We have a 6-inch Schedule 10 main being hung with a trapeze hanger. The span on the hanger is 6-ft.
We're using a 2-1/2 inch Schedule 40 pipe as the trapeze.
Does the 2-1/2 inch hanger rings and rods with beam clamps need to use 1/2-inch diameter rod, since it is supporting 6-inch pipe, or can it use 3/8-inch hanger rings and rods?
NFPA 13 2016 Section 22.214.171.124.5 states "all components of each hanger assembly that attach to a trapeze member shall conform to 126.96.36.199 and be sized to support the suspended sprinkler pipe." Table 188.8.131.52 shows pipe sizes up to 4-inch require a minimum 3/8-inch rod and 6-inch requires a minimum of 1/2-inch rod.
Thanks in advance.
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6/10/2022 06:39:21 am
Consider a heavy duty band hanger for trapeze, then you use the diameter of your trapeze pipe... but these are pricier:
6/10/2022 08:13:09 am
These heavy duty hangers are great, and frankly you can't properly install a trapeze hanger assembly without them.
6/10/2022 10:03:51 am
This is exactly how you make this type of trapeze hanger work.
6/10/2022 08:06:44 am
You need to provide support for the weight of the waterfilled pipe, in this case the 6" which will have to be 1/2" rod per NFPA 13 chapter 9 requirements.
6/10/2022 08:09:14 am
All hardware shall be 1/2 diameter. There are specific hangers that have the larger sized knurl for pipe sizes 4” and smaller , just for trapeze assemblies. Yes, they are pricey but they are the easiest way to stay compliant.
6/10/2022 08:12:16 am
All the rods being used are to be sized based on the pipe being supported. So you will need to support both the trapeze member and the 6" schedule 10 main with 1/2" rod.
6/10/2022 08:47:40 am
You can also use clevis style rings on the trapeze which are cheaper than the heavy duty rings. 1/2" rod and beam clamps can be used with them throughout the application.
6/10/2022 09:04:47 am
Don't forget to check out the Section Modulus in NFPA 13 and Trapeze Hangers to make sure you are using the correct pipe size and schedule.
6/10/2022 10:01:27 am
NFPA #13 says ALL components of each hanger assembly that attach to a trapeze member shall be sized to support the suspended sprinkler pipe.
6/10/2022 10:04:21 am
In other words, all compomnents must be sized for the 6" pipe.
6/10/2022 10:11:55 am
The NFPA #13 handbook used a similar example to explain that if the load were closer to one end of the trapeze, the load would be concentrated on one hanger and may not be able to support the load and changed the rules in 2007 to require all components to be sized to support the sprinkler main, though it is the more conservative approach. This does not preclude an angineer designing a trapeze with lesser components under the performance-based design option.
6/11/2022 12:23:47 pm
A few more tidbits of information to add to the conversation. Per NFPA 13-2019 section 17.1.2 (1) hangers are to support five times the water filled weight of the pipe plus 250 lb. (person) at each point of piping support.
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