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:
ke and exhaust ventilation dampers should be controlled, in accordance with appropriate standards, to maintain the necessary gas concentration (see NFPA 12, “Standard on Carbon Dioxide Extinguishing Systems” (Ref. 82); NFPA 12A, “Standard on Halon 1301 Fire Extinguishing Systems” (Ref. 83); and NFPA 2001, “Standard for Clean Agent Fire Extinguishing Systems” (Ref. 84). Also, see Regulatory Position 4.1.4.4 of this guide). The adequacy of gaseous suppression systems and protected-area boundary seals to contain the gas suppressant should be tested, as specified in the applicable NFPA standards. Manually actuated gaseous suppression systems should not be used as the primary suppression system for protecting SSCs important to safety. Manually actuated gaseous systems are acceptable as a backup to automatic water-based fire suppression systems. 3.3.2.1 Carbon Dioxide Systems Carbon dioxide (CO2) extinguishing systems should comply with the requirements in NFPA 12. Where automatic CO2 systems are used, they should be equipped with a predischarge alarm system and a discharge delay to permit personnel egress. Provisions for locally disarming automatic CO2 systems should be key locked and under strict administrative control. Automatic CO2 extinguishing systems should not be disarmed unless controls, as described in Regulatory Position 2.4 of this guide, are provided. DG-1359, Page 51 In addition to the guidelines of NFPA 12, licensees should ensure preventive maintenance and testing of the systems, including verifying agent quantity of high-pressure CO2 cylinders. 3.3.2.2 Halon Halon fire extinguishing systems should comply with the requirements of NFPA 12A. When automatic Halon systems are used, they should be equipped with a pre-discharge alarm and a discharge delay to permit personnel to exit. Provisions for locally disarming automatic Halon systems should be key locked and under strict administrative control. Automatic Halon extinguishing systems should not