Section R. 400.18649 - Stairways and other vertical openingsRule 649.
(1) In buildings of fire-resistant construction, an interior stairway shall be enclosed with material that has a fire-resistance rating of not less than 1 hour. In buildings of wood joist construction an interior stairway shall be enclosed with material having 1/2-hour-fire-resistance rating. One quarter-inch wired glass in a steel frame meets the 1/2-hour requirement.(2) An elevator or dumbwaiter shaft shall be completely enclosed by noncombustible materials that have a fire-resistance rating of not less than 1 hour. An opening shall not be allowed through the side wall enclosures for ventilating or other purposes. A door that services an elevator or dumbwaiter shall be of solid construction, be reasonably smoketight when closed, and shall be constructed to resist fire for 1 hour. Exception: A door in an elevator may have wired glass that is not more than 6 square feet.
Mich. Admin. Code R. 400.18649