American Fire Sprinkler Association 12750 Merit Dr., Suite 350 * Dallas TX 75251
Ph:(214) 349-5965 Fax:(214) 276-0908 ------------------------ TECHNICAL UPDATE APRIL 1, 2009 ------------------------ The engineer has indicated a 4 in. PRV at each floor of a combined system where the standpipes are manual wet. The PRV is after the floor control valve. At least one system is Ordinary Group II and is requiring 380 gpm flowing through the PRV. The floor drain is 2 in. and the vertical drain riser is 2 in. (non-conforming). How do you know if the drain size is adequate to meet 8.16.2.4.5? We have reviewed NFPA 13, 2007 Edition as the applicable standard. Our informal interpretation is that the engineer of record should provide an answer. NFPA 13 does not provide criteria for drains with a high flow discharge and advocates to have the drains discharge directly to the outside. The floor drains or mop sinks are usually inadequate to handle flows from fire sprinkler systems for main drain tests and for flow testing of PRVs. Floor drains or mop sinks are adequate for smaller auxiliary drains when the system is being drained. The size of drains for higher flow rates can be found within some of the manufacturer?s data sheets. For example a Zurn Siphonic type drain data sheet shows that it can handle flow rates of 149 gpm with a 2 in. size drain, 380 gpm with a 3 in. and 704 gpm using 4 in. size drain. Additionally, the 2007 Edition of NFPA 14 Section 7.11.1 does specify a drain size and it states, ╥A permanently installed 3 in. (76 mm) drain riser shall be provided adjacent to each standpipe equipped with pressure-regulating devices to facilitate tests of each device.╙ Since there is no guidance in NFPA 13, the engineer of record should be consulted. ----------------- Technical Update is prepared by the Technical Services Dept. of the AFSA: Vice President of Engineering and Technical Services Roland Huggins, a PE registered in fire protection engineering; Phill Brown, a NICET IV certified automatic sprinkler technician and NFPA Certified Fire Protection Specialist (CFPS) and Tom Wellen, a degreed fire protection engineering technologist. 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 ⌐ 2009, American Fire Sprinkler Association. All Rights Reserved -------------------------- If you╒d rather not receive future faxes from AFSA, fax your removal request to Amy Sweeney at Efax (214) 242-3155 or call toll free (888) 839-4830 or send e-mail request @ [email protected]. Please include your company name and the specific fax numbers(s) at which you do not wish to receive faxes from us. Our failure to comply with your request may be unlawful. _______________________________________________ Sprinklernotes mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklernotes
