High pressure gas cylinders (also called tubes) are certified for continued use once they pass their periodic inspection and test. The previously accepted practice for testing the cylinders was the hydrostatic proof test, known as ‘hydro’, where water is introduced before it is pressurised to the cylinder’s test pressure, commonly one and a half times the operating pressure.
The problems caused by the hydro testing of high pressure gas cylinders in offshore vessels include concerns over safety; the long time required to complete the tests; and the expense. It is now possible for a more sophisticated technique to be deployed. Acoustic emission (AE) testing is claimed to be faster, cheaper and safer. Leading testing and certification authority DNV GL is the first classification society to include AE testing in its rule set, aligning it with a new European Standard for seamless gas cylinders and their periodic inspection and testing (EN 16753), which was introduced in 2016 and incorporates the AE method.
Click this link to view the Offshore Support Journal's white paper, which examines the benefits of AE over hydro testing within the regime of periodic inspections and tests.