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Many listed hanger fasteners have their own weight limits. When I calculate the allowable hanger spacing for different size pipes, should I be using the Ultimate Pullout, UL Test Load, or FM Test Load?
Just looking at the Sammys for Wood Vertical (https://www.swfastener.com/pdf/ITW%20Sammy.pdf), for instance - some of the wood screws can have three different load values and I'm not entirely sure which I should be using to determine the appropriate hanger spacing for a sprinkler system. Thanks in advance. Posted anonymously for discussion. Discuss This | Submit Your Question | Subscribe
3 Comments
Dan Wilder
4/30/2020 08:21:13 am
For the same MFG, please look at the more current catalog, which on Page 14 shows the listings for both UL & FM in a maximum pipe size available. Typically, anything with fire sprinkler listings or approvals are shown with a maximum pipe size but you may need to reference this based on the UL listing or FM approval sheet if the MFG data sheet does not specify. ICC-ES sheets are also very helpful with exactly how items are to be installed and in what conditions.
Casey Milhorn
4/30/2020 10:19:58 am
I think you are asking what number to use when comparing to the weight of the water filled pipe x 4 + 250 lbs (Per NFPA 13). If that's the question, then go by the UL listing (if its a UL job), FM listing (if its a FM job), or your choice if the job doesn't have a specific listing agency in the specs. So for example, if your weight of your pipe + 250 lbs equals 350 lbs at a 10' spacing, and your UL listed test load is 360 lbs, then you are in good shape. Rarely have I ever seen an issue with the listed pullouts not being enough to space hangers to 12' or 15' per NFPA 13. But it is worth checking for when dealing with a new hanger attachment or larger pipe.
Mike
5/5/2020 10:30:47 am
In the appendix it states the 250# is a safety factor. Leave a Reply. |
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