Plastic Cement Welding & PVC Welding

Welding solvents for ABS, CPVC, and PVC plastics are allowed higher VOC content than the 250g/L limit stipulated for cements used to weld other types of plastic. Read the definition in SCAQMD-1168: PLASTIC CEMENT WELDING is the use of adhesives made of resins and solvents which are used to dissolve the surfaces of plastic, except ABS, CPVC, and PVC plastic, to form a bond between mating surfaces.

The data sheet that you posted classifies the product as a “Solvent Cement for PVC Plastic Pipe.” Since the cement is intended for PVC, the manufacturer has correctly classified it as a “PVC Welding” product with a 510g/L VOC limit. A similar product that is not intended for ABS, CPVC, or PVC would meet the definition of a “Plastic Cement Welding” product with a 250g/L VOC limit. ABS, CPVC, & PVC are all types of plastics typically joined by “Solvent Welding.” SCAQMD assigns a different VOC limit to the cements & solvents used to weld each of these 3 types. The “Plastic Cement Welding” category is a fourth category for cements & solvents used to weld OTHER types of plastic.

LS — I see why you are confused. Some flooring systems use a thermoplastic “welding rod” that is inserted into seams and heated to bond adjacent sheets. This is not the type of “welding” that SCAQMD is referring to in its PVC, CPVC, ABS, & Plastic “Welding” categories. The SCAQMD categories refer to solvents & cements like those used to join plastic piping and conduit. See the following SCAQMD-1168 definition: SOLVENT WELDING is the softening of the surfaces of two substrates by wetting them with solvents and/or adhesives, and joining them together through a chemical and/or physical reaction(s) to form a fused union. Also look at the “Plastic Cement Welding” definition posted above.