American Fire Sprinkler Association 12750 Merit Dr., Suite 350 * Dallas TX 75251 Ph: (214) 349-5965 Fax: (214) 276-0908
----------------- TECHNICAL UPDATE JANUARY 20, 2010 ----------------- Does the requirement for five times the weight of the water filled pipe plus 250 pounds apply to the ability of the structure to which the listed hanger assembly is supported from as a point load? We have reviewed NFPA 13, 2007 Edition as the applicable standard. Our informal interpretation is that the structure does not have to support five times the weight of the water-filled pipe plus 250 pounds. This is supported by Section 9.2.1.3.1 the sprinkler piping shall be substantially supported from the building structure, which must support the added load of the water-filled pipe plus a minimum of 250 pounds applied at the point of hanging. There are requirements for hanger components as part of their listings to be designed to handle higher loads than what is indicated by the manufacturer data sheets (if the load ratings are published). These are known as safety factors. We see this in Section 9.1.1.2 that if the hanger is engineered, the hangers shall be designed to support five times the weight of the water-filled pipe plus 250 pounds at each point of piping support. So, an engineered support has safety factor of five. Note that there is no mention in Chapter 9 that the structure at the point of attachment has to support five times the weight of the water-filled pipe. That only applies to hanger components. When these requirements were first written, the idea was and still is that everything else will fail before the fire protection system fails. The 250-pound load referenced above represents the extra stress imposed by system installation, future construction activities, and physical impact from equipment. Thus, hangers for sprinklers will continue to be designed for larger loads than other system's hangers since sprinklers provide life safety and property protection. ----------------- 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 © 2010, 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://fireball.firesprinkler.org/mailman/listinfo/sprinklernotes
