Though stairways are complex structures requiring precision construction, they represent a mature technology that the building industry has mastered. To ensure safety and durability, contractors must follow the standards in the Ohio building code that define stair components such as rail height.
As part of the Ohio Department of Commerce, the Division of Industrial Compliance and Labor oversees the Bureau of Building Code Compliance. This state body "reviews building plans to insure compliance with the Ohio Building Code for new construction projects, along with major renovations, additions or alterations to existing structures." The codes come from the International Building Code, under the management of the International Code Council. This non-profit organization also handles the International Fire Code, International Energy conservation Code and the International Plumbing Code, which are in standard use by all construction jurisdictions in the U.S.
Handrails must be from 34 inches and 38 inches high as measured from the edge of the stair step or from the surface of an adjacent ramp slope. This measurement includes the length of the baluster or post, plus the thickness of the handrail. Type I handrails with a circular cross section must have an outside diameter of between 1.25 and 2 inches. Non-circular handrails need a perimeter of 4 to 6.25 inches, with a maximum cross-section of 2.25 inches. Type II handrails with a perimeter measuring over 6.25 inches require a recessed area on both sides of the profile that can be grasped.
Handrail height must be uniform across an entire flight of stairs and have gripping surfaces that cannot be interrupted by posts, balusters or other obstructions that are part of the handrail type. Handrails inside dwellings are an exception as they can be interrupted by a newel post at a landing or turn. Handrails require a minimum 1.5-inch clearance to an adjacent wall or surface. They can project into the clear width of a staircase a maximum of 4.5 inches. Wide stairs need intermediate handrails at the same height, so that all parts of the stairway are within 30 inches of a rail.
Handrails for spiral staircases must follow measurements for general staircases, unless specifically changed. In this case, spiral rails must be at the same height of 34 to 38 inches. Alternating tread devices are a special stairway with a series of alternating steps so users do not have both feet at the same level at once. For these structures, the handrail height must be between 30 and 34 inches.