Minimum Remote Area
“I have an extra hazard (Group 2) area enclosed with walls and ceilings that measures about 1,250 sq. ft. Do I have to pick the remainder square feet to reach 2,500 sq. ft.?” We have reviewed NFPA 13, 2010 edition that you indicated as the applicable standard. Our informal interpretation is that there are two possible design approaches for this application. The room design method per 11.2.3.3 would be beneficial for this application due to the smaller room size. The room is required to be enclosed with walls or partitions having a fire-resistance rating equal to the water supply duration indicated in Table 11.2.3.1.2. This table indicates 90 or 120 minutes. The density/area method can be used for other occupancy areas outside of the extra hazard area. If the walls or partitions do not have the minimum fire resistance rating, the density/area method would be applicable where the minimum 2,500 sq. ft. remote area has to be applied. The remote area would be extended beyond the walls of the extra hazard room. The minimum density 0.40 gpm/sq. ft. is applied to the 1,250 sq. ft. area. The ordinary hazard or light hazard occupancy, for example, would be applied for the remaining 1,250 sq. ft. area. Since there is a barrier per 11.1.2, the sprinkler protection for the more demanding design basis does not have to extend 15 ft beyond the perimeter. Thus, the remote area would have two different densities applied for the one remote area. The annex A.11.1.2 says that when the small higher hazard area is larger than the required minimum area dictated by the surrounding occupancy, even when separated by partitions capable of stopping heat, the size of the operating area is determined by the higher hazard storage. ========= Technical Update is prepared by the Technical Services Dept. of the AFSA: Roland Huggins, a PE registered in fire protection engineering, Vice President of Engineering and Technical Services; and Tom Wellen, a PE registered in fire protection engineering and Tom Noble E.T., a Technical Programs Specialist. This is provided with the understanding that the AFSA assumes no liability for this opinion or actions taken on it and they are not to be considered the official position of the NFPA or its technical committees. Copyright 2017, American Fire Sprinkler Association. All Rights Reserved. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.firesprinkler.org/private.cgi/sprinklernotes-firesprinkler.org/attachments/20170508/00337306/attachment.htm>
