Roof Access is critical in commercial buildings especially if there is mechanical equipment located on the roof (flat roof). The traditional 30"x36" roof hatch and vertical ladder are inadequate. Maintenance of both the roof and the equipment located there require easy and safe access for inspection and bringing tools and filters onto the roof. The taller the building the more necessary this roof access becomes.

A Ship's Ladder and Roof Hatch are the least expensive way to meet this need for maintenance access.

Very High Ladders require require special consideration of OSHA regulations. A cage around the ladder may be required if the rise is more than 20'. 

If the goal of a folding wall is both visual AND sound separation, pay special attention to wall rating, seals and provide a sound barrier above the ceiling. Creating the barrier with drywall, while possible, rarely works as intended. Fixing a sound problem later is often imperfect because it is just too complicated.

Lead sheet is the ideal material for blocking sound because it is dense and flexible for an airtight fit around penetrations and the perimeter of the ceiling plenum. Lead is not a good idea any more for environmental reasons. The material we have used as a replacement is:
SoundBlocker1™  - Reinforced Flexible Sound Barrier
See http://www.gretchken.com/

Avoid duct penetrations and use dampening in ducts that connect to spaces you want to isolate.

Be sure to inspect the work before subcontractor leaves. Test by clapping or loud music to see if it is satisfactory.