Roof Access Stair Requirements

Spiral stairs must meet the vertical clearance requirements in paragraph d 3 of this section.

Roof access stair requirements. Vertical clearance above any stair tread to any overhead obstruction is at least 6 feet 8 inches 203 cm as measured from the leading edge of the tread. Individual rung step ladders must extend at least 42 inches 1 1 m above an access level or landing platform either by. In buildings four or more stories or more than 40 feet 12 192 mm in height above grade one stairway shall extend to the roof surface through a stairway bulkhead complying with section 1509 2 unless the roof has a slope steeper than 20 degrees 0 35 rad. Free egress from the roof to the stairwell is required for occupied roofs but is not mandated by the ibc or nfpa 101 for unoccupied roofs.

Fixed ladders must be able to support at least two loads of 250 pounds 114 kg each concentrated between any two. Interior stairs shall terminate at the under side of the roof at a hatch or scuttle of at least 8 square feet 0 74 m 2 with a minimum dimension of 20 inches 508 mm. Access to setback roof areas may be through a door or window opening to the roof. 1910 25 b 3 stairs have uniform riser heights and tread depths between landings.

When unavoidable obstructions are encountered the minimum clearance at the obstruction may be reduced to 24 inches 61 cm provided deflector plates are installed see figure d 5 of this section. In summary free access to the roof from the stairwell is not required by the ibc or nfpa 101 but may be required or preferred by the local code official.