R 408.42155 Specifications for stair rail.

Rule 2155. (1) A stair railing shall consist of a stair rail, a vertical support, and an intermediate rail or its equivalent to prevent an employee from falling through the opening between the stair rail and the stairs. The stair rail shall parallel the slope of the stairway. (2) A stair rail shall be smooth, made of 2- by 4-inch nominal-sized lumber, and constructed in a manner to withstand a side thrust of not less than 200 pounds. The height of a stair rail shall be as follows: (a) A stair rail that is installed after March 15, 1991, shall be not less than 36 inches (91.5 cm) from the upper surface of the stair rail system to the surface of the tread and in line with the face of the riser at the forward edge of the tread. (b) A stair rail that is installed before March 15, 1991, shall be not less than 30 inches (76 cm) nor more than 34 inches (86 cm) from the upper surface of the stair rail system to the surface of the tread and in line with the face of the riser at the forward edge of the tread. (3) The vertical post shall be constructed of not less than 2- by 4-inch nominal-sized lumber and shall be spaced not more than 6 feet (1.8 m) apart. (4) An intermediate rail or midrail shall be constructed of not less than 1- by 6-inch or 2- by 4-inch nominal-sized lumber and shall be installed midway between the stair rail and the treads. (5) Screens, mesh, intermediate vertical members, or equivalent intermediate structural members shall be provided between the top rail of the stair rail system and the stairway steps. (6) Screens or mesh, when used, shall extend from the top rail to the stairway step and along the entire opening between the top rail supports. (7) When intermediate vertical members, such as balusters, are used between posts, they shall be not more than 19 inches (48 cm) apart. (8) Other structural members, when used, shall be installed such that there are no openings in the stair rail system that are more than 19 inches (48 cm) wide. (9) A stair rail shall not have protruding nails or rough or sharp corners and shall not constitute a projection hazard. (10) Other material may be used if the stair railing meets the 200-pound side thrust requirement. (11) A stairway that has 4 or more risers or rises more than 30 inches (76 cm), whichever is less, shall be equipped with at least 1 handrail and at least 1 stair rail system along each unprotected side or edge. When the top edge of a stair rail system also serves as a handrail, R 408.42156(3) applies. (12) Winding and spiral stairways shall be equipped with a handrail that is sufficiently offset to prevent walking on those portions of the stairways where the tread width is less than 6 inches (15 cm).