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----------------- TECHNICAL UPDATE FEBRUARY 3, 2010 ----------------- “What is the correct all thread rod and hanger orientation when installing pipe on a pitched roof?” We have reviewed the 2002 and 2007 Editions of NFPA 13 as the applicable standards. Our informal interpretation is that the rod should be installed perpendicular to the pipe. The 2002 Handbook is misleading under Section 9.1.2.5 and installing an all thread rod perpendicular to the pipe is the industry norm and complies fully with NFPA 13. The 2002 Handbook wording “the rod must be in a true vertical position once it is connected” was removed and replaced with “the rod must be axially loaded once it is connected”. The 2007 Edition further addressed this issue with Section 9.1.2.3 that states, “Hanger rods shall be installed so that lateral gravity loads are not induced on the rods.” The annex shows Figure A.9.1.2.3 shows a sloped ceiling and that the hanger rods and rings are perpendicular to the pipe. The figure also shows an additional hanger is provided as one method at the cross main to reduce the non-axial loads on the hanger rods. This was modified during the A2009 Report on Proposals in 13-242 Log #145 with a committee action of Accept in Principle. This section will state in the 2010 Edition, “Where the pitch of the branch line is 6 in 12 or greater, a reduction in the lateral loading on branch line hanger rods shall be done by one of the following: (1)* a second hanger shall be installed in addition to the required main hangers, (2) lateral sway brace assemblies on the mains, (3) branch line hangers utilizing an articulating structural attachment, (4) equivalent means providing support to the branch line hanger rods.” Thus the hanger rods do not have to be installed in a true vertical position. ----------------- 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
