// CODE SNIPPET
9.3.5* Sway Bracing
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The system piping shall be braced to resist both lateral and longitudinal horizontal seismic loads and to prevent vertical motion resulting from seismic loads.
The structural components to which bracing is attached shall be determined to be capable of resisting the added applied seismic loads.
When a shared support structure is used to support gravity and seismic loads, the structure shall be designed to support these loads for all pipe and distribution systems on the structure using either 184.108.40.206.3 or 220.127.116.11.4 with an importance factor, Ip, of 1.5 being applied to all of the distribution systems.
If a shared support structure is used to support sprinkler pipe and other distribution systems per 18.104.22.168.1 and that structure does not provide seismic resistance as required in 22.214.171.124.4, the following shall be met:
- The sprinkler pipe shall be braced using the method in 126.96.36.199 with the zone of influence including the water-filled sprinkler pipe and all other distribution systems that are not independently equipped with seismic protection and attached to the shared support structure.
- The sprinkler sway bracing attachment shall be connected to the same building or structure as the shared support structure.
Sway bracing assemblies shall be listed for a maximum load rating, unless the requirements of 188.8.131.52.2 are met.
Bracing fittings and connections used with those specific materials shall be listed.
The listed load rating shall be reduced as shown in Table 184.108.40.206.3 to determine the allowable load for installations where the brace is less than 90 degrees from vertical.
Table 220.127.116.11.3 Listed Horizontal Load Adjustment
|Brace Angle Degrees from Vertical||Allowable Horizontal Load|
|30 to 44||Listed load rating divided by 2.000|
|45 to 59||Listed load rating divided by 1.414|
|60 to 89||Listed load rating divided by 1.155|
|90||Listed load rating|
Maximum allowable horizontal loads shall be determined by testing at angles of 30, 45, 60, and 90 degrees from vertical and confirmed to be equal to or greater than those calculated using 18.104.22.168.3.
Nonferrous components that have been proven by fire tests to be adequate for the hazard application, that are listed for this purpose, and that are in compliance with the other requirements of this section shall be acceptable.
Tension-only bracing systems shall be permitted for use where listed for this service and where installed in accordance with their listing limitations, including installation instructions.
For all braces, whether or not listed, the maximum allowable load shall be based on the weakest component of the brace with safety factors.