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:
or access routes to areas containing equipment necessary for safeshutdown should be enclosed in masonry or concrete towers with a minimum fire rating of two hours and self-closing Class B fire doors. (12) Fire exit routes should be clearly marked. b. Control of Combustibles (1) Safety-related systems should be isolated or separated from combustible materials. -When this is not possible because of the nature of the safety system or the combustible material, automatic fire suppression should be provided to limit the consequences of a fire. h. (2) Use and storage of compressed gases (especially oxygen and flammable gases) inside buildings housing safety-related equipment should be controlled. Bulk storage of flammable gas should not be permitted inside structures housing safety-related equipment and should be suffi- ciently remote that a fire or explosion will not adversely affect any safety-related systems or equipment (see NFPA 6, "Industrial Fire Loss Prevention"). (3) It is recognized that halogenated compounds are used to improve the fire retardancy of cable insulation; insulating and jacketing materials should be chosen to have a high flame resistance and low smoke and offgas characteristics without degrading the required electrical and physical properties. However, plastic materials should not be used for other applications unless suitable noncombustible materials are not available. (4) Storage and usage of flammable liquids should, as a minimum, comply with the requirements of NFPA 30, "Flammable and Combustible Liquids Code." c. Electrical Cable Construction. Cable Trays, and Cable Penetrations (1) 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 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