Is the phrase \"Test gas for leakage, test liquid for strength\" correct?
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Is the phrase \"Test gas for leakage, test liquid for strength\" correct?
Generally, this is the case: gas molecules are small in diameter, so gas can pass through leaks more easily. Generally, water is used as the medium for pressure testing of pressure vessels and pipelines, and dangerous liquids must not be employed. For gas pipelines with a nominal diameter greater than 500 mm on the pipe rack, since the safety capacity of the pipe rack may be insufficient when using water for pressure testing, air or nitrogen can be used as the medium for pressure testing instead. Since gas pressure testing is much more dangerous than water pressure testing, except where the design drawings specify that a liquid should be used instead for pressure testing along with reliable safety measures, gas shall not be used for pressure testing on any other equipment or pipelines.
When using gas pressure, be sure to pay attention to changes in external temperature, otherwise overpressure can easily occur!