Control Valve
“Per 17.1.2.9.6, the in-rack sprinkler demand shall not be required to be hydraulically balanced with the ceiling level sprinkler system. Does the in-rack system for this alternate protection scheme require a separate control valve or riser and supply piping? If not, can the in-rack system be tied into the ceiling level sprinkler system if it is hydraulically proven? Is the outside hose demand for this in-rack system 500 gpm?” We have reviewed NFPA 13, 2016 edition as the applicable standard. Our informal interpretation is noted below. There is little guidance regarding alternative protection and in-rack sprinkler systems. As such, default to 8.16.1.5 for in-rack sprinkler system control valves. Separate indicating control valves and drains shall be provided and arranged so that ceiling and in-rack sprinklers can be controlled independently per Section 8.15.1.5.1. Separate control valves are ideal since in-rack sprinklers are susceptible to damage due to their location. The separate control valves allow the ceiling system to remain in service while the in-rack sprinkler protection is being restored. Conversely, the in-rack system would remain operational when the ceiling system is out of service. There are two exceptions for this arrangement. Section 8.16.1.5.2 says that installation of 20 or fewer in-rack sprinklers supplied by any one ceiling sprinkler system shall not require a separate indicating control valve. This permits an in-rack sprinkler system to be supplied from the overhead system without a separate control valve. The other exception is 8.16.1.5.3 where separate indicating valves can to be arranged as sectional control valves supplied from the ceiling sprinkler system where in-rack sprinklers are required and the racks including the adjacent aisles occupy 8,000 sq. ft. or less of the area protected by the ceiling sprinklers. This applies where the in-rack system has more than 20 sprinklers but only occupies a portion of the area protected by the overhead system. This allows the in-rack system to be isolated without affecting the ceiling sprinkler system. The area is limited since impairment to the overhead system will also impair the in-rack system. Lastly, the 500-gpm hose stream allowance does not apply to in-rack sprinklers since it’s included with the ceiling sprinkler system. ========= 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/20170403/b8a197e6/attachment.htm>
