Document: NRC Regulatory Guide
Document ID: c361be32-682d-4496-bb9f-6e52a80b0bd9
Document Type: regulatory_guide
Title: Instrument Sensing Lines + HISTORY –HISTORY 01/2019 – DG-1352 , Proposed Revision 2 09/2016 – Periodic Review of Revision 1 – Revise 12/2008 – DG-1178 , Proposed Revision 1 Draft IC 126-5, Proposed Revision 0, published 03/1982 (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1815/ML18158A303.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.151
CFR Part: 
CFR Title: 

Content:
ndards Institute (ANSI)/International Society of Automation (ISA) standard ANSI/ISA 67.02.01-2014, “Nuclear Safety-Related Instrument-Sensing Line Piping and Tubing Standard for Use in Nuclear Power Plants,” (2) identification of the International Organization for Standardization (ISO) standard ISO 2186- 2007, “Fluid Flow in Closed Conduits—Connections for Pressure Signal Transmissions between Primary and Secondary Elements” (Ref. 9), and (3) a reference to recent operating experience, as described in NRC Information Notice (IN) 2013-12, “Improperly Sloped Instrument Sensing Lines,” dated July 3, 2013 (Ref. 10) as it relates to improperly sloped sensing lines. Background The NRC issued Revision 1 of RG 1.151 in July 2010, which endorsed ANSI/ISA-67.02.01-1999 (Ref. 11), with certain clarifying regulatory positions. ANSI/ISA-67.02.01 provides design, physical protection, and installation requirements for safety-related instrument sensing lines, as well as for sampling lines previously covered by ANSI/ISA-S67.10-1994, “Sample-Line Piping and Tubing Standard for Use in Nuclear Power Plants” (Ref. 12). ANSI/ISA-67.02.01 discusses the pressure boundary requirements for sensing lines up to and including one inch (25.4 mm) outside diameter or three-quarter inch nominal pipe 1.050 inch (26.67 mm) outside diameter. The boundaries of this standard for instrument-sensing lines span from the root valve/piping class change up to but not including the manufacturer-supplied instrument connection. The boundaries of this standard for sampling lines span from the process tap to the upstream side of the sample panel, bulkhead fitting, or analyzer shutoff valve, and include in-line sample probes. Recent operating experience has shown that improperly sloped instrument sensing lines are contributing to the degradation of safety-related instrumentation operation. In response, the NRC issued IN 2013-12 to address this operating experience with regard to instrument sensing