Pre-requisite Check:
Make sure that the architect gives you floor space instead of pushing you into the ceiling. The only one that can enforce such a thing is the owner or his maintenance guy. The poor engineers have no weight in decision making.
For most engineers out there: Please make sure your VAV boxes, dampers, valves etc, are accessible (i.e no higher than 11 feet above finished floor), and of course no AHU/FCU in ceiling space. As for Mechanical rooms, make sure you have a pathway to remove every single piece of equipment from the space.
It is criminal to give a brand new facility to an owner who spent money hiring a bunch of "Experts" only to be handed a non-accessible and non-serviceable Mechanical equipment.
You need to take a stand against the architect when they shove you into the ceiling space, you owe it to the wage payer.
Good on y'all