PVC piping is commonly employed in the chemical industry.
PVC has excellent chemical resistance to wide range of corrosive fluids.
PVC piping undergoes surface oxidation and embrittlement by exposure to sunlight over a period of time. The color of pipe changes from gray to white. The strength of piping is not reduced, however it becomes more susceptible to impact damage. UV protection can be provided by applying a thick coating of latex paint.
It is possible to heat trace PVC piping to maintain a constant elevated temperature. Electric tracing is recommended. The maximum heat trace temperature should not exceed the pressure temperature rating of the piping system.
Pipe saddle cut from PVC pipe are recommended at support locations. PVC pipe must not rest directly on steel. Supports must be provided on or close to inline items such as valves. PVC piping connected to vibrating equipments such as pumps must be isolated using teflon or rubber expansion joints.
Solvent cementing is a preferred method of joining PVC pipe and fittings. The OD of the pipe and ID of fitting are primed, coated with special cement and joined together. Most solvent cement joints fail due to lack of solvent penetration or inadequate primer application.
|Coeff of |
|in/in °F x 105||0.06||3|
|Modulus of Elasticity @ 73°F||psi x 105||290||4.2|
|Working Stress @ 73°F||psi||20,000||2,000|