A versatile material, plastic is especially useful for carrying water Plastic pipes are easy to use, lightweight and maintenance-free. Some types designed to withstand high temperatures are now available for hot water and heating systems, but most domestic plastic pipe work is used for taking away waste water, especially in bathrooms.

TYPES OF PLASTIC PIPEWORK

Three types of plastic pipes are used for the water supply and heating installation in your house. chlorinated polyvinyl chloride (CP\/Q, polybutylene (PB), and cross- linked polyethylene (PEX), pipes are tough and versatile enough for use as hot- and cold-water carriers, and also for central-heating systems.

The majority of bathroom waste pipes are made from polypropylene (PP) or acrolonitrate butadiene styrene (ABS for short). waste pipes are 32mm (1 Am), 40mm (1 kin) or 50mm (2 in). They are joined to traps and other components using compression fittings, which contain a flexible sealing ring that makes dismantling for the removal of any blockages an easy task. Correctly fitted, a plastic compression joint should only need to be hand- tightened to create a watertight seal. Polypropylene (PP) pipes are joined together using push-fit connectors, while ABS pipes are solvent-welded.

Check the manufacturer’s instructions with regard to expansion, which occurs in 100mm (4in) diameter soil pipe and may occur in plastic waste pipe carrying hot water over a distance. An expansion coupling, with a push-fit seal at one endto allow movement, may be necessary.

FITTING A PUSH-FIT JOINT

Cut the pipe to lenght using a junior hacksaw

1. Plastic pipe cutters

2. Using a file, chamfer down the outer edge of the pipe

3. Remove any internal burrs using a craft knife

4. then apply a little silicone lubricant

5. Push the pipe into the socket of the fitting, right up to the stop. using a marker pen, mark the pipe, then withdraw the pipe 9mm (3/8in), using the mark you made as a measuring guide

6. This is to allow for expansion caused by hot water.

TOP TIP – To help make a straight cut, wrap some masking tape around the plastic pipe to align with the measured mark.

FITTING A SOLVENT-WELD JOINT

Some pipes are connected using fittings which are welded together with a purpose-made solvent. After fitting the waste run together without the solvent, simply reassemble, applying solvent to the inside of the socket and the outside end of the pipe. As for a push-fit joint, push the cut pipe into the socket to check on the fit, and mark the pipe at the end of the joint with a marker pen. For extra adhesion, use fine sandpaper to key the end of the pipe and the inside of the socket

7. To assist the final positioning when the solvent is applied, mark an alignment line on both socket and pipe. When the solvent has been applied

8. immediately align your marks and push the pipe into the socket with a twist

9. You have to work quickly, as the joint will be cured in about 15 – 20 seconds. It will be ready for use with cold water in about one hour and with hot water in approximately four hours.

TOP TIP – If you follow the instructions, you should have a leak-proof bath waste run. However, if a joint is leaking slightly a repair can be effected by simply applying a touch more solvent to the mouth of the socket to seal the joint by capillary action.

PEX PIPEWORK

We believe the future of plumbing is going to be based on PEX pipes. This plastic pipe is ideal for hot and cold water supplies as well as central-heating systems, particularly under floor heating systems. The PEX system is simple to use and install.

Already popular and successful across the USA and Europe, it is beginning to take off here as well, because it is so reliable yet easy to work with. Without any rubber seals or moving parts, it becomes a uniquely innovative design.

The technique for jointing – by means of purpose-designed plastic socket-type fittings – is straightforward and safe, and without the fire risk associated with using a gas torch for soldering. A series of purpose-made adapters make the PEX system compatible with any existing conventionally piped system.