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Waste pipe - compression joints

Compression fittings for plastic waste pipes

waste fittingsThe fittings for this system work as the name suggests. Rubber rings are compressed between the fitting and the pipe in such a way as to produce a watertight seal.

Many standard items are of the compression type since they allow for the pipework to be readily dismantled and reassembled. This makes it easy for blockages to be cleared.

The general arrangement is a fitting – trap, bend, etc – with a large plastic nut at both ends, and a rubber ring or washer for each end of the connection.

Cutting plastic waste pipe

cutting plastic pipeEach fitting slides over the waste pipe up to a particular point. When cutting the pipes, be sure to allow for this extra amount to ensure a watertight connection.

The pipe should be cut to length and any burr should be cleaned off with a small file so that the end is smooth. This is particularly important with the inner edge, since the waste water flowing through may well contain debris which will quickly build up to form a blockage around any rough surface.

Connecting the joint

compression waste componentsPlace the large nut over the pipe. Follow this by the rubber ring or washer. If this is tapered, be sure that the taper goes against the fitting side.

Finally, insert the pipe into the fitting and tighten the nut. These fittings are designed to be hand-tightened only. Do not use spanners or pipe grips. The rubber washer is relatively soft and can be perfectly adequately compressed with hand-tightening. If the joint leaks, it is usually because one or the other component is out of line or misplaced, rather than the washer not being compressed enough.

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