Here are just some of the common types of plastic pipes you’ll see in a house:
Acrylonitrile Butadiene Styrene (ABS) — ABS pipe is black rigid, non-pressurized plastic pipe used to drain your sinks, tubs, showers, toilet and washing machines. It is also used to vent the drain and waste pipes. To remember its name I call it the All Black Stuff (ABS).
The main disadvantages of ABS are its poor solvent and fatigue resistance, high smoke evolution on combustion, poor bearing properties (high coefficient of friction and rapid wear) and poor UV resistance, unless protected. The material is resistant to water, aqueous salt and acid solutions, and oils but is unsuitable for use with many organic materials and oxidizing acids. ABS is used in preference to PVC for manufacture of pipe for use at high (50oC-65oC) or low (<-20oC) temperatures. It is also used in a variety of equipment housings, and toys. In very general terms ABS can be considered as a stiffer version of polypropylene.
Chlorinated Polyvinyl Chloride (CPVC) — A rigid, high-strength thermoplastic polymer (polyvinyl dichloride) that is practically inert toward water, inorganic reagents, hydrocarbons, and alcohols over a broad temperature range. Commonly used for pipes and pipe fittings.
CPVC is a slightly yellow plastic pipe used inside homes. It will last a long time though not quite as tough as copper. Some areas with corrosive water will benefit by the use of CPVC piping. CPVC tubing is intended and recommended for use in hot and cold potable water distribution systems as well as hydronic radiant heating systems.
Cross-linked polyethylene (PEX / XLPE) – is a form of polyethylene with cross-links. Used predominantly in hydronic radiant heating systems, domestic water piping, insulation for high voltage electrical cables, natural gas and offshore oil applications, chemical transportation, and transportation of sewage and slurries. Recently, it has become a viable alternative to polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC) or copper pipe for use as residential water pipes.
Polyethylene (PE) — A tough thermoplastic polymer of ethylene that resists chemicals and absorbs very little moisture. Polyethylene can vary from soft and flexible to hard and rigid depending on the pressures and catalysts used during manufacturing. It has numerous applications, commonly being used for tubing and piping, food packaging, garment bags, and moulded plastic products.
Polybutylene (PB) — A thermoplastic polymer — manufactured in various degrees of elasticity, strength, and stability. Used for films, coatings, pipes, tubing, fittings, and many other services.
PB pipe is a soft, non-rigid, plastic pipe. It is sometimes curved, usually grey (or possibly silver or black) plastic pipe used in drinking water supply plumbing. When used in the underground service from the water utility company, PB pipe is blue, grey or black. PB pipe is not used for drains, waste or vent piping.
Polyvinyl Chloride (PVC) — A thermoplastic polymer resin material that is rigid and practically chemically inert. Commonly used for water pipes and fittings, as well as numerous other applications such as siding, gutters, raincoats, chemical containers, flooring, toys, tennis court surfaces, and films and package coatings for food containers.
PVC is a white plastic pipe used outside. It can be used only for cold water. Its uses include water services, between the meter and building, and for irrigation.
Virgin PVC is cheap, inherently flame-retardant, stiff and strong with good vapour barrier properties and UV resistance. PVC is stable in contact with inorganic chemicals, including aqueous alkalis and acids. It is unaffected by exposure to oils and alcohol’s but is degraded by most polar aromatic hydrocarbons. Un-plasticised grades (PVC-U) are used extensively (exclusively in some cases) for drainpipes, cold water pipes, guttering, and for window profiles.