Cost to test compressor tank

[Joe Jensen]

I have a 1970s vintage Quincy compressor that I bought and fixed up about 4 years ago. The compressor was installed new at a dentist's office in the 70s and it had an automatic drain valve it was serviced regularly by the original dealer until the dentist retired. I bought it from his son who wanted the compressor but he didn't have 220 in his garage so it sat in his backyard for a few years (not sure how long). The pump meets specs for CFM and pressure. I replaced the pressure release valves, pressure switch, belts, etc. Great compressor and I love it.

The Quincy model 325 pump is mounted to an ASME certified tank but that cert dated in the 70s. The tank seems great. I have an auto drain on it and the floor under the drain has no rust marks from rusty water. I have no reason for concern. Is it possible to have a tank tested and certified? Any idea on the cost? Is it rational to do this?

thanks...joe

[Ray Newman]

Look in the local Yellow Pages under air compressors-repair/rebuild. Call a few shops for recommnedations and an idea as to cost.

[Lee Schierer]

I believe you need to be licensed to test tanks for ASME and it is generally done by filling the tank with water and pressurizing it. Where I used to work we made pressure vessels and the Hartford inspector came by regularly to check our equipment for pressure testing. I know that you used to be able to get propane tanks recertified as they were only good for 10 or 15 years on their original certification.

[Bob Deroeck]

Hi Joe,

Yes, it's rational to have the tank tested. If it fails when at pressure and full of air, the results can be very bad. Do you need it certified for professional, liability reasons or is it only for your peace of mind? If the later, consider testing it yourself. The ASME test when this tank was built was to 1.5 x the maximum operating pressure. The ASME code was modified a few years ago to a lower test pressure, I believe 1.3 x maximum operating pressure, but this number would need to be confirmed.

Testing is relatively straightforward. fill the tank with water until water comes out of the top vent. This will ensure there is no residual air left in the tank. It is important to ensure no air is available within the tank to be compressed, which could cause damage or injury if the tank fails during the hydrotest. Rent a manual hydrotest pump. These start about the size of a grease gun. You don't need one bigger than this. Start pumping and looking for water leaks once you hit the normal operating pressure. If you can get to the test pressure without any leaks developing, you're good to go. If this was my tank, I'd test it to 1.5 x maximum operating pressure. If the tank fails during the test, you can pat yourself on the back for having the foresight to test this old tank. If the tank passes the hydrotest, you can pat yourself on the back for having the foresight to test this old tank and you can use the tank with confidence in it's safety for the next 5 years or so.

Bob

[Bill Space]

Like Bob said...but while I have not tried it, a friend long ago told me he filled his compressor tank with water, put a gauge on it, and used a grease gun to pump grease into it until the internal pressure reached the pressure he needed to satisfy himself that the tank was sound.

Seemed like a reasonable way to do it, relatively cheap, and probably did not require much grease providing that all air was removed first.

Just proposing this as an alternative to renting the right tool to accomplish the job...

Again, I never tried it myself, but probably would if I had an air tank I wanted to check for myself, and only for myself, thinking that any test would be better than no test...

Otherwise get a certified pro to do the test and to certify the result in writing!