We have a tree, wet system, we are using Schedule 7 for the mains and branch lines.
We are trying to design the seismic bracing, and the main is only strong enough for one side of branch lines, not the opposite side too. Should we use stronger pipe, or install more laterals? Is there a way to brace the branch lines to take the weight off the mains? Thanks in advance. Sent in anonymously for discussion. Click Title to View | Submit Your Question | Subscribe
6 Comments
JI
12/27/2023 08:32:08 am
When I have this problem, I tend to lower the spacing for laterals to 30 ft which allows for a greater zone of influence to be used as per the charts in NFPA 13, and also lowers the footage of pipe required in the brace calculation.
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Casey Milhorn
12/27/2023 09:57:28 am
I agree with the first comment. I would probably do a quick and dirty cost analysis on the two scenarios. Also check your hydraulic calculations to make sure the change to sch. 10 doesn't hamstring you and cause larger main/line sizing.
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Dan Wilder
12/27/2023 10:11:44 am
My designs always added more main bracing to avoid branch line bracing at all costs. You would need to add longitudinal bracing to the BL’s to remove weight from the main.
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Pete D.
12/27/2023 11:27:58 am
What size is the main? Note that the schedule 5 table for maximum horizontal loading stops at 4" diameter. In the notes it states, larger diameter can be used when justified by engineering analysis.
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sean
12/31/2023 06:36:07 pm
I think I too would lean towards sch 5.
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Michael Christensen
1/18/2024 11:53:39 am
All of the manufactures that I am aware of (such as Eddy-Flow or Mega-Flow) publish their own tables that have the information. When I have used Sch 7 piping I reference the table from the manufacture when doing these calculations.
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