Not Part of the NFPA 13 Hanger Assembly
I get many technical questions regarding code and standard jurisdiction for the structural support bracket. The answer to these questions varies, but usually includes both the building code and NFPA 13, Standard for the Installation of Sprinkler Systems, for different reasons.
In defining the structural support bracket (SSB), we should note that it is commonly used to provide fire sprinkler system support in building systems which use a hybrid wood roof structure. The SSB provides an approved point of building structural attachment for hanger mounting that corresponds to the fire sprinkler routing locations for cross mains and bulk mains. The fire sprinkler contractor provides system pipe location and identifies specifics regarding its weight. When the SSB is provided, the fire sprinkler contractor is required to mount the fire sprinkler hangers to it.
NFPA 13’s jurisdiction for the SSB is limited to performance specification.
The bracket is designed for installed sprinkler hanger load at 1wt + 250 lbs. NFPA 13 considers the SSB as part of the structural roof assembly and not part of the fire sprinkler hanger assembly. Accordingly, the SSB is not a listed hanger component per NFPA 13. Further, the mounting of the SSB bracket to the building structure is beyond the purview of NFPA 13 or the fire sprinkler contractor.
The SSB is within the jurisdiction of the building code as a structural component. Thus, the fire sprinkler contractor has no direct input regarding SSB engineering or design. The structural engineer of record provides the SSB material specification, including its method of attachment to the structure. Then, the roof contractor provides and installs the SSB bracket corresponding to the geometry of the fire sprinkler system.
Occasionally, Authorities Having Jurisdiction (AHJs) request a position statement regarding “Alternate Methods and Means” per NFPA 13. This article should be used to alleviate that requirement.
ABOUT THE AUTHOR: Kraig Kirschner is a third-generation fire sprinkler contractor and a journeyman fitter. He is a principal member of NFPA 13 – Hanging and Bracing Technical Committee and serves on Standard Technical Panels of UL 203, UL 203A and FM 1950. Kirschner is a Life Member of the National Fire Protection Association (NFPA) and was named Person of the Year in 2009 Fire Protection Contractor magazine. He holds dozens of patents that enhance the installation and application of hangers and sway braces.