Counterbalanced emergency exit stair

[BayPointArchitect]

For the past ten years, I have made reference to the counterbalanced stairs as "antiques that are fun to look at but not allowed for new construction". And now I am being challenged by the question, "where in the code book does it say that those stairs are not allowed?".

After reading chapters 7 and 8 of the Life Safety Code, I see everything that would require stair shafts to be fire-rated except for a stairway that is not a required means of egress. Nothing there to say that the stairway needs to be fixed in place and immobile.

IBC 1009.9 Stairway construction shall include materials consistent with the types permitted for the type of construction of the building...

And we have the exceptions spelled out for spiral stairways, alternating tread devices, ship ladders, and stairway to the roof. Nothing there to say that counterbalanced stairs are acceptable or prohibited.

And when the manufacturer of a counterbalanced stairway tells me that they sell these all over the country, that does not give me the code-compliant credibility that I am looking for. However, these stairs do have a 7 inch riser and 11 inch tread. That's good. And they custom build these stairs according to the 36 inch minimum width or 44 inch minimum width. That's good too.

If you had to install one of these to serve as either your primary or secondary exit, what would you say to the inspector that says, "I just don't like it"?

Thanks!

ICC Certified Plan Reviewer
NFPA Certified Fire Plan Examiner

 

[mtlogcabin]

2012 IEBC & 2012 IBC
405.1 Where permitted.
Fire escapes shall be permitted only as provided for in Sections 405.1.1 through 405.1.4.

405.1.1 New buildings.
Fire escapes shall not constitute any part of the required means of egress in new buildings.

405.1.2 Existing fire escapes.
Existing fire escapes shall continue to be accepted as a component in the means of egress in existing buildings only.

405.1.3 New fire escapes.
New fire escapes for existing buildings shall be permitted only where exterior stairs cannot be utilized due to lot lines limiting stair size or due to the sidewalks, alleys or roads at grade level. New fire escapes shall not incorporate ladders or access by windows.

405.1.4 Limitations.
Fire escapes shall comply with this section and shall not constitute more than 50 percent of the required number of exits nor more than 50 percent of the required exit capacity.

405.2 Location.
Where located on the front of the building and where projecting beyond the building line, the lowest landing shall not be less than 7 feet (2134 mm) or more than 12 feet (3658 mm) above grade, and shall be equipped with a counterbalanced stairway to the street. In alleyways and thoroughfares less than 30 feet (9144 mm) wide, the clearance under the lowest landing shall not be less than 12 feet (3658 mm).

405.3 Construction.
The fire escape shall be designed to support a live load of 100 pounds per square foot (4788 Pa) and shall be constructed of steel or other approved noncombustible materials. Fire escapes constructed of wood not less than nominal 2 inches (51 mm) thick are permitted on buildings of Type V construction. Walkways and railings located over or supported by combustible roofs in buildings of Type III and IV construction are permitted to be of wood not less than nominal 2 inches (51 mm) thick.

405.4 Dimensions.
Stairs shall be at least 22 inches (559 mm) wide with risers not more than, and treads not less than, 8 inches (203 mm) and landings at the foot of stairs not less than 40 inches (1016 mm) wide by 36 inches (914 mm) long, located not more than 8 inches (203 mm) below the door.

405.5 Opening protectives.
Doors and windows along the fire escape shall be protected with 3/4-hour opening protectives.

2012 IFC
1104.16.6 Termination.
The lowest balcony shall not be more than 18 feet (5486 mm) from the ground. Fire escape stairs shall extend to the ground or be provided with counterbalanced stairs reaching the ground.

Exception: For fire escape stairs serving 10 or fewer occupants, an approved fire escape ladder is allowed to serve as the termination.