Note that when looking for commercial stair standards one must look at the international building code ibc.
Ibc stairway roof.
These landings should be the same width as the stairway and extend at least three feet in length.
Handrail height measured above stair tread nosing s or finish surface of ramp slope shall be uniform not less than 34 and not more than 38.
The only apparent purpose of the stair is not to provide a means of egress to the roof level but to provide access to the roof for the maintenance of equipment.
Stairs that are higher than 12 feet tall require an intermediate landing in the middle of the stairway.
The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.
The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process.
Stair riser heights shall be 7 inches 178mm maximum and 4 inches 102mm minimum.
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.
In this post we will be looking at the code standards related to residential stairs in accordance with the international residential code irc.
1011 12 stairway to roof in buildings four or more stories above grade plane one stairway shall extend to the roof surface unless the roof has a slope steeper than four units vertical in 12 units horizontal 33 percent slope.
Stairway rise ibc 1011 8 every 12 feet of vertical rise the stairway must have a landing.
Access to setback roof areas may be through a door or window opening to the roof.
Rectangular tread depths shall be 11 inches 279 mm minimum measured horizontally between the vertical planes of the foremost projection of adjacent treads and at a right angle to the tread s nosing.
Walking surface ibc 1011 7 1 the slope of the walking surface cannot be greater than 1 48 in any direction.