial users. Furthermore, M*** requires a hydro test prior to use of the tank, and a State inspection every two years thereafter. (Talk to someone with an air receiver at a local auto repair shop, to see what's involved.) If you find you're exempt from State rules, you could check with a SCUBA shop to see if you could bring the tanks to them to be tested. If you do the testing, don't use ice cold water, as some steels become brittle at low temps. Also, don't leave cold water in tank under pressure, as the pressure can increase by several times as the water warms up to room temperature. Good luck!
I see that you are in M***achusetts. If you are a commercial operation or business then I would recommend a conversation with a state boiler inspector to see what he recommends. The boiler inspector could help keep you safe and protect yourself as a business owner. If you do the test then maybe hang a tag stating the date & conditions of the test. I am in the same boat with an old compressor tank. My plan is to pull a couple fittings and get a look around inside with a boroscope to see what may exist for corrosion. The bottom of the tank is where condensate collects with the wet area at the bottom drain is where it is most likely to be rusty. The boroscope could give some visibility of the conditions inside the tanks prior to a hydro. If the tanks are older ASME tagged tanks then they likely have some corrosion allowance for added safety. The ASME codes have been down graded so that the amount of corrosion protection is up to the designer or owner to spec. I agree that with previous posts that there is no real history of compressor tanks blowing up but it is prudent to test them if they are getting long in the tooth. My tank is an ASME certified tank but it is 42 years old & has been idle for a couple years so it is going get checked out thoroughly before I start to use it this summer. I was involved with the inspection and repair of pressure vessels & piping. Max pressure for a hydro was normally the the ASME 1.5x max operating pressure. 5X would be destructive for air tanks. If the tank is rated for a higher pressure than the operating temperature that the shop uses then the max operating pressure could be down rated to safely accomodate the shop operating pressures. The pressure relief valve has to be set to protect the tank at the lower pressures. Go to the 1.3x or 1.5x the max working pressure & install a plug where the relief valves are. In effect down rating the the tank & testing it in the range that you work. It is one way of extending the life of the tanks. The boiler inspector could tell you how to tag the tank to reflect the lower max operating pressures & pressure valve settings. I have been retired for the last ten years and not current but the ASME lower test pressure was on the horizon. If the new ASME code is 1.3X instead of 1.5 then the owner can elect to use the lower test pressures. It is best to do all the testing with water as it will pop and not explode. Water does not have stored energy so the tank will rupture and release the water. There is no stored energy as water does not compress to create an "explosion". Still give it respect and some distance. Hold the pressure for a while and watch the gauges. If the water is cold and the air temperature is higher then the water will warm to expand and may push the pressures to high. If the air is colder that the water the the pressure drops and can be mistaken for a leak. Our steam chief & his ***istant toured the inside of the large 600 psi boilers under a hydro looking for leaks. They would not be inside the boilers if there was a risk of an explosion. Pneumatic testing is dangerous and should be avoided if possible as the compressed air is like a loaded spring and if the tank fails then it will be a destructive failure. Pneumatic testing is done at a lot lower pressure in the ASME codes due to the risks.
My question is, can that be done slowly with a garden hose and adapter, or would I definitely need a pressure washer?[/QUOTE] If you could get 200 psi out of your household garden hose I reckon you would have water squirting out all over the neighbourhood.
Glad I found this thread, as I'm using 2 very old tanks in the air system in my shop. Both have been in my possession about 50 years and were used when I got them One is an 80- gallon, the other a 60, and I keep the compressor cutoff switch at 125# and the pop off at just above that. Planning on installing a new compressor pump that I have had for quite awhile sometime this Summer, and that would be a good time to run a test on these tanks, and also another that I have while I'm at it
It is relatively easy to hydrotest the tank yourself with a few fittings and a grease gun. Most grease guns have an NPT fitting for the hose. Connect the grease gun to any convenient connection to the tank. Fill the tank completely with water. You may have to reposition the tank to make sure that you can vent at the very top. Make sure the tank is full of water. Close the vent and start pumping on the grease gun. It will not take many pumps if the tank is absolutely full. Take the pressure up to 125% of the compressors safety release valve setting. If the tank springs a leak, you will get some water on the floor, but no great drama. You may get a bit of grease in the tank.
There is another really easy way to hydrotest the tank, if you can move it outside. Fill the tank completely with water and cap it off. Move the tank to a sunny spot on a bright day. You can then sit in the shade with a beer and watch the pressure gage rise.
if this is an air tank and there is any question of its integrity s**** it , we have a couple tanks on our air system and if the data tags go missing or there appears to be questionable spots they get s****ped , dont be cheap when dealing with a presure vessel fired or unfired
I used to do hydrostatic testing to 4000 psi when I worked offshore. That was on big air systems that operated at 2200psi maximum. We filled the bottles and piping system with water and used a pneumatic powered pump to bring the pressure up. We could get most of the air out, but it was a large system, across several decks, so there was always a bit trapped in there. When you get close to the maximum pressure it can suddenly start to increase very quickly, so be on the ball or you could rapidly overpressure.
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