CW mechanical attachment below the slab - how it is thermally protected?

Hilti FE asking on behalf of my specifier....
My architect has a CW mechanical attachment on the face of the slab and it bends to attach underneath the slab as well.  They plan to use one of our Zero spandrel firestop systems.  If any of the mechanical attachment is below the floor slab, does it need to be protected with mineral wool?  If not, how can approx. 5" deep of mineral wool backing for the FS system be enough to protect the mechanical attachment of the curtain wall itself?