When to hydro-test a compressor tank

How often should a tank be tested? The tank appears to be in good condition on the outside. When I drain water there are no signs of rust,and there is no structural damage anywhere.

Is there a standard of how often a tank should be tested?

It depends. As far as I know there is no requirement for or "standard" time period for hydrostatic testing of privately owned tanks in a non-commercial setting. Otherwise, there may or may not be a requirement for periodic formal inspection and certification as defined by local laws. If such is the case, a formal procedure is usually undertaken by an "authorized inspector" under the National Board Inspection Code of the National Board of Boiler and Pressure Vessel Inspectors or some other entity as designated by law. Generally whether to test and when is left up to the discretion of the "authorized inspector" who has to certify that the tank is safe for continued operation.

If this is for your own use only and no local inspection laws apply to you, a typical procedure would be to test with water only to 1.5 times the maximum allowable working pressure (MAWP) as indicated on the ASME plate tack welded to the tank. You could do this whenever you wanted for your own piece of mind. In any event, check your local and state laws on pressure vessels to be sure.

Rod

Maybe you could find something on the OSHA website if nobody here gives you an answer.