American Fire Sprinkler Association 12750 Merit Dr., Suite 350 * Dallas TX 75251 Ph: (214) 349-5965 Fax: (214) 276-0908
_____________________ TECHNICAL UPDATE AUGUST 20, 2009 _____________________ “When a pump is employed in conjunction with a water storage tank utilized as a secondary water source in seismic applications, how is the pump sized?” We have reviewed IBC, 2006 Edition and NFPA 13, 2007 Edition that you indicated as the applicable standard. Our informal interpretation is the fire pump is sized based on both water sources. For higher seismic design categories, IBC 903.3.5.2 requires a secondary on-site water supply equal to the hydraulic calculated sprinkler demand, including the hose stream requirement. As identified in NFPA 13:23.1.2 – “Water supplies shall be capable of providing the required flow and pressure….” Thus, the supply includes the pump and it must be capable of meeting the system demand whether the water is from the street or an on-site tank. The impact is that the pump must be sized for both available pressures. Typically, the street provides a higher-pressure contribution so it must be applied when evaluating the maximum churn pressure to ensure the system pressure rating is not exceeded. The contribution from the tank (assuming it is near ground level and does not exceed the pressure provided by the street supply) would be a lower pressure contribution and would be used to determine the minimum pump size in order to meet the sprinkler demand. ----------------- 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
