Floor Penetration Supports

[CommonSpark]

I have taken over an old job from an engineer who left the firm & received an RFI about a conduit support detail. The detail calls out the conduit to be strapped to unistrut which is attached to the bottom side of the slab with 3/8" HILTI KB-TZ2. I've been digging through California Electric Code & cannot find a reason this detail is there. I've looked through CEC (california electric code) 300.19(A) & CEC 300.19(C)(2) for verticle supports & only see a requirements for spacing & methods of support.

 

[infinity]

Why the bottom side of the slab?

 

[Greentagger]

Maybe a duct bank detail to allow encasement?

 

[CommonSpark]

I coordinated with the SEOR on the project. The bracing was a requirement for a UL fire stopping detail that was being used. The conduit was penetrating from a basement up to a first floor.