The International Building Code covers stairways primarily in Chapter 10 – Means of Egress, specifically under Section 1011 – Stairways. This section provides detailed regulations on stairway design, dimensions, safety features, and accessibility.
Key Aspects of Stairway Requirements in the IBC:
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Minimum Width (1011.2)
- Stairways must be at least 44 inches wide if serving an occupant load of 50 or more.
- If serving fewer than 50 occupants, the width can be 36 inches minimum.
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Headroom (1011.3)
- Minimum clear headroom of 80 inches (6 feet 8 inches) must be maintained throughout the stairway.
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Tread & Riser Dimensions (1011.5)
- Minimum tread depth: 11 inches.
- Maximum riser height: 7 inches.
- Minimum riser height: 4 inches.
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Stairway Landings (1011.6)
- Landings must be at least as deep as the stairway width but not less than 48 inches in depth.
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Handrails (1011.11, 1014)
- Required on both sides of the stairway.
- Height: 34-38 inches measured from the nosing of the stair treads.
- Extensions required at the top and bottom of stairs.
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Guardrails (1015)
- Required if the stairway is 30 inches or more above the floor.
- Guards must be 42 inches high with openings not exceeding 4 inches.
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Spiral Staircases (1011.10)
- Allowed for certain uses but must comply with specific size and design criteria.
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Emergency Egress Stairs (1023)
- Enclosed exit stairways must have fire-resistant construction, depending on building height and occupancy type.
