Technical Basis for Code Case N-806, Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench

This paper presents the technical basis for Code Case N-806, Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-filled Trench – Section XI, Division 1. This Code Case has been prepared in the ASME Section XI Task Group on Evaluation Procedures for Degraded Buried Pipe. It addresses the nuclear industry need for evaluation procedures and acceptance criteria for the disposition of metal loss that may be discovered during the inspection of piping buried in a back-filled trench.This paper provides background discussion, scope of the Code Case, key definitions and a summary of Code Case methods followed by the basis explanation where necessary. It is organized to follow the same structure as the Code Case for ease of use.Copyright © 2012 by ASME