Recommendations for Applying Spray Polyurethane Foam Insulation

This technical note, designated as PPI TN-69, provides guidelines for the application of spray polyurethane foam (SPF) insulation around plastic pressure pipes and fittings. The document outlines the importance of proper installation techniques to prevent damage to plastic piping materials due to excessive heat generated during the curing process of SPF. It details the types of plastic materials commonly used in plumbing applications, including CPVC, PEX, and others, and emphasizes the risks associated with high temperatures that can exceed the rated operating limits of these materials. Recommendations include applying SPF in layers to avoid encasing pipes in a thick layer of foam during curing, which can lead to overheating and potential failure of the pipes. The note also addresses the need to ensure that pipes are depressurized before foam application and during the curing process to prevent deformation or bursting. Additional information on chemical compatibility with spray foam insulation is also discussed.