STAIR-IBC CODE COMPLIANT

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The number of occupants on each floor will determine the required width of the stairs. In short, the width is calculated by multiplying the occupant load served by such stairs by a factor of 0.3 inch per occupant. However, the very minimum width between handrails is 44 inches. You must calculate the IBC stair width for multi-story stairways versus single-story stairways.Riser Height and Tread DepthThe step height, also known as the riser height, must be no less than 4 inches and no greater than 7 inches. The minimum tread depth is 11 inches. If the stairs have nosings, you measure from the leading edge of the nosing to the edge of the next step’s nosing.Guards Guards are required along all open-sided walking surfaces of the stairway, including landings and stairs. The guard height must be at least 42 inches high, and it is measured vertically from the leading edges of the tread nosings or from the landing surface. Any spacing in the guards must be less than 4 inches. Shown below, the guards are vertical balusters, but guards can also be pieces of glass, wire, etc.Handrails Handrails must be on both sides of the IBC stairs, and they must comply with these additional handrail requirements. You could compare all the ADA, OSHA and IBC stair railing height requirements here.