stair design to access an industrial platform

[joetheinspector]

I have a stair design to access an industrial platform for infrequent maintenance access that has an approximate rise of 40 degrees from the horizontal. This design fulfills the OSHA requirements for fixed industrial stairs (OSHA 29 CFR 1910.24(e)) for the angle of the stair rise to the horizontal to be between 30 and 50 degrees.

the IBC 2003 section 1009 for the design of stair treads and risers. The IBC states that the stair riser height shall be a maximum of 7” and the stair tread depth shall be a minimum of 11”. This combination allows for a maximum of 32.5 degrees from the horizontal.

My question is, if there is an exception to the IBC to allow for greater stair rise angle for maintenance access as opposed to operational egress access as shown in the IBC Code?

 

[JBI]

Re: stair design to access an industrial platform

2003 IBC 1009.10 Alternating tread devices.

Alternating tread devices are limited to an element of a means of egress in buildings of Groups F, H and S from a mezzanine not more than 250 square feet (23 m2) in area and which serves not more than five occupants; in buildings of Group I-3 from a guard tower, observation station or control room not more than 250 square feet (23 m2) in area and for access to unoccupied roofs.

Might not help you much, but the 2009 has:

1009.11 Ship ladders. Ship ladders are permitted to be used in Group I-3 as a component of a means of egress to and from control rooms or elevated facility observation stations not more than 250 square feet (23 m2) with not more than three occupants and for access to unoccupied roofs.

Ship ladders shall have a minimum tread depth of 5 inches (127 mm). The tread shall be projected such that the total of the tread depth plus the nosing projection is no less than 81/2 inches (216 mm). The maximum riser height shall be 91/2 inches (241 mm).

Handrails shall be provided on both sides of ship ladders. The minimum clear width at and below the handrails shall be 20 inches (508 mm).

1009.12 Handrails. Stairways shall have handrails on each side and shall comply with Section 1012. Where glass is used to provide the handrail, the handrail shall also comply with Section 2407.

Exceptions:

1. Handrails for aisle stairs are not required where permitted by Section 1028.13.

2. Stairways within dwelling units, spiral stairways and aisle stairs serving seating only on one side are permitted to have a handrail on one side only.

3. Decks, patios and walkways that have a single change in elevation where the landing depth on each side of the change of elevation is greater than what is required for a landing do not require handrails.

4. In Group R-3 occupancies, a change in elevation consisting of a single riser at an entrance or egress door does not require handrails.

5. Changes in room elevations of three or fewer risers within dwelling units and sleeping units in Group R-2 and R-3 do not require handrails.