BS EN 969:2009 pdf free download – Ductile iron pipes, fittings, accessories and their joints for gas pipelines – Requirements and test methods.
6.7 Thickness of paint coatings
The dry film thickness of paint coatings shall be measured by either of the three following methods:
directly on the casting by means of suitable gauges, e.g. magnetic, or by using a ‘wet film’ thickness gauge where a correlation between wet film thickness and dry film thickness can be demonstrated; or
— indirectly on a token which is attached to the casting before coating and is used after coating to measure the dry film thickness by mechanical means, e.g. micrometer, or by a weight method similar to 6.6; or
— indirectly on a test plate made of steel or of ductile iron, which is coated by the same process as the castings to be controlled.
For each casting to be controlled at least three measurements shall be taken (either on the casting or on the token). The mean thickness is the average of all the measurements taken and the local minimum thickness is the lowest value of all the measurements taken.
7 Performance test methods
7.1 Leak tightness of flexible joints to positive internal pressure
The test shall be carried out on an assembled joint comprising two pipe sections, each at least 1 m long (see Figure 1).
The test apparatus shall be capable of providing suitable end and lateral restraints whether the joint is in the aligned position, or deflected, or subjected to a shear load. It shall be equipped with a pressure gauge with an error limit3 %.
The vertical force W shall be applied to the spigot by means of a V shaped block with an angle of 1200, located at approximately 0,5 DN in millimetres or 200 mm from the socket face, whichever is the largest: the socket shall bear on a flat support. The vertical force W shall be such that the resultant shear force F across the joint is equal to the value specified in 5.2.3.3, taking into account the mass M of the pipe and the geometry of the test assembly:
a, b and c are as shown in Figure 1.
The air pressure in the test assembly shall be raised steadily until it reaches the test pressure given in 5.2.2. The test pressure shall be kept constant within ± 0,5 bar for at least 2 h during which the joint shall be thoroughly inspected every 15 mm. The leak detection shall be carried out by spraying a suitable foaming agent or by submerging the test assembly in water. All necessary safety precautions shall be taken for the duration of the pressure test.
For a restrained joint, the test assembly, the test apparatus and the test procedure shall be identical except that there shall be no end restraint, so that the axial thrust is taken by the restrained joint under test. In addition, possible axial movement of the spigot shall be measured every 15 min.