What is PVC?
PVC (polyvinyl chloride) is a thermoplastic used on a huge scale in construction, from waste and drainage pipes to window frames and floor coverings. It comes in two main forms: rigid PVC and flexible PVC.
Rigid and flexible PVC
| Type | Feature | Uses |
|---|---|---|
| Rigid PVC (PVC-U, uPVC) | No plasticisers; stiff and strong | Soil and waste pipes, underground drainage, rainwater goods, pressure pipes, electrical conduit, uPVC windows, gutters |
| Flexible PVC (PVC-P) | Contains plasticisers; pliable | Floor coverings, roofing membranes and films, cable insulation, hoses |
Properties
- Durable and rot-proof, resistant to many chemicals
- Light, easy to cut and solvent-weld
- Expands considerably with heat: roughly 0.06 to 0.08 mm per metre per degree. A 5 m pipe that sees a 40 degree temperature swing changes length by 12 to 16 mm.
- Becomes brittle in the cold. Don’t knock or strike PVC pipes in frost.
- UV exposure: standard PVC pipes are not intended for long-term sunlight unless the manufacturer says so.
Working tips for PVC waste pipe
- Cut square, deburr inside and out, and slightly chamfer the outer edge.
- Check the socket depth and mark it on the pipe.
- Clean both parts with PVC cleaner and let them dry.
- Apply solvent cement to pipe and socket, push fully home to the mark immediately, and leave the joint undisturbed for the time stated on the tin.
- Allow for expansion. On long runs use expansion couplers or ring-seal sockets, and fix clips so the pipe can move.
- Lay drainage to a fall as required by regulations and the pipe manufacturer.
- Colours vary by use: in the UK, below-ground drainage is typically terracotta-brown, while above-ground soil and waste pipes come in grey, white or black.
Health, fire and environment
- Never burn PVC. Combustion releases hydrochloric acid fumes among other things.
- Old flexible PVC may contain plasticisers that are now restricted under EU and UK chemicals rules.
- Recycling: keep PVC waste separate from other construction waste and take it to a recycling centre or waste contractor. PVC recycles well mechanically.
Related terms
- Plastics
- Pressure pipe
- Soil vent pipe
- Stoneware pipe
- Linoleum
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