Polypropylene (PP) is the lightest-weight piping material with very good chemical resistance, even to many organic solvents. It is used extensively for HVAC applications and is available in two classifications, with Type I being the most common. Type I has better rigidity and strength but lower impact resistance than Type II, which has improved toughness over Type I material. In chemical drainage applications, heat stabilizers and flame-retardant additives are added to PP to retard flammability and thermal aging.
PP is also used in many more corrosive and higher temperature applications (180°F) than PVC. Like purple PVC and CPVC, purple PP is being used for non-potable applications. The primary method of joining PP piping systems is through heat fusion, although mechanical joints can also be used. PP pipe is available in standard 20’ lengths in sizes ranging from ½" to 40".
To accommodate different working pressures, PP is available in both schedule 80 and schedule 40. Typical applications include chemical drainage systems, industrial processes, high-purity water systems, hot and cold water distribution, and gravity sewer systems.