(Polypropylene) PP as specified by ASTM D 4101, is a member of the polyolefin family of pure hydrocarbon plastics. Although PP has half the strength of PVC and CPVC, with a design stress of 1,000 psi at 73° F, it may have the most versatile chemical resistance of the thermoplastic materials identified as the sentinels of industrial piping. Consider the fact that there are no known solvents for PP. As a result, it has been the material of choice for drainage of mixed industrial chemicals for over 40 years. As pressure piping, PP has no peers for concentrated acetic acid or hydroxides. It is also suitable for milder solutions of most acids, alkalis, salts, and many organic chemicals, including solvents. The nemeses for PP are strong oxidizers, such as the hypochlorites and higher concentrations of sulfuric, nitric, and hydrofluoric acids. They are Environmental Stress Cracking (ESC) agents for PP, meaning that time-to- failure is a function of the combined variables of concentration and temperature of the fluid and stress in the piping material. Although PP is not recommended for some organic chemicals, such as polar and chlorinated solvents and the aromatics, the concern is permeation through rather than catastrophic damage of the molecular chain.
All polyolefins are severely degraded by ultraviolet (UV) radiation. However, the plastic piping industry recognizes that PP compounds, containing more than 2 1/2% carbon black pigmentation, are adequately UV stabilized to realize an outside service life of more than 25 years. Chemtrol utilizes such a compound to make all piping components for general industrial consumption, particularly for outdoor installations. Because of the high purity and low surface and joint extractables from natural (unpigmented) PP, Chemtrol utilizes an optimum compound to also make piping components for DI water systems. These are intended as an economic alternative to the ultra high purity infrared (IR) butt fusion PVDF systems typically found in the highly sophisticated electronic semi-conductor industry. It has been demonstrated that an appropriately designed serpentine system, constructed by mechanics properly instructed in the heat fusion of socket joints for sanitary piping, can consistently produce water conforming to the quality standards for injectable drugs.
The following Schedule 80 PP fittings are available in all nominal pipe diameters in both black and natural. Please contact customer service for availability: