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Sway Bracing

To Whom it May Concern,

It seems that many people are having trouble with the earth quake sway bracing requirements of NFPA. In the old days, it was much easier, now there are many more rules. I will try to identify some of the problems that I see consistently. Obviously, this list is not inclusive. Also, just as obviously this list does not pertain to everyone.

  • The braces must be identified. Example: On the calculation page identify each brace by a name. “Lateral 1, etc.”. Then on the drawing the brace must be identified as “Lateral 1”. In this manner, the fitter and the field inspector will know exactly, which brace goes in which location.
  • The braces much attach to structural members. You cannot just randomly or equally space the braces. The structural members at the randomly or equally spaced location may not be capable of supporting a sway brace. Therefore, you must examine the structural members at each location and design the bracing accordingly. You may find additional bracing is required.
  • The calculation's sheet must show load rating for all components. I receive many calculations where the component load is indicated as zero. This is not acceptable. The whole idea of the calculations is to make sure the bracing can accept the design load. How can a component that is indicated as zero except any type of load? In addition, how did you verify that the load was acceptable?11/16/2010
  • Lateral bracing is not spaced at one specific distance. There are tables in NFPA that indicate the maximum distance between bracing based on the load and pipe size. Many of you are apparently not familiar with these tables. See Tables NFPA 13: 9.3.5.3.2 (a,b)
  • The length of the braces seems to be ignored. You cannot calculate a length of 3’-6” and then install a 7’-0” brace. The calculations will not be correct for the specific brace.
  • Through bolts are required for wood. See NFPA 13: 9.3.5.9.3
  • I have received several plans with machine bolts use to attach to wood. How does this work? Please, check your calculations thoroughly to avoid time delays and denials in the plan review process.
  • Branch line restraints are required. They are more than a hold down clip. See NFPA 13: 9.3.6 also see the spacing Table 9.3.6.4.
  • NFPA 13: 9.3.5.3.1* Lateral sway bracing shall be provided on all feed and cross mains regardless of size and all branch lines and other piping with a diameter of 2½ in. (65 mm) and larger. It seems many people are unfamiliar with this section. I have highlighted a few important phases.
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  • I will not accept bracing attached to the bottom of a wood chord joist, unless calculations are supplied by a Professional Engineer.

 

I hope this helps a little. Again it is not meant to be all inclusive. We all receive a ton of email daily. I would like to hear from you if you think this kind of email is helpful or a hindrance.

Thank you for your time.

 

 

Cordially,

Tim Frost, S.E.T.
Fire Sprinkler Plans Examiner

Fire Plans Examiner

Fire Inspector II
City of Boise

208-384-3781
tfrost@cityofboise.org