Plastic Waste Pipe Compression Joints - How to Use Plastic Compression Joints to Join Waste Pipes

Summary: Plastic waste compression joints used in plumbing in the kitchen and bathroom. In this project guide we discuss plastic compression waste pipe fittings and show you the different types of fitting available and also how you can use them to join plastic pipework together.

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Benefits of Using Plastic Compression Waste Fittings

Plastic compression wastes are not used a great deal by plumbers who prefer to use solvent weld waste systems. However the waste pipes used for push fit fittings and solvent weld fittings are two entirely different sizes and one of the easiest ways to join the two is by using compression fittings.

The other really invaluable use for plastic compression plumbing fittings is when you are refurbishing and trying to join old pipes to new pipes including old lead wastes (which should be replaced if you get the chance) and odd sized imperial waste plumbing pipework.

Compression fittings are big and bulky but they are very easy to use and can get you out of some tight spots sometimes. The image below shows the most commonly used plastic compression fittings.

How to Fit Plastic Compression Waste Fittings

To fit a compression waste fitting could not be simpler:

  • Push the pipe you are joining onto into the compression fitting until it hits the stop within the fitting and screw the compression cap as tight as you can
  • This action will force the rubber washer to close tightly round the pipe to produce a water tight joint

Compression fittings are made mostly to use with 32mm or 40mm pipe work.

Selection of Common plastic compression fittings

Selection of Common plastic compression fittings

From left to right the fittings are:

  • Compression waste conversion bend. This bend allows you to change direction and convert from 40mm pipework to 32mm pipework and vice-versa
  • Flexible waste straight coupling allowing you to join two pipes from 38mm to 45mm and absolutely ideal in a conversion or renovation situation. This fitting is also available to convert from 30mm to 38mm and can be bought as a flexible bend from 40mm to 48mm.
  • This is a compression waste reducer fitting which will take pipes sizes from 40mm to 32mm
  • Compression waste adjustable bend taking two pipes of the same size (32 or 40mm) round from a straight line up to 90 degrees. Again, invaluable in a conversion or renovation situation.
  • A compression straight coupling, joining two pipes of the same size in a straight line. 32mm and 40mm
  • A fitting which will allow to you connect a 32 or 40mm pipe round a wide bend to another sized pipe.

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