Document: NRC Regulatory Guide
Document ID: 8e45dce1-e1e7-4415-b1dd-7e2a610e545b
Document Type: regulatory_guide
Title: Fire Protection for Nuclear Power Plants (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2023/ML20231A835.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.189
CFR Part: 
CFR Title: 

Content:
uld be covered with an approved flame-retardant coating and properly derated or be protected by automatic suppression. Although cable coatings have been shown to reduce flame spread, coated cables are considered intervening combustibles when determining the protection requirements of Section III.G.2 of Appendix R to 10 CFR Part 50. Coated cables do not have higher damage thresholds and, therefore, are not equivalent to IEEE 383 or IEEE 1202 cables. In addition, coated cables can and do ignite in fires. Fire-retardant coatings alone may not be credited as equivalent to 1- or 3-hour fire barriers. New reactor fiber optic cable insulation and jacketing should also meet the fire and flame test requirements of IEEE 1202. 4.1.3.2 Raceway/Cable Tray Construction Only metal should be used for cable trays. Only metallic tubing should be used for conduit. Thin-wall metallic tubing should not be used. Flexible metallic tubing should be used only in short lengths to connect components to equipment. Other raceways should be made of noncombustible material. Cable raceways should be used only for cables. 4.1.3.3 Electrical Cable System Fire Detection and Suppression Redundant cable systems important to safety outside the cable spreading room should be separated from each other and from potential fire exposure hazards in nonsafety-related areas by fire barriers with a minimum fire rating of 3 hours to the extent feasible. Those fire areas that contain cable DG-1359, Page 62 trays important to safety should be provided with fire detection. Cable trays should be accessible for manual firefighting, and cables should be designed to allow wetting down with fire suppression water without electrical faulting. Manual hose stations and portable hand extinguishers should be provided. Manual hose standpipe systems may be relied on to provide the primary fire suppression (in lieu of automatic water suppression systems) for cable trays of a single division important to safety that are separated