Document: NRC Regulatory Guide
Document ID: 80776ca5-a83d-4667-9a94-0bffa1befa91
Document Type: regulatory_guide
Title: Fire Protection Guidelines for Nuclear Power Plants (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A013.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.120
CFR Part: 
CFR Title: 

Content:
ould only be used in short lengths to connect to equipment. Other raceways should be made of noncombustible material. (2) Redundant safety-related cable systems outside the cable spreading room.should be separated from each other and from potential fire exposure hazards in non-safety-related areas by fire barriers with a minimum fire rating of three hours. These cable trays should be provided with continuous line-type heat detectors and should be accessible for manual firefighting. 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. Safety- related equipment in the vicinity of such cable trays that does not itself require fixed water suppression systems but is subject to unacceptable damage from water should be protected. 1.120-11 Safety-related cable trays of a single division that are separated from redundant divisions by a fire barrier with a minimum rating of 3 hours and are normally accessible for manual firefighting should be protected from the effects of a potential exposure fire by providing automatic water suppression in the area where such a fire could occur. Automatic area protection, where provided, should consider cable tray arrangements and possible transient combustibles to ensure adequate water coverage for areas that could present an exposure hazard to the cable system. Manual hose standpipe systems may be relied upon to provide the primary fire suppression (in lieu of automatic water suppression systems) for safety-related cable trays of a single division that are separated from redundant safety divisions by a fire barrier with a minimum rating of 3 hours and are normally accessible for manual firefighting if all of the following conditions are met: # (a) The number of equivalent2 standard 24-inch-wide cable trays (both safety- related and non-safety-related) in a given fire area is six or less; (b) The cabling does not