Depending on the age of the property the plumbing systems will have metal or plastic pipes, although it is not uncommon to find both. In the past all hot water pipes were metal but plastic pipes are now widely used.
The most common type of metal pipe in domestic properties is half-hard copper pipe. It can be used for both supplying hot and cold water and to connect the heating system. Copper pipes are available with 15mm (3/8in) and 22mm (3/4in) diameters and sold in 2m and 3m (6ft and 9ft) lengths.
This small tubing is used in micro-bore heating systems and can be bent by hand. Micro-bore piping is sold in 10m and 25m (30ft and 75ft) lengths and comes in a range of diameters, the most common being 8mm and 10mm.
Originally used just for drainage, plastic pipes can now carry the water supply and connect the heating system. Plastic piping is easier to work with as it does not require soldering and has the added advantage of not being prone to a build up of scale in hard water areas.
The main disadvantage of plastic piping is that as it is less rigid than copper, long pipe runs will require more support. There may also be a limit to the level of heat it can withstand, so the pipe's specification should always be checked. Also, plastic pipes should not come into close proximity with the boiler. The 300mm (3ft 1in) of piping running from the boiler should always be copper. Remember that plastic pipes should never be used for gas or oil supplies.
This rigid plastic pipe can be used for both hot and cold water pipes and for waste systems. However, some local authorities restrict its usage as a supply pipe, so it is important to check before installing.
Also known as Hep2O pipe, this is an extremely flexible pipe used for domestic hot and cold water supplies. This type of pipe is joined using Hep2O push-fit joints or with compression joints (ensure the compression joints have a metal support sleeve). PB pipe is sold in either straight lengths or coils.
Drainage pipes are larger than the pipes used for carrying hot and cold water throughout the property. Drainage pipes take wastewater from the property to the main drainage system and are usually 32mm (1 ¼ in) or 40mm (1 ¾ in) or 50mm (2in) in diameter.
Pipes with a 40mm (1 ¾ in) or 50mm (2in) diameter are used for the waste pipes of sinks, baths and shower trays. Washbasins are fitted with a waste pipe with a 32mm (1 ¼ in) diameter. An even smaller pipe with a diameter of 22mm (3/4 in) is recommended for the overflow pipe from cisterns. Pipes for soil stacks are larger with a diameter of 110mm (4 ¼ in).
Brown UPVC pipe with a 110mm (4in) diameter is generally used for underground drainage, whereas grey pipe in the same material and of the same size is used for soil stacks.
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