PVC Polyvinyl Chloride

Perhaps the first thermoplastic to be used in any quantity in industrial applications was PVC. These plastics have grown steadily in favor over the years, primarily because of the ease of fabrication. They are easily worked and can be solvent welded or machined to accommodate fittings. As a consequence, the materials have been used for over 40 years in Europe as house piping and are gaining favor in the USA for this purpose. Piping men accept the properties of the product as being related to a low strength metallic material. However, in the design of a piping structure, the thermal coefficient of expansion must be taken into consideration, and the poor modulus of the material must be considered. With these limitations, the product as a piping material can accommodate a wide range of products found in industry today. Two classes of the primary PVC material are available: normal grade and a high impact grade. The latter is normally used.

In addition to piping, solid valves, and pumps, smaller items of equipment and structures may be obtained of PVDC. Also, the material is available as a rigid or pliable sheet liner for application on the interior of vessels.

Many modifications of PVC can be made. Fiber reinforced products are available. Consequently, it is best to standardize on the use of a national product such as that recognized under the ASTM or Commodity Standards.

The material has an upper temperature limitation of 65 °C for the normal (Type I) and 60 °C for the high impact (Type II) products. The chemical resistance is good in inorganic media with an outstanding resistance to oxidizing agents. However, contamination by solvents of almost all types must be avoided.