Adiabatic Compression

This test involves examining, analyzing and evaluating different oxygen system components (regulators, valves, hoses, etc.) under the conditions they are expected to perform. The adiabatic compression test consists of rapidly impacting the test article with a slug of gas. Temperature increases suddenly due to gas compression, which can ignite the non-metallic materials of the component if their Autogenous Ignition Temperature (AIT) is achieved.

Fast Turn-around

Most of our standard testing can be performed in 2-3 weeks and we also offer expedited testing services, if required.

Failure Analysis Support

Should the unfortunate event of a test article failure occur, WHA offers failure analysis support to help with redesigns using proven design and material selection concepts and to help with successfully meeting the test requirements during re-testing.

For most of the standards that address adiabatic compression testing, the general procedure is as follows: 

Three test sample components shall be exposed, through their inlets, to pressure shocks from industrial oxygen (minimum 99.5% purity: hydrocarbons < 0.001%). The test system shall be capable of pressurizing the test article from ambient to the test pressure in the required time of 20 milliseconds. This rapid pressurization is performed using a special quick-opening valve. The connection tube between the quick opening valve and the component being tested shall be 1000 mm in length and 5 mm in internal diameter.

Before the test is started, the test sample shall be at room temperature. The test pressure shall be 1.2 times the maximum working pressure of the test component. The oxygen shall be heated to 60 ± 3 oC. Each test shall consist of 20 to 60 pressure shocks at intervals of 30 seconds. Each pressure shock is applied for 10 seconds. After each pressure shock, the sample component is brought back to atmospheric pressure. This is performed by operating an upstream vent valve. Between each pressure shock, atmospheric pressure shall be held for at least 3 seconds.

The component shall not burn out during the test. Post-test, the component is disassembled and all internal parts are inspected. Signs of ignition or heat damage are not acceptable.

Typical components that are subjected to adiabatic compression testing include, but are not limited to the following:

Adiabatic compression testing is commonly performed with oxygen, nitrox and nitrous oxide, but could be performed with other gases as well.

List of Standards

AS 3840.1 ISO 7291 EN 14143
AS 4267 CGA E-4 EN 849
ASTM G175 Phase 1 CGA V-9 ISO 10524-1
ISO 10524-2 ISO 10524-3 ISO 2503
BS EN 1797-1:1998 Annex B EN 585 ISO 14113 Annex B
ISO 10297 CGA E-18