PVC pipes in building
The PVC or polyvinyl chloride is the most versatile plastic and the use of PVC pipes in buildings is becoming popular day by day. It is possible to substantially change or modify the properties of PVC resin by the technique of compounding i.e., addition of other additives to PVC.
It is thus possible to prepare a PVC rigid pipe. The other applications to which PVC can be put up include footwear, bottles, gramophone records, waterstops, cables, making toys, bags, tubes, floor coverings, etc.
Precautions taken while design and installation of PVC
- The design of PVC pipes should accommodate adequate provisions in respect of appropriate air vents, etc.
- Fittings such as tees, elbows, caps, etc. use in PVC piping system should be fit well with the pipes. If such fittings are too tight, they will develop stress in the system and if they are loose, they will cause leakage of water through pipe system.
- The PVC pipe system should be suitably test after installation and before putting the system in service.
- Trenches for laying PVC pipes should be as narrow as possible and at the same time, they should be wide enough to allow convenient installations of the pipes.
- Turbulent flow of water through PVC pipes should be avoid.
- They are available in different colours. But it is advisable to avoid red and black colours on external expose walls.
- Provide with sufficient supports and additional supports in the form of hangers, anchor, etc. should be freely use to eliminate external stresses.
- Not be use at places likely to be subject to heavy loading.
- They should not be bent too much to avoid any stresses in them.
Advantages of PVC pipes
- Good insulating properties and hence the temperature of water passing through such pipes is not affect by the outside temperatures.
- Permit high, smooth and undiminished flow of water.
- No problem of incrustation.
- Possess high Hazen Williams Constant and it results into adoption of smaller size of PVC pipes as compare to the sizes of pipes of other conventional materials under similar conditions.
- Prove to be economical as compare to other pipes of conventional materials such as asbestos cement, cast-iron and galvanize iron.
- Provide resistance to a variety of chemicals.
Disadvantages of PVC pipes
- Liable for creep phenomena requiring closer spacing when install above ground level.
- Cannot be use at high temperatures as they are basically thermo-plastic. The recommend range of temperature for pressure applications is -1 degree celsius to + 49 degree celsius and for non-pressure applications, the higher temperature up to 80 degree celsius can be use.
- Do not have the same strength as cast-iron or galvanize iron pipes.
- Possess higher coefficient of expansion as compare to the cast iron or galvanize iron pipes.
It may however be note that the above drawbacks of PVC pipes are not very serious and they are now wide use as pressure pipes for rural water supply, electrical conduits, telephone ducts, tube well castings, etc.