Vertical piping seismic restraint to NZS4219

[moyseh]

Hi,

I am working as a seismic design engineer and designing bracing for some vertical pipes.
I was wondering whether the floor slab provides any form of restraint for the vertical pipes or if they need to be restrained specifically.

 

[rowingengineer]

Unsure of the exact situation but I assume you taking about vertical pipe penetrating thru a concrete slab. Normally these do have a collar that connects the pipe to the slab, these collars can be designed with some give in mind or as hard supports. The collars are often for fire spread requirements, but a quick assessment of the collar on your project should answer the question.

 

[LuK13]

In a previous life I worked as a sprinkler design tech and part of my job included seismic bracing design for the sprinkler pipes.

Disclaimer: I have no experience with NZS4219, and the information I provide below is based on fading knowledge of older editions of NFPA standards and FM Global data sheets. Your mileage may vary. Be sure to review the applicable design standards for specifics on your job.

The fire protection risers would pass through floor slabs via sleeves. The annular space of the sleeves would be filled with various materials to me the fire rating of the floor. You can check out Hilti's standard firestopping details for some ideas.

The sleeve just has to be bigger than the riser to get the riser through the slab. In theory you could have a very oversized sleeve with a lot of annular space. In order to take credit for the slab as a four way brace, you had to limit the annular space to a code prescribed maximum. There were "gotcha" situations where if the riser was not installed center of the sleeve you could violate the maximum annular space. If the riser was shoved tight against the sleeve in the -X direction, you would have too much travel in the +X direction before the riser engaged the slab. Not that the EOR or AHJ was ever looking that closely at things on any job I was on, but it is good to be aware of it incase you get someone that does.

So in summary maybe. Review your applicable codes and maybe try posting in a more appropriate forum based on the service. You will probably get better answers from the people designing the pipes than the people designing the slabs.