Section 8 Hydraulic tests on pipes and fittings

8.1.1 All Class I and II pipes and their associated fittings are to be tested by hydraulic pressure to the Surveyor’s satisfaction. Further, all steam, feed, compressed air and fuel oil pipes, together with their fittings, are to be similarly tested where the design pressure is greater than 0,7 MPa. The test is to be carried out after completion of manufacture and before installation on board and, where applicable, before insulating and coating. An exception is made for carbon steel steam heating coils for cargo and slop tanks that are subjected to hot dip coating using zinc or aluminum which may be subjected to hydraulic testing after the application of the coatings.

8.1.2 Where the design temperature does not exceed 300°C, the test pressure is to be 1,5 times the design pressure, as defined in Pt 5, Ch 12, 1.4 Design pressure.

8.1.3 Where testing of systems or sub-systems following final assembly is specified, in addition to the requirements of Pt 5, Ch 12, 8.1 Hydraulic tests before installation on board 8.1.2the lowest applicable pressure as defined in this sub- Section is to be used for testing.

8.1.4 For steel pipes and integral fittings for use in systems where the design temperature exceeds 300°C, the test pressure is to be as follows:

1. For carbon and carbon-manganese steel pipes, the test pressure is to be twice the design pressure, as defined in Pt 5, Ch 12, 1.4 Design pressure.

2. For alloy steel pipes, the test pressure is to be determined by the following formula, but need not exceed 2p:

   

   	=	where p t, and p are as defined in Pt 5, Ch 12, 1.3 Design symbols 1.3.2
   σ	=	permissible stress for the design temperature, in N/mm2, as stated in Table 12.2.2 Alloy steel pipes.
   σ100	=	permissible stress for 100°C, in N/mm2, as stated in Table 12.2.2 Alloy steel pipes.

8.1.5 Where alloy steels not included in Table 12.2.2 Alloy steel pipes are used, the permissible stresses will be specially considered, as indicated in Pt 5, Ch 12, 2.2 Wrought steel pipes and bends 2.2.2.

8.1.6 Consideration will be given to the reduction of the test pressure to not less than 1,5p, where it is necessary to avoid excessive stress in way of bends, branches, etc.

8.1.7 Valves and fittings non-integral with the piping system, intended for Classes I and II, are to be tested in accordance with recognised standards, but to not less than 1,5 times the design pressure. Where design features are such that modifications to the test requirements are necessary, alternative proposals for hydraulic tests are to be submitted for special consideration.

8.1.8 For requirements relating to valves and cocks intended to be fitted on the ship's side below the load water line, see Pt 5, Ch 13, 2.5 Ship-side valves and fittings (other than those on scuppers and sanitary discharges) 2.5.10.

8.1.9 In no case is the membrane stress to exceed 90 per cent of the yield stress at the testing temperature.

8.2.1 Heating coils in tanks, gas fuel and fuel oil piping are to be tested by hydraulic pressure, after installation on board, to 1,5 times the design pressure but in no case to less than 0,4 MPa.

8.2.2 Where pipes specified in Pt 5, Ch 12, 8.1 Hydraulic tests before installation on board 8.1.1 are butt welded together during assembly on board, they are to be tested by hydraulic pressure in accordance with the requirements of Pt 5, Ch 12, 8.1 Hydraulic tests before installation on board after welding. The pipe lengths may be insulated, except in way of the joints made during installation and before the hydraulic test is carried out.

8.2.3 The hydraulic test required by Pt 5, Ch 12, 8.2 Testing after assembly on board 8.2.2 may be omitted provided non-destructive tests by ultrasonic or radiographic methods are carried out on the entire circumference of all butt welds with satisfactory results. Where ultrasonic tests have been carried out, the manufacturer is to provide the Surveyor with a signed statement confirming that ultrasonic examination has been carried out by an approved operator and that there were no indications of defects which could be expected to have a prejudicial effect on the service performance of the piping.

8.2.4 Where bilge pipes are accepted in way of double bottom tanks or deep tanks, see Pt 5, Ch 13, 7.9 Bilge pipes in way of double bottom tanks and Pt 5, Ch 13, 7.10 Bilge pipes in way of deep tanks, the pipes after fitting are to be tested by hydraulic pressure to the same pressure as the tanks through which they pass.