Due to the large amount of energy stored in compressed air and the potential hazard of sudden release of this energy, pneumatic test or hydro-pneumatic test should be avoided whenever possible.
Pressure tests of the vessel should always be conducted using water (hydrostatic test).
Pneumatic test or hydro-pneumatic test should only be considered if hydrostatic test has been carefully reviewed and determined not to be feasible.
When a pneumatic test or hydro-pneumatic test is necessary, MOM’s approval is required.
Safety provisions for pneumatic test, such as those found in the code of construction for the pressure vessel, must be considered. To illustrate, under Section VIII Div 1 of the ASME Boiler and Pressure Vessel Code, UG-100 outlines the requirements for pneumatic testing of pressure vessels while Article 501 ASME PCC-2 specifies calculations for safe distance between testing equipment and personnel.
In addition, risk assessment must also be conducted to identify all other related risks and effective control measures must be put in place to mitigate them.
These could include:
- Barricading the affected area and having proper procedures for raising and holding pressures during the test
- Disallowing examination of the equipment when the pressure exceeds SWP or MAWP
- Use of Personal Protective Equipment including the use of face shields during examination