The Height of Stairs

IBC

• The main charter of the International Code Council is to define construction standards useful to governments and construction companies that “benefit public safety.” Its International Building Code, or IBC, is in use either directly or with some modification by jurisdictions across the United States up to the federal level, including the Architect of the Capitol and the National Park Service. This member organization was founded in 1994 and defines such standards as the International Fire Code, the International Property Maintenance Code and the International Existing Building Code, which can affect the height of stairs.

Heights

• According to Section 1009 of the 2012 IBC, stairways need a minimum headroom clearance of 80 inches, which must be continuous above the stairway and any landings, across the full width of the stair. Spiral staircases can have a 78-inch clearance. Risers must be between 4 and 7 inches as measured from the nosings of adjacent treads. A flight of stairs (which is an unbroken run of steps), must not have a vertical rise over 12 feet before encountering a landing or a floor.

Handrails

• Handrails protect individuals from falling off but only if they are of the correct height. Section 1012.2 defines that height to be between 34 and 38 inches. It must be continuous above the stair tread nosings. Circular handrails must have a diameter of 1.25 to 2 inches. Noncircular ones require perimeter dimensions of between 4 and 6.25 inches, with a cross-section of between 1 and 2.25 inches. They must be continuous, without interrupting posts or bumps. Noncontinuous rails are only permitted between flights and only if the rail extends at least 12 inches beyond the top riser, and in the same direction as the run of steps.

Disabilities

• The Americans with Disabilities Act defines the IBC codes more specifically so that stairways remain accessible to people with physical handicaps. For example, risers must also be between 4 and 7 inches high, but must be uniform across all steps in one flight. Continuous handrails are required on both sides of a stairway, at a consistent height of between 34 and 38 inches above the walking surface. Their gripping surfaces must not be obstructed along their tops or sides, and may be obstructed at their bottom areas only for under 20 percent of their length.