Basis of the Fatigue Capacities, Stress Intensification Factors, and Flexibility Factors for High Density Polyethylene Pipe in the ASME Boiler and Pressure Vessel Code, Section III, Division 1

For corroded piping in low temperature systems, such as service water systems in nuclear power plants, replacement of carbon steel pipe with high density polyethylene (HDPE) pipe is a cost-effective solution. Polyethylene pipe can be installed at much lower labor costs than carbon steel pipe and HDPE pipe has a much greater resistance to corrosion. HDPE pipe has been successfully used in non-safety related systems in nuclear power facilities and is commonly used in other industries such as water mains and natural gas pipelines. Via Code Case N-755-1, the ASME Boiler and Pressure Vessel Code (BPVC), Section III, Division 1, currently permits the use of non-metallic HDPE piping in buried safety Class 3 piping systems. This paper presents the basis for the fatigue stress values to be used for HDPE in the ASME BPVC Section III, Division 1, Class 3 Construction. This information was developed based on testing support by the Electric Power Research Institute. Stress Intensification Factors (SIF) and flexibility factors for use in the design and analysis of HDPE piping systems in nuclear safety-related applications will be provided in the Code and the basis of these stress intensification and flexibility factors is provided. This data may also be useful for applications of HDPE pipe in commercial electric power generation facilities and chemical, process, and waste water plants via its possible use in the B31 series piping codes.