Chapter 10 was authored for the first edition by Robert J. Masterson, who covered Subsection NF (Supports). The second and third editions had been updated by Uma S. Bandyopadhyay with the current third edition addressing the changes of the 2007 Code Edition. Robert traced the historical background of this Subsection, which provides a single source of rules for the design, construction, fabrication, and examination of supports for the nuclear industry. Section III, Division 1, Subsection NF was developed to provide rules for the estimated 10,000 piping and component supports existing in a typical nuclear power plant. The criteria and commentary of Chapter 10 provides information on the origin and evolution of design rules and is intended to allow designers, engineers, and fabricators to make better use of Subsection NF. Topics of greatest interest are discussed from both a technical and a historical viewpoint. However, it is not the intent to address every detail associated with the use of Subsection NF.
Subsection NF rules have evolved dramatically over the past 25 years so that today's support rules seldom resemble the original rules of 1973. In Chapter 10, commentary is provided to explain how the criteria are used, the source and technical basis for equations and rationale, and the reasons for change. Robert covers the scope and classification of the types of supports and attachments. Subsection NF contains rules for the material, design, fabrication, examination, testing, and stamping of supports for Classes 1, 2, 3, and MC construction. Robert provides cross-referencing to Subsections NB, NC, ND, NE, and NG, as well as to the B31.1 and B31.3 Codes, and he also addresses 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.
