Technical Information for
Tube Fittings And Pipe Fittings Material

Test assemblies to be subjected to a pressure of 1.5 times the maximum working pressure of the Fittings applied at the rate of 200 kg/cm2 per minute and maintained at final pressure for five minutes without leak.

Test assemblies successfully completing the Proof Pressure Test above are dis-assembled and assembled twenty five times after which they must pass the Proof Pressure Test.

Apply hydraulic pressure to the test assembly upto a maximum of four times the working pressure at the rate not exceeding 200kg/cm2 per minute and maintain for five minutes without leak.

Test assemblies satisfactorily Proof Pressure Tested are subjected to negative pressure upto 700 mbar and then isolated from the vacuum pump. The assembly must maintain the vacuum for fifteen minutes. The assemblies are suitably decreased before the test and total exhausted volume should not exceed 20% of the total assembly volume. This test can also be given at two temperature for cryogenic applications.

Test assemblies suitably Proof Pressure Tested are connected to a hydraulic pressure impulse and vibration test bench and subjected simultaneously to pressure impulses at 30 to 100 cycles per minute and vibration in two mutually 6 5 perpendicular planes at 1,300 to 2,820 cycles per minute for a minimum of 5 x10 pressure impulses and 20 x10 vibration cycles. The only permissible re-tightening is allowed after the first 1,000 pressure impulses to allow for bedding-in. When subjected to the test described this coupling should not leak in the assembly. Couplings that fail shall be examined for signs of cracking due to fatigue stress.

The above tests have been specified in the standards BS 4368 Part IV:1984. Customers working with high temperatures have specified a temperature cycling test which requires test assemblies to be subjected to suitable temperature cycles and then subjected to the Proof Pressure Test without leakage. Other customers working with gases have specified a 6 helium leak test with leak rates not exceeding 2 x10 STD. CC/SEC.