Section R. 400.18634 - Stairways and other vertical openingsRule 634.
(1) An interior stairway shall be enclosed with material that has a fire resistance rating of not less than 1 hour. Other vertical openings through floors and ceilings, such as spaces around pipes, conduits, and ducts, shall be firestopped with noncombustible material.(2) An elevator or dumbwaiter shaft shall be completely enclosed by noncombustible materials with a fire-resistant rating of not less than 1 hour. Openings shall not be permitted through the sidewall enclosures for ventilation or any other purpose. A door and frame that services an elevator or dumbwaiter shall be approved fire door construction and shall be hung so as to be reasonably smoketight when the door is closed. A lintel or panels above the door shall be constructed to resist fire for 1 hour. Where necessary, the door shall have wired glass that is 1/4-inch thick and the glass shall not be more than 100 square inches.(3) There shall be no room doors or openings into stairways other than corridor access doors, except where a floor consists of a single open area, such as a large open ward floor.Mich. Admin. Code R. 400.18634