BS EN ISO 3459:2015 pdf – Plastic piping systems — Mechanical joints between fittings and pressure pipes — Test method for leaktightness under negative pressure
1 Scope This International Standard specifies two methods of testing for checking the leaktightness of assembled joints between mechanical fittings and plastic pressure pipes up to and including 63 mm. The test applies regardless of the design and material of the fitting used for jointing plastics pipe. This test method is not applicable to fusion-welded joints. 2 Principle Checking of the leaktightness of an assembled joint when submitted to external pressure greater than the pressure within the pipe. For measurements where the external hydraulic pressure is greater than the atmospheric pressure within the pipe, procedure A shall be used. For measurements with vacuum inside the pipe segment and an atmospheric pressure outside the pipe, procedure B shall be used. 3 Test parameters and requirements The test parameters of the standard which refers to this test standard shall be used and the requirements shall be fulfilled. If one or more parameters are not given in the referring International Standard, the ones given in Annex A shall apply. The following test parameters should be given by the standard which refers to this test standard: a) test medium; b) test pressure (bar or MPa); c) test duration (h); d) test temperature (°C); e) free length (mm). 4 Apparatus 4.1 Apparatus for procedure A 4.1.1 A suitable apparatus for procedure A is shown in Figure 1.
4.1.2 Enclosed tank, capable of being used at the appropriate test pressure and receiving the test specimen. The ends of the test specimen shall pass through the walls of the tank, so that the inside of the pipe is open to the atmosphere and the connecting pipes are in axial alignment. The assembly shall be arranged so as to enable any leakage to be detected within the test specimen. 4.1.3 Pressure source, connected to the tank and capable of raising and maintaining the specified water pressure with an accuracy of ±0,05 bar. 4.1.4 Pressure measuring device, capable of checking conformity of the test pressure. 4.1.5 Temperature control system, capable of maintaining the temperature of the pressurized water in the tank at the specified temperature, T, with an accuracy of ±2 °C.
5 Test pieces The test specimen shall consist of one or more fittings and two or more pieces of plastic pressure pipe of the size and quality for which the fitting is designed. The fittings and pipes shall not be tested until 24 h after their production. For practical reasons, the manufacturer may wait for a shorter period of time before testing. In case of dispute, a duration of 24 h shall apply. In case of using procedure B, the test piece shall be connected to the vacuum source (pump) via a line with a shut-off valve. The vacuum pressure measurement device shall be connected between the shut- off valve and the test piece. The assembly of the joint should be carried out in accordance with the manufacturer’s instructions. The mean outside diameter, d em , of the pipe should preferably conform to the minimum specified value, and the fitting dimensions (mean inside diameter, d im ) should preferably conform to the maximum values stated by the manufacturer, in order to have dimensions as close as possible to the extreme limits of their relevant tolerances.
6.2 Remove any condensation from the inside of the test specimen. Wait for 10 min and ensure that the inside of the test specimen is completely dry. 6.3 After conditioning, progressively and smoothly apply a first test pressure, p 1 , in the shortest time practicable for at least 1 h and then smoothly increase the pressure without shock to the second level, p 2 . Maintain the test pressure, p 2 , for a further period of at least 1 h. The test starts on achieving the required test pressures. 6.4 Maintain a constant reading on the pressure measuring device. Inspect the inside surface of the test piece for leakage and record any signs of leakage observed, and the pressure at which leakage occurs, while the joint is subjected to external pressure.