Plastic pipework

Plastic pipework is used for the conveyance of drinking water, waste water, chemicals, heating fluid and cooling fluids, foodstuffs, ultra-pure liquids, slurries, gases, compressed air and vacuum system applications.

Materials used

UPVC pipe for underground water mains

Material characteristics

ABS (acrylonitrile butadiene styrene)

ABS is used for the conveyance of potable water, slurries and chemicals. Most commonly used for DWV (drain-waste-vent) applications.

UPVC (unplasticized polyvinyl chloride) and CPVC (post chlorinated polyvinyl chloride)

UPVC has excellent chemical resistance across its operating temperature range, with a broad band of operating pressures. Due to its long-term strength characteristics, high stiffness and cost effectiveness, UPVC systems account for a large proportion of plastic piping installations.

CPVC is resistant to many acids, bases, salts, paraffinic hydrocarbons, halogens and alcohols. It is not resistant to solvents, aromatics and some chlorinated hydrocarbons. It can carry higher temperature liquids than pvc.

PB-1 (polybutylene)

PB-1 is used in pressure piping systems for hot and cold potable water, pre-insulated district heating networks, and surface heating and cooling systems. Key properties are weldability, temperature resistance, flexibility and high hydrostatic pressure resistance. One standard type, PB 125, has a minimum required strength (MRS) of 12.5 MPa. It also has low noise transmission, low linear thermal expansion, no corrosion and calcification.

PB-1 piping systems are no longer sold in North America. Market share in Europe and Asia is small but steadily growing. In some markets, e.g. Kuwait, UK, Korea and Spain, PB-1 has a strong position.

PP (polypropylene)

Polypropylene is suitable for use with foodstuffs, potable and ultra pure waters, as well as within the pharmaceutical and chemical industries.

PE (polyethylene)

Polyethylene has been successfully used for the safe conveyance of potable and waste water, hazardous waste, and compressed gases for many years. Two variants are HDPE (high-density polyethylene)[1] and the more heat resistant PEX (cross-linked polyethylene).

PVDF (polyvinylidene fluoride)

PVDF has excellent chemical resistance which means that it is widely used in the chemical industry as a piping system for aggressive liquids.

Components of plastic pressure pipe systems

Pipes, fittings, valves, and accessories make up a plastic pressure pipe system. The range of pipe diameters for each pipe system does vary. However, the size ranges from 12 to 400 mm (0.472 to 15.748 in) and 3⁄8 to 16 in (9.53 to 406.40 mm). Pipes are extruded and are generally available in: 3 m (9.84 ft),4 m (13.12 ft), 5 m (16.40 ft), and 6 m (19.69 ft) straight lengths and 25 m (82.02 ft), 50 m (164.04 ft), 100 m (328.08 ft), and 200 m (656.17 ft) coils for LDPE and HDPE

Pipe fittings are moulded and come in many sizes: tee 90° equal (straight and reducing), tee 45°, cross equal, elbow 90° (straight and reducing), elbow 45°, short radius bend 90° socket/coupler (straight and reducing), union, end caps, reducing bush, and stub, full face, and blanking flanges. Valves are moulded and also come in many types: ball valves (also multiport valve), butterfly valves, spring-, ball-, and swing-check non-return valves, diaphragm valves, knife gate valve, globe valves and pressure relief/reduction valves. Accessories are solvents, cleaners, glues, clips, backing rings, and gaskets.

See also

References

  1. ↑ "HDPE" (PDF). Plastics Pipe Institute. Retrieved 2011-12-29.