| Plastic has replaced traditional materials like lead and | | | | as hospitals, police stations and launderettes. |
| copper in the manufacture of waste pipes. Waste | | | | Installations such as science labs or photographic |
| pipes are the part of the plumbing system that carry | | | | laboratories often need even stronger grades of |
| waste (foul) waster from appliances such as | | | | specialist plastics due to the waste chemicals involved. |
| washbasins, baths and showers, urinals, kitchen sinks, | | | | Waste pipes and fittings come in three sizes, 32mm, |
| washing machines and dishwashers to the soil pipe | | | | 40mm and 50mm. These sizes correspond to the old |
| system. The soil pipe system then in turn connects to | | | | common imperial pipe sizes of inch and a quarter, inch |
| the underground drainage system. | | | | and a half and two inch. Many plumbers still use this |
| There are three types of plastic used in the | | | | terminology when ordering their materials, so it is |
| manufacture of waste pipes. These are PVC | | | | important that staff have an understanding of both |
| (Polyvinyl Chloride), ABS (Acrylonitrile Butadiene | | | | imperial and metric sizes. Pipe manufacture is not |
| Styrene) and Polypropylene. All three systems are | | | | standardised, and most manufacturers produce slightly |
| commonly used in domestic waste systems, whilst | | | | different size variations - 32mm could actually mean |
| PVC is the most commonly used material in | | | | anything from 32mm to 36mm in practice. This means |
| commercial installations. | | | | that not all systems are interchangeable, so if you are |
| Both PVC and ABS waste systems are known as | | | | repairing or extending an existing installation you should |
| "solvent weld" systems. This means that joints are | | | | ideally take a piece of pipe or a fitting to the retailer to |
| made by using a chemical substance (solvent cement) | | | | check that the new fittings will actually fit. If they don't |
| that effectively breaks down the plastic pipe and the | | | | fit, don't worry - most manufacturers make a multi-fit |
| joint or fitting and welds or fuses the two parts into | | | | compression style fitting that enables to you to join |
| one. This makes the joint completely permanent, and | | | | different types of material, including other plastics, lead |
| unable to leak. Polypropylene waste systems are | | | | and copper. |
| joined using push fit fittings that incorporate a rubber | | | | As a rule of thumb, 32mm pipes and fittings are used |
| seal. The simplicity of this system makes it a favourite | | | | in conjunction with washbasins (including vanity basins) |
| for DIY fans, as provided the pipe is cut square and | | | | and some urinals. 40mm is used when connecting to |
| clean and the pipe is correctly inserted, the system is | | | | baths, showers, kitchen sinks and other kitchen |
| easy to assemble. It can also be taken apart and | | | | appliances such as washing machines and |
| re-assembled if some adjustment in the waste pipe | | | | dishwashers. Some urinals also have 40mm outlets. |
| installation is required. | | | | 50mm pipes are generally used when a number of |
| All three systems are designed to cope with the | | | | appliances use the same waste pipe to join to the soil |
| rigours of the domestic waste system. PVC has the | | | | system, for example in a public convenience where a |
| best resistance to extremes of temperature, acids and | | | | number of urinals are connected in series to a |
| other chemicals and hence this is the material that is | | | | common pipe. |
| usually specified for more commercial installations such | | | | |