1. Measure the height of the fitting to be inserted into the existing stack. Add 15mm to this height to allow space for the jointing system.
2. Ensure sufficient support is present in the stack both above and below the location to be cut. If there is any doubt as to the support in place, do not begin modification works.
3. Mark locations on pipe stack to be cut.
4. Cut section out of pipe using a cutting disk or rotary grinder.
5. Remove any burrs, cutting dust and other debris paying particular attention to the sealing zones (approximately 50mm either side of the joint locations
6. Cut ends should be coated as per the touch-up procedure. Ensure coating is fully cured before proceeding with modifications
7. Insert exposed ends of pipes into coupling gaskets making sure that the central register in the gasket is firmly seated against the pipe ends.
8. Insert fitting into gap. Make sure that the gasket is correctly seated against the fitting both top and bottom and that the central register of the coupling is firmly seated against the pipe ends.
9. Loosely assemble the coupling halves around the gasket and check alignment of the pipe stack.
10. Tighten bolts in couplings to the recommended torque settings (15Nm for Ductile Iron Couplings). Ensure that each side of the coupling is tightened evenly.
11. Conduct testing of the new joints & fitting to ensure modification has been successful.
Testing of Sanitary Pipework
In accordance with The Building Regulations 2010 – Approved Document H: Drainage and Waste Disposal, clause 1.38:
“Air Tightness. The pipes, fittings and joints should be capable of withstanding an air test of positive pressure of at least 38mm water gauge for at least 3 minutes. Every trap should maintain a water seal of at least 25mm. Smoke testing may be used to identify defects where a water test has failed. Smoke testing is not recommended for PVC-U pipes.”
Testing of Foul Drainage Pipework
In accordance with The Building Regulations 2010 – Approved Document H: Drainage and Waste Disposal, clause 2.61:
“Water Test. For pipes up to 300mm diameter the system should be filled with water up to a depth of 5m above the lowest invert in the test section and a minimum depth of 1m measured at the highest invert in the test section. This may then be left for a period (one hour is generally sufficient) to condition the pipe. The test pressure should be maintained for a period of 30 minutes, by topping up the water level as necessary so that it is within 100mm of the required level throughout the test. The losses per square metre of surface area should not exceed 0.15 litres for test lengths with only pipelines or 0.20 litres for test lengths including pipelines and manholes, or 0.40 litres for tests with only manholes and inspection chambers alone (i.e. no pipelines).”
In accordance with The Building Regulations 2010 – Approved Document H: Drainage and Waste Disposal, clause 2.62:
“Connectivity. Where separate drainage systems are provided (see Approved Document H5), connections should be proven to ensure that they are connected to the correct system.”