JCM INDUSTRIES, INC, General Application Information Fittings and Fabrications for High Density Polyethylene Pipe
JCM Products for repairing, connecting and tapping Polyethylene pipe have been tested and evaluated for their suitability and design capability. In each case JCM products have performed satisfactorily in respect to their design application. Test criteria range from short-term for special applications to long-term 1000 hour evaluations with the most common applications. Temperature and pressure cycles are also incorporated to fully address the pipe characteristics and full range of occurrences. Special monitoring equipment is utilized to produce accurate test data and for historical reference. High Density Polyethylene Pipe (HDPE) has several unique characteristics which are taken into consideration in the following guidelines. The disregard of these guidelines and/or the installation instructions supplied with each fitting may cause unsatisfactory results and void the expressed product warranty. HDPE Pipe considered for use must be manufactured to the recommendations set forth in the ANSI/AWWA Standard C906 and complies with criteria in reference to size. HDPE has a high coefficient of thermal expansion and contraction along with a low modulus of elasticity. This sensitivity to pressure and temperature causes HDPE to expand and contract more than traditional water and sewer piping materials. The potential pipe expansion or contraction must be considered when assembling bolt on fittings. HDPE will relax (“creep”) at lower stress levels than other piping materials. Due to these special characteristics, the following parameters should be adhered to when utilizing JCM products for HDPE (ANSI/AWWA C901, C906). • HDPE and bolt-on fitting connections are vulnerable to forces experienced with expansion/contraction of the pipe and require special consideration. Restraint must be considered when joining plain end pipe to ensure against pipe pull out. HDPE is manufactured with a smooth pipe wall surface resulting in a low coefficient of friction that can enable fittings to slide, shift, move, rotate and/or travel on the pipe after installation. JCM products are limited in the tolerance of axial movement of the pipe. • JCM products for HDPE are designed for underground pressurized fluid service and are pressure rated to match the pipe SDR pressure rating or with a maximum service rating of 150 PSI (Temperature 35 o -75 o F/Maximum test pressure limited to rated pipe pressure or fitting, whichever is lower). For above ground applications, contact JCM Industries Technical Services. • Pipe stiffeners must be used when joining, or connecting to, HDPE. Pipe systems must be engineered to prevent movement causing fittings to slide or rotate on the pipe. Cutting HDPE can cause the pipe to ovate or “neck” down and become egg shaped. This pipe movement can interfere with the assembly of bolt on fittings. Thirty years of successful performance has been one of the most stringent proving grounds for JCM products and their application with Polyethylene Pipe. Generally speaking, most common potable water pressure applications utilize HDPE SDR 17 through 11. For applications on thinner wall pipe, special applications, higher pressure ratings and product usage recommendations, please contact JCM. Note: JCM recommends fusion joints as a primary method of connection. When correctly implemented, fused joints are self-restraining and leak proof. In some instances conditions are not conducive to properly fuse the joint per manufacturers’ recommendations. Mechanical fittings to join or repair HDPE are a secondary and limiting choice. The information included on this page is provided to address the known factors when repairing, joining or tapping HDPE with mechanical fittings.
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