6.3.3 Acceptance criteria No leakag

6.3.3 Acceptance criteria No leakage from the tested parts as defined in 6.3.1 is accepted. 6.3.4 Safety requirements Water of suitable purity shall normally be used as the test medium. Where other liquids are used, additional precautions may be necessary. Valve bodies shall be properly vented to remove entrapped air. If materials which are liable to failure by brittle fracture are incorporated in that part of the safety valve which is to be hydrostatically tested, then both the safety valve, or part thereof, and the testing medium shall be at a sufficient temperature to prevent the possibility of such failure. No valve or part thereof undergoing pressure testing shall be subjected to any form of shock loading, for example hammer testing. 6.4 Pneumatic testing 6.4.1 Application and duration of test Pressure testing with air or other suitable gas should be avoided but may be carried out in place of the standard shell hydrostatic test with the agreement of all parties involved in the following cases: a) valves of such design and construction that make it not practicable for them to be filled with liquid; and/or b) valves that are to be used in service where even small traces of water cannot be tolerated. The portions of the valve to be tested, test pressure and duration of application shall be as specified in 6.3. 6.4.2 Safety requirements The hazards involved in pneumatic pressure testing shall be considered and adequate precautions taken.