What are the testing requirements for the sanitary pipework?

Testing methods and requirements when testing sanitary pipework, including WWHRS.

All Soil vent and sanitary pipework must be tested upon completion whether WWHRS is present or not. The test method for above ground sanitary pipework differs slightly from foul (below ground) drainage. The requirement for testing is clearly set out in the Building Regulations and can be found in Approved Document H , with further guidance in BS EN 12056. 

When testing above ground pipework, the main stack is capped with bungs and waste traps are filled with water. A manometer and hand pump are connected to one of the bungs and the pressure increased to 38mm water gauge (3.8 Millibar). This pressure should not drop over a 3-minute test period, and every trap should maintain a 25mm water seal. 

A soap solution can be used to identify leaks when the system is under pressure. A smoke test can also be used to identify any leaks, although smoke testing is not recommended for PVC-U pipes. Bear in mind the sensitivity of air testing - minor temperature fluctuations (caused by sun or shade) can cause a pressure drop or increase. Any defects should be rectified before retesting. 

All recoup products can be tested at an increased pressure of 110mm water gauge (11Millibar) if tested alongside the below ground foul drainage but should not be subjected to water testing. 

BS EN 12056 states; 

‘There is no justification for a water test to be applied to the whole of the plumbing system. The part of the system mainly at risk is that below the lowest sanitary appliance, and this may be tested by inserting a test plug in the lower end of the pipe and filling the pipe with water up to the flood level of the lowest sanitary appliance, provided that the static head does not exceed 6m.’