R2 - Type VA - Exterior door ratings - Exterior Stair Classification

[ccbdiver]

I have a 3 story R2 project, designed as type V-A construction fully sprinkled. It is on the smaller side so each level only has 4 units that open directly to a 8'x8' area then directly to the 1 exterior egress stair. The stair is completely open on 1 side and bound by exterior walls on most of the other 3 sides. All walls are 1 hr rated as required by table 601. SC 2021 IBC.

2 Questions:

1. What is the classification of this space outside the units? Is this considered an exterior corridor (open or breezeway), or something else? I'm having a hard time determining if this area falls into the 'rated exterior walls w/no protected openings', exterior corridor, or a exit access stair part of the code. It would be such a low occupancy regardless.

2. Do the unit doors need to be rated that open to this area? I feel like we have always had these as 20 min rated doors, but such a small exterior space I wonder if it really needs any rating and is more 'unprotective opening' territory. Or worst case is now forced to be 1 hr rated because of proximity to stairs with less hallway.

Thank you for any clarity you can share.

 

[Yankee Chronicler]

A plan would be helpful. From your description, it is not clear if this 8' x 8' area is indoors or outdoors, and whether or not there is a door between this 8' x 8' space and the exterior stair.

In general, there are three parts to the means of egress: exit access, the exit, and exit discharge. If this 8' x 8' space is outdoors, I propose that it may be an "Egress Balcony," which is addressed by section 1021 of the IBC. But I think egress balconies more properly apply to buildings such as low-rise motels that have a long balcony providing access to and egress from all the sleeping rooms. With dimensions of 8' x 8', yours can;'t be said to have a long dimension.

If it's not an egress balcony, is it simply a large stair landing? In that case, it's part of the exterior exit stairway and has to comply with IBC section 1027. The stair (including landings) and everything within ten feet of the stair must be separated from the interior of the building as required by section 1023.2. "Openings
shall be limited to those necessary for egress from normally occupied spaces."

There are exceptions to 1027.6 that may apply to your specific situation.

 

[steveray]

Floor plan necessary...And Welcome to THE Forum....

 

[ccbdiver]

Here is basic plan of area, both 8x8 area and stair are open, both to the exterior and each other. Seems like a common set up in small multi-family, just can't really find a great place in code for where it would to fit.

 

[classicT]

I'd classify that as an exterior exit stairway, with the area labeled "Exterior Space" being the intermediate landing for the stairway. Being open on only one side, it is not a breezeway.

Applicable code section for separation is as follows. Yes, the unit entry doors need to be rated.

2021 IBC 1027.6 Exterior Exit Stairway and Ramp Protection​

Exterior exit stairways and ramps shall be separated from the interior of the building as required in Section 1023.2. Openings shall be limited to those necessary for egress from normally occupied spaces. Where a vertical plane projecting from the edge of an exterior exit stairway or ramp and landings is exposed by other parts of the building at an angle of less than 180 degrees (3.14 rad), the exterior wall shall be rated in accordance with Section 1023.7.
Exceptions:

1. Separation from the interior of the building is not required for occupancies, other than those in Group R-1 or R-2, in buildings that are not more than two stories above grade plane where a level of exit discharge serving such occupancies is the first story above grade plane.
2. Separation from the interior of the building is not required where the exterior exit stairway or ramp is served by an exterior exit ramp or balcony that connects two remote exterior exit stairways or other approved exits with a perimeter that is not less than 50 percent open. To be considered open, the opening shall be not less than 50 percent of the height of the enclosing wall, with the top of the openings not less than 7 feet (2134 mm) above the top of the balcony.
3. Separation from the open-ended corridor of the building is not required for exterior exit stairways or ramps, provided that Items 3.1 through 3.5 are met:
   
   1. The building, including open-ended corridors, and stairways and ramps, shall be equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2.
   2. The open-ended corridors comply with Section 1020.
   3. The open-ended corridors are connected on each end to an exterior exit stairway or ramp complying with Section 1027.
   4. The exterior walls and openings adjacent to the exterior exit stairway or ramp comply with Section 1023.7.
   5. At any location in an open-ended corridor where a change of direction exceeding 45 degrees (0.79 rad) occurs, a clear opening of not less than 35 square feet (3.3 m2) or an exterior stairway or ramp shall be provided. Where clear openings are provided, they shall be located so as to minimize the accumulation of smoke or toxic gases.
4. In Group R-3 occupancies not more than four stories in height, exterior exit stairways and ramps serving individual dwelling units are not required to be separated from the interior of the building where the exterior exit stairway or ramp discharges directly to grade.

1023.2 Construction​

Enclosures for interior exit stairways and ramps shall be constructed as fire barriers in accordance with Section 707 or horizontal assemblies constructed in accordance with Section 711, or both. Interior exit stairway and ramp enclosures shall have a fire-resistance rating of not less than 2 hours where connecting four stories or more and not less than 1 hour where connecting less than four stories. The number of stories connected by the interior exit stairways or ramps shall include any basements, but not any mezzanines. Enclosures for interior exit stairways and ramps shall have a fire-resistance rating not less than the floor assembly penetrated, but need not exceed 2 hours.
Exceptions:

1. Interior exit stairways and ramps in Group I-3 occupancies in accordance with the provisions of Section 408.3.8.
2. Interior exit stairways within an atrium enclosed in accordance with Section 404.6.
3. Interior exit stairways in accordance with Section 510.2.