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Coverage of Non-Metals in the ASME B31.3 Chemical Plant and Petroleum Refinery Piping Code

The chemical and petrochemical industries have decades of experience in specifying metallic piping lined with non-metals as a cost effective alternative to high-priced alloy materials of construction for piping in corrosive service. Early on, application of plastic piping was essentially limited to atmospheric chemical sewage service and to above-ground vents and drains. However, applications and usage of plastic piping continue to increase as engineers become more confident in specifying plastic materials and mechanical contractors gain experience with their installation. Non-metallic materials are being developed that are not only corrosion resistant but also have increasingly higher pressure and temperature capabilities. Plastic double-containment piping has experienced tremendous growth for handling hazards and toxic fluids. In the United States, recent dramatic growth of plastic double-containment piping applications has been, to a large extent, for compliance with the Environmental Protection Agency (EPA) regulations of the 1976 Resource Conservation and Recovery Act (RCRA). Related EPA regulatory efforts were accelerated in 1988 by more stringent amendments to this legislation. Industry in the United States must comply with these EPA regulations by December 1998. Plastic piping and metallic piping lined with non-metals have been covered to some extent by the ASME B31.3 Chemical Plant and Petroleum Refinery Piping Code for several years. The distinctive requirements of non-metallic piping and piping lined with non-metals were incorporated into the 1980 edition as a separate Chapter VII, which is dedicated to this growing area of interest in piping. This paper provides an overview of the present coverage of non-metallic piping lined with non-metals in the ASME B31.3 Chemical Plant and Petroleum Refinery Piping Code (1). Some topics that warrant further investigation are presented as well.