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:
water at least to standpipes and hose connec- tions for manual firefighting in areas containing equipment required for safe plant shutdown in the event of a Safe Shutdown Earthquake. The piping system serving such hose stations should be analyzed for SSE loading and should be provided with supports to ensure system pressure integrity. The piping and valves for the portion of hose standpipe system affected by this functional require- ment should, as a minimum, satisfy ANSI B31.1, "Power Piping." The water supply for this condition may be obtained by manual operator actuation of valves in a connection to the hose standpipe header from a normal Seismic Category I water system such as the essential service water system. The cross connection should be (a) capable of providing flow to at least two hose stations (approx- imately 75 gpm per hose station) and (b) designed to the same standards as the Seismic Category I water system; it should not degrade the performance of the Seismic Category I water system. (5) The proper type of hose nozzle to be supplied to each area should be based on the fire hazard analysis. The usual combination spray/straight-stream nozzle should not be used in areas where the straight stream can cause unacceptable mechanical damage. Fixed fog nozzles should be provided at locations where high-voltage shock hazards exist. All hose nozzles should have shutoff capability. (Guidance on safe distances for water application to-live electrical equipment may be found in the "NFPA Fire Protection Handbook.") (6) Certain fires, such as those involving flammable liquids, respond well to foam suppression. Consideration should be given to use of mechanical low-expansion foam systems, high-expansion foam generators, or aqueous film-forming foam (AFFF) systems, including the AFFF deluge system. These systems should comply with the requirements of NFPA 11, NFPA 1lA, and NFPA l1B as applicable. d. Halon Suppression Systems Halon fire extinguishing systems should,