PVC Hose Pipes and fittings are immune to nearly all types of corrosion experienced in underground piping systems. Soluble encrusts (such as calcium carbonate) found in some water supplies do not readily precipitate onto the smooth walls of PVC pipes. Since PVC pipe does not corrode, there is no tuberculation caused by corrosion byproducts, and no tuberculation means there is no reduction in flow areas or flow coefficients as PVC piping systems age. The long-term result of PVC pipe’s resistance to tuberculation is reduced cost for operations and maintenance.
Since PVC is a nonconductor, both galvanic and electrochemical effects are non-existent in PVC pipes and fittings. PVC suffers no damage from an attack of normal or corrosive soils and is not affected by sulfuric acid in the concentrations found in sanitary sewer systems. As a result, no linings, coatings, or cathodic protection are required when PVC pipe is used, resulting in cost savings for construction and future maintenance.
Different water and sewer pipe products provide corrosion resistance in varying degrees depending on application and environment. For this reason, corrosion must be considered when piping products are selected. Because corrosive attack can be anticipated in most underground systems, PVC pipe’s corrosion resistance provides considerable savings in the form of reduced operating costs and longer system life.
A pipe system may be subject to a number of aggressive chemical exposures, accidental or otherwise. Resistance of PVC pipe and elastomeric gaskets to attack by chemical agents has been determined through years of research and field experience, demonstrating its ability to endure a broad range of both acidic and caustic environments. In general, PVC piping systems are not adversely affected by chemicals found in typical potable water and sanitary sewer systems.
Factors Affecting Resistance
Chemical reactions can be very complex; there are so many factors affecting the reaction of a piping system to the chemical attack that it is impossible to construct charts to cover all possibilities. Some of the factors affecting chemical resistance are:
- Chemical (or a mixture of chemicals) present
- Concentration of chemicals
- Duration of exposure
- Frequency of exposure
- PVC compound (or elastomeric compound) presents the geometry of the piping system.