ISO DIS 20088-3

Description / Abstract: This part of ISO 20088 describes a method for determining the resistance of a Cryogenic Spill Protection (CSP) systems to a cryogenic jet as a result of a pressurised release which does not result in immersion conditions. It is applicable where CSP systems are installed on carbon steel and will be in contact with cryogenic fluids.

A cryogenic jet may be formed upon release from process equipment operating at pressure (e.g., some liquefaction processes utilise 40 - 60 bar operating pressure). Due to high pressure discharge, the cryogenic spillage protection may be compromised by the large momentum combined with extreme cryogenic temperature.

Although the test uses liquid nitrogen (LIN) as the cryogenic liquid, the test described in this standard is representative of a release of LNG, through a 20mm orifice or less, at a release pressure of 6 barg or less, based upon simulated parameters 1 m from the release point. Confidence in this test being representative is based upon a comparison of the expected dynamic pressure of the simulated release in comparison with dynamic pressure from releases in accordance with this part of the ISO 20088 standard.

It should be recognised that it is not practical in this test to cover the whole range of cryogenic process conditions found in real plant conditions; in particular the test does not cover high pressure cryogenic jet releases that may be found in refrigeration circuits and in LNG streams immediately postliquefaction.

LIN is used as the cryogenic medium due to the ability to handle the material at the pressures described in this part of the standard safely. The test condition is run at 8 barg pressure.

Part 1 of the standard covers cryogenic release scenarios which may lead to immersion conditions for steel work protected by cryogenic spill protection as a result of a jet release or low pressure release of LNG or LIN. Part 2 of the standard covers vapour phase exposure conditions as a result of a jet release or low pressure release of LNG or LIN.