Testing a fitted o2 cylinder

peter-h

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peter-h
If you have an unpressurised aircraft which has a fitted o2 system (a friend's Socata TB21 in this case) and the cylinder needs the hydrostatic test, who is authorised to do this test?

I know an A&P is required to remove/install the cylinder but can any company (normally authorised to do hydrostatic testing) test it? They would deliver paperwork certifying the test, but they would not be an FAA Repair Station.

I've been asking around and (fairly obviously) an FAA RS is OK but this aircraft is based outside the USA where FAA RSs are extremely rare.

I have had portable "aviation" o2 cylinders tested and the company doing it says they just need to see the DOT # on the cylinder.

An "overhaul" of the cylinder is something else; this may mean replacing the valve and its o-ring. The cylinder test companies do this too. Is this OK in this case?

If necessary the result could be inspected by an A&P/IA - there is a number of these around here.

Thank you for any input.
 
In the US hydrostatic testing is done by the DoT and in Canada it is Transport Canada. Not that they actually do the testing but they establish the standards and specifications for the regulations. The actual testing is done by testing houses licensed to perform that test.

In the UK I would assume it is also some sort of government ministry that authorizes certain companies to do the test. A good place that may have some info is a local scuba place in Brighton. Since scuba cylinders are also subject to the same regs as other gas cylinders many scuba shops have arrangements with a local hydrostatic test shop already and may be able to accept your single O2 cylinder for testing.
 
A good place that may have some info is a local scuba place in Brighton. Since scuba cylinders are also subject to the same regs as other gas cylinders many scuba shops have arrangements with a local hydrostatic test shop already and may be able to accept your single O2 cylinder for testing.

Scuba, Welding, Fire Extinguisher shops (commercial) - lots of potential resources. Your local mechanic might even know a good shop...
 
I believe that a hydrostatic test of a cylinder requires that the cylinder be removed and taken to the test facility. The cylinder is depresssurized , filled with water and mounted in a second container which is also filled with water and had a sight glass on the top to measure any expansion of the water. The cylinder under test is then pressurized with a high pressure liquid pump to the test pressure of the cylinder. If the walls of the cylinder are weak they will expand and displace the water in the second container, measured by the sight glass.

An inspection on the other hand, requires that the valve be removed and the interior inspected with a borescope, primarily looking for corrosion
 
As mentioned there are several locations to take you bottle to be tested. And depending on the DOT stamped around the neck of the bottle it will tell the shop what to test to. After testing they will stamp a new date in it.

If you contact your local fire extinguisher shop in town they should be able to accomplish this task for you. This is what they do for a living and have the tools and equipment to inspect and clean you bottle if necessary.

There are procedures in AC 43.13-1b Section 9-47 for inspecting oxygen bottles and cleaning them. It will also explain the different DOT stamps on the bottle in Section 9-51 for light weight bottles inspected every 3-years to the heavy bottle inspect every 5-years.

 
As someone else mentioned, scuba, welding, and fire ext shops can do it for you. Some will do it in house, but most send them out. When I had the last one done I called around and I found a fire ext shop that was the cheapest. The scuba shops seemed be the most expensive IIRC.
 
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