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:
more than 30 percent. If a fire barrier test specimen without cables does not meet the average or maximum single point temperature criteria, the internal raceway temperature profile as measured by the instrumented bare copper conductors during the fire exposure can be used to assess cable functionality through air oven tests of plant-specific cable types and construction, as discussed below. B-2. Hose Stream Tests NFPA 251 and ASTM E119 allow flexibility in hose stream testing. The standards allow the hose stream test to be performed on a duplicate test specimen subjected to a fire endurance test for a period equal to one-half of that indicated as the fire-resistance rating, but not for more than 1 hour (e.g., 30-minute fire exposure to qualify a 1-hour fire-rated barrier). For safe-shutdown-related fire barrier systems and duplicate electrical cable tray or raceway and component fire barrier test specimens that have been exposed to the test fire exposure of one-half duration, the staff finds the hose stream application specified by NFPA 251 to be acceptable. NFPA 251 requires the stream of water to be delivered through a 64-mm (2.5-in.) hose discharging through a standard 38-mm (1.5-in.) playpipe nozzle onto the test specimen after the fire exposure test. The stream is applied with the nozzle orifice positioned 6.1 meters (m) (20 feet (ft)) from the center of the test specimen at a pressure of 207 kilopascals (kPa) (30 pounds per square inch (psi)). The application of the stream is to all exposed parts of the specimen for a duration of at least 1 minute for a 1-hour barrier and 2.5 minutes for a 3-hour barrier. As an alternative to electrical raceway fire barrier test specimens, the hose stream test can be performed immediately after the completion of the full fire endurance test period. If this method is used to satisfy the hose stream test criteria, any one of the following hose stream applications is acceptable: a. The stream applied at random to all exposed