Stair Rail Specifications

Stair rails can be constructed of wood or metal.Thomas Northcut/Photodisc/Getty Images

The Occupational Safety & Health Administration (OSHA) regulates the guarding of floor and wall openings and holes, according to the United States Department of Labor website. Regulations in accordance with Section 1910.23(e) deal with railing specifications.

Railing Requirements

Standard railing requirements for stairways consists of posts, top and intermediate rails, according to the OSHA website. Measurement requirements specify a vertical height of 42 inches from the ramp, runway, platform or floor to the upper surface of the top rail. Vertical height of stair railing measurements equal not more than 34 inches or less than 30 inches from the top rail surface to the forward edge of the tread surface in line with the riser face. Check to be sure the entire length of the top rail is smooth with no projections. Position the intermediate rail approximately halfway between the top rail and the bottom surface. Allow for overhangs of railings only when a projection hazard is not discernible. If constructed of wood, use at least 2 by 4-inch stock for the top and intermediate rails in addition to the posts.

Standard stair railings are required on a flight of stairs possessing four or more risers, according to the Safety Is Us website. On stairways that are enclosed on both sides and measure less than 44 inches wide, at least one handrail is required. For open stairways measuring less than 44 inches, handrails are required on both sides. Stairways wider than 44 inches but less than 88 inches require handrails on both sides. Stairways measuring 88 inches wide require handrails on both sides, in addition to an intermediate handrail placed approximately in the middle of the staircase. The interior handrail of a winding staircase extends in from the center of the spiral to a point where the stair treads below it are at least 6 inches wide. This prevents people from walking on the portion of the tread that is narrower than 6 inches.

Placement of pipe railings on stairways is no different than placement of their wood counterparts. Required measurements for pipe railings consist of 1 and 1/2 inches in diameter for the top and intermediate rails. Structural steel railings on stairways, in regard to the top and intermediate rails, in addition to the posts, measures 2 inches by 2 inches by 3/8 of an inch angles. Use materials and construction techniques that produce a railing capable of supporting 200 pounds of weight applied in any direction on the top rail.