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:
to the cable system. Cables should be designed to allow wetting down with water supplied by the fire suppression system without electrical faulting. Open-head deluge and open directional spray systems should be zoned so that a single failure will not deprive the entire area of automatic fire suppression capability. The use of foam is acceptable so long as it is a type that can be delivered by a sprinkler or deluge system. Alternative gas systems (Halon, clean agent, or CO2) may be used for primary fire suppression if they are backed up by an installed water spray system and hose stations and portable extinguishers immediately outside the room. The access requirements stated above should also be met. DG-1359, Page 95 Floor drains should be provided to remove firefighting water. When gas systems are installed, drains should have adequate seals, or the gas extinguishing systems should be sized to compensate for losses through the drains. The ventilation system for each cable spreading room should be designed to isolate the area upon actuation of any gas extinguishing system in the area. Separate, manually actuated smoke venting that is operable from outside the room should be considered for the cable spreading room. 6.1.4 Plant Computer Rooms Rooms for computers performing functions important to safety that are not part of the control room complex should be separated from other areas of the plant by barriers having a minimum fire-resistance rating of 3 hours and should be protected by automatic detection and fixed automatic suppression. Computers that are part of the control room complex but are not located in the control room should be separated and protected as described in Regulatory Position 6.1.2 for peripheral rooms. Computer cabinets located in the control room should be protected as other control room equipment and cable runs in the room. Nonsafety-related computers outside the control room complex should be separated from plant areas important to safety by