Pipe Bracing for Tall Building Sway

Question

Pipe Bracing for Tall Building Sway

NickDePinhoPE (Mechanical)

(OP)

27 Sep 24 13:31

Hello I am a PE with 6 years of experience mainly focusing on mechanical pipe supports for skyscrapers in NYC.

We have two senior engineers at my company who have differing views on the need for bracing on top of the building. Think 1000' tall skyscraper.
I am struggling to find in the codes if I have to design lateral or seismic bracing for the piping towards the top of these buildings.

I have read MSS-SP 58, MSS-SP 127, and the NYC building codes.
As far as I can tell based on MSS-SP 127 any pipe subject to wind load needs some type of bracing. In general we put seismic supports on piping involved in life safety but for HW,PCW, CHW piping we do not include any type of bracing.

Just curious if anyone can point me to a specific code that covers building sway for mechanical pipe supports.

Thanks!

RVAmeche (Mechanical) · Answer 1 · 2024-09-27 19:20:35

I don't work in skyscrapers but NFPA 54 calls out supports to prevent/damp vibrations for gas piping. I know the commercial building world is very different from heavy industry, but I would expect some straps or something to minimize movement during wind/seismic events at a minimum, if not snubbers.

While it's not a life safety item it seems prudent to minimize damage from design loads (such as seismic acceleration) for the headers.

1503-44 (Petroleum) · Answer 2 · 2024-09-27 21:28:18

The pipe needs to sway with the building. Bracing it may turn the pipe-brace structure into a rigid truss with less flexibility than the building.

Lots of ways to skin that cat. Can you show us what your proposed brace scheme looks like?

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

LittleInch (Petroleum) · Answer 3 · 2024-09-28 09:43:41

Why does everything need a code to tell you what you can and can't do??

This goes into the realms of Good Engineering Practice and the general sections of any piping design code which is do whatever is required to prevent failure of your pipe.

Code writers can't be expected to know everything and consider every set of circumstances and given the very few numbers of 1000ft high buildings this is one of them.

Read the intro and general sections at the start of your piping code if you need some sort of crutch for what is to me a simple must do.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

pmover (Mechanical) · Answer 4 · 2024-09-28 14:27:39

agree w/ LI.

you won't find a code.

consider this reference as a guide: https://wbdg.org/FFC/DOD/UFGS/UFGS%2023%2005%2048....

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Pipe Bracing for Tall Building Sway