How do you all do it? I envisage ducts "hanging" from brackets nailed or screwed into the above floor slab. Suspended ceiling then goes in after all services done.

 

Is this correct? I suspect this would result in a lot of fixings... We have two precast floors to fix to. (Hence thread about nail guns)

 

Any other methods? Worth fixing batons first?

Drill and plug or drill and use expanding anchors for fixing into ceilings.

Ducting can/will vibrate as air flows through it and the last thing you want is nails working loose and coming free. Plus precast slabs can be incredible difficult to fire nails into.