Polyurethane Coatings and Linings for Steel Water Pipe and Fittings
|Publication Date:||20 January 2018|
This standard sets minimum requirements for shop- and field-applied polyurethane coatings and linings used in the water supply industry. Polyurethanes are used for steel water pipe, special sections, welded joints, connections, and fittings for steel water pipelines installed underground or underwater operating under normal conditions.
Coating and lining systems. The coating and lining systems shall consist of an ASTM D16 Type V thermoset, aromatic polyurethane plastic polymer that is the reaction product of diphenylmethane diisocyanate resin and polyol resin, polyamine resin, or a mixture of polyol and polyamine resins. Typically, these systems are solvent free or almost solvent free (less than 10 percent solvent by volume). They are fast setting (cure to handle in less than 30 minutes) and are applied in one coat direct to steel. However, there is a wide variety of polyurethane technologies available on the market that may contain up to 10 percent solvent or are slower setting that also meet the requirements of this standard.
Conditions not described in this standard. The systems described in this standard are not intended for use on pipe that will be bent after the coating system or lining system has been applied.
Maximum temperature. AWWA steel pipe coating and lining standards are written for and based on the service temperature of potable water. Polyurethanes have performed at higher temperatures. Consult the manufacturer for conditions and limitations.
The purpose of this standard is to provide the minimum requirements for polyurethane coating and lining systems for steel water pipe and fittings including materials, surface preparation, testing, handling, and packaging requirements.