When a facility’s hazardous materials piping is assembled with bolted flanged joints, it needs a maintenance procedure to properly assemble and disassemble these flanged joints. Along with this procedure, a means to pressure/leak test the bolted flanged joint must be used to ensure leak tightness. Subject to code/regulatory requirements, the worker should establish:
(a) the type of leak test (e.g., visual, bubble-forming solution, sniffer)
(b) test fluid (e.g., air, inert gas, water, service fluid)
(c) test pressure (e.g., low pressure or up to a codemandated visual inspection pressure)
(d) acceptance criteria (often simply “no detectable leaks”)
Facilities are CAUTIONED to consider that the practice of using “temporary” gaskets for pressure or tightness testing of systems that include bolted flange joint assemblies have resulted in numerous incidents of injury and near injury to assembly personnel due to “blowout” failure of these alternative gasket materials/types.
Using substitute gaskets during testing instead of those designed as the final seal for the joint is NOT recommended.
Refer to ASME PCC-2, Article 501 for general good practices for pressure and tightness testing of pressure equipment.