The hoistway shall be constructed and enclosed in accordance with the requirements of § 7.51 (relating to shaftway construction), except that when a building is of open construction throughout, and the elevator does not travel through fireproof floors, grille, or latticework, an enclosure 6 feet high shall be provided around the shaftway at each floor. An enclosure of full height shall be provided on the open side or sides of the car and on other sides where hazards exist, such as stairways. The grille or or latticework shall conform to § 7.51.
34 Pa. Code § 7.181
This section cited in 34 Pa. Code § 7.191 (relating to limitations).