Section 708 establishes requirements for smoke barriers in hospitals, nursing homes, and other institutional occupancies where residents cannot evacuate quickly. Smoke barriers are rated assemblies designed specifically to resist smoke passage and are typically 1-hour fire-resistance rated. A smoke barrier must divide each story of hospitals and nursing homes into at least two spaces, permitting horizontal evacuation. The barrier must extend from the floor to the deck or roof above, through all concealed spaces, with all openings protected by smoke-sealed doors. Refuge areas on the non-fire side of the barrier must provide temporary safety for occupants during evacuation. The refuge area must have sufficient floor area to accommodate all occupants with at least 5 square feet per patient or occupant. Temporary refuge areas during evacuation may include unaffected smoke barrier compartments. Stairwell walls in hospitals and nursing homes that have direct access to occupied spaces must have doors opening into a vestibule or lobby creating additional separation. Mechanical systems must be designed to prevent smoke migration between compartments. Ductwork crossing smoke barriers must include smoke dampers that close automatically upon smoke detection. Return air systems must filter air before recycling, or exhaust all air. The smoke barrier location must facilitate evacuation with one refuge area closest to the fire area, allowing horizontal movement of patients to the adjacent compartment.