Distance from the Bottom of a Slab

[jar546]

What code, if any dictates how close to the bottom of a structural slab, in this case, this is the second-floor conduit can be to the bottom of the slab which will act as the ceiling above?

How close is too close?

Who specifies the attachment of equipment from underneath to reduce the chance of penetrating the conduit and damaging the wires?

 

[jar546]

Hopefully, in this case all of the attachments from underneath are spec'd out so we don't end up damaging the wires.