The Occupational Safety and Health Administration (OSHA) is overseen by the Department of Labor and applies to areas not open to the public.

Railing requirements for OSHA are covered in Section 1910.29: Fall Protection Systems and Falling Object Protection — Criteria and Practices. Be aware that this section was updated in January 2017.

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OSHA’s Section 1910.29 refers to both handrails, guard rails, and handrail systems.

Handrail System

A stair with four or more risers requires a handrail.

Handrails must be between 36 inches and 38 inches (if built prior to January 2017, the height limitation is between 30 inches and 38 inches) as measured from the leading edge of the stair tread  — the nosing –  to the top surface of the handrail.

A finger clearance of 2-1/4” is required between the handrail and any other objects. While there is no dimensional limitation for handrail size, OSHA notes that handrail has the shape and dimension necessary so that employees can grasp the handrail firmly.

The handrail must be smooth surfaced to protect employees from injury and prevent catching or snagging of clothing. Additionally, the ends of handrail should not present any projection hazards.

If there is a drop of more than 48 inches, a guard rail would also be required. The minimum height of that guard rail is 42 inches.

The opening in a stair rail should be no larger than 19 inches.

Guardrail

OSHA is the only organization that uses the term guardrail. Generally, a guardrail is what’ is found on the side of a road to keep cars from going off the shoulder. In the built environment we tend to refer to a guard since it does not necessarily need to be assembled from rails – it could be a solid wall. However, in OSHA applications, the elements are most likely horizontal rails. So, the term is appropriate.

A guardrail is required once there is a 48-inch drop. As opposed to the requirements of handrail system, a guardrail must be 42 inches in height – plus or minus 3 inches above the walking surface. This was a construction allowance introduced so that the guard would  meet the requirement  before and after concrete was poured.

Midrails, screens, mesh, intermediate vertical members, solid panels, or equivalent intermediate members are installed between the walking-working surface and the top edge of the guardrail system as follows when there is not a wall or parapet that is at least 21 inches high. The opening limitation for guards is 19 inches.

Midrails should be placed midway between the top edge of the guardrail and the walking surface.

A toeboard should be placed at the walking surface. That toeboard should be a minimum 3-1/2 inches in height measured from the top edge of the toeboard to the level of the walking surface.

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