Roof Access Stair Requirements

1910 25 b 3 stairs have uniform riser heights and tread depths between landings.

Roof access stair requirements.

Spiral stairs must meet the vertical clearance requirements in paragraph d 3 of this section. 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. A minimum perpendicular distance of 30 inches 76 cm from the centerline of the steps or rungs to the nearest object on the climbing side. Access to setback roof areas may be through a door or window opening to the roof.

Individual rung step ladders must extend at least 42 inches 1 1 m above an access level or landing platform either by. 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. 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. 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.

Each step or rung of a fixed ladder must be able to. Fixed ladders must be able to support at least two loads of 250 pounds 114 kg each concentrated between any two.