10 Subsection NF—Supports

ASME Boiler and Pressure Vessel Code Section III, Division 1, Subsection NF, was developed in an attempt to provide rules for the estimated 10,000 piping and component supports existing in a typical nuclear power plant. This chapter provides information on the origins and evolution of design rules and is intended to allow designers, engineers, and fabricators to make better use of Subsection NF of the ASME Code. It begins with an introduction to Article NF-1000, focusing on the scope, types of supports, and boundaries of jurisdiction for supports. The chapter then describes the NF-2000 material requirements, providing information on permitted and exempt materials, material certification requirements, and impact testing of materials. Next, it discusses the design rules for supports—both plate-and-shell and linear. All aspects of design are considered, including stress theory, loadings, welding, bolting, load testing, and functional requirements. The chapter then addresses rules for NF-4000 fabrication and installation. These rules provide requirements for the entire fabrication cycle, including forming, fitting, aligning, welding, heat treatment, and bolted connections. The chapter also describes methods for nondestructive examination of support welds and relevant acceptance standards. It provides cross-referencing to Subsections NB, NC, ND, NE, and NG, as well as to the B31.1 and B31.3 Codes. The closing pages of this chapter address Code Cases and Interpretations. Discussions include Subsection NF Appendices, and with the help of Figures, Tables, and references, it is anticipated that the reader will develop a better understanding of Subsection NF and appreciate its complexities and usefulness.