Service Connections for PE Pipes
Vinidex recommends that only electrofusion or mechanically connected tapping saddles complying with AS/NZS 4129 should be used to provide service connections to PE pipes.
Tapping saddles should not be installed closer than 100mm to one another to prevent reduction in pressure capacity in the pipeline.
Local authority requirements for the maximum hole size that should be drilled in a PE pipe for tapping purposes should be followed. A good rule of thumb is 50 mm or 1/3 of the pipe diameter, whichever is smaller. This does not prevent the connection of larger branch lines via tapping saddles, provided the hole size does not exceed the above requirements and the hydraulic loss through the restricted hole size is acceptable.
For larger branches, a tee is cut-in or an under-pressure cut-in using a flanged offtake clamp made (see below).
Tapping saddles of the mechanical strap type should not be used on curved pipes. Tapping saddles of the saddle fusion or electrofusion type should only be used on the top of curved lines, and not be closer to the end of the pipe than 500mm.
Connection may then be made without loss of the operating service. Alternatively, tapping may be performed on new main lines prior to pressurisation, and entry into service using the same techniques.
The tapping of services directly into the pipe wall by drilling and tapping a thread in the wall material is not recommended in PE pipes. This practice may lead to premature failure of the system.
Flanged Offtake Clamps
Under-pressure cut-in connections to existing PVC pipelines can be made using a flanged offtake clamp and a flanged valve. Using this technique, cut-ins up to and including the size of the host pipe can be achieved. A flanged offtake clamp is attached to the host pipe and a flanged valve installed. A hole is drilled through the valve using specialised equipment. Once the drilling equipment is withdrawn, the valve is closed and the new pipework connected up to the valve. Note that this is a specialised procedure to be undertaken by suitably trained personnel using Water Agency Guidelines and not to be confused with normal under-pressure tapping for providing property service connections.
For the Vinidex range Service Connections for PE pipes, please view our PE Fittings range.