Exterior Egress Stair

[Ma2Arch]

Hi all--I'm using the 2018 IBC,
We have a 4 unit per floor, three story above podium apartment building with two exterior egress stairs. At a quick glance, I don't believe we can classify the corridor as an egress balcony (Section 1021) since it is not open enough, so the heavy red lines will need to be fire rated. I am assuming that the dashed lines will need to meet the opening requirements of 1027.3.

One thing has me stumped, the commentary says that "Exterior exit stairways or ramps between stories much comply with Section 1019.3..." but the exceptions in that section seemingly don't allow an open egress stairway.

First question: Am I correct in assuming that the exit corridor will need to be rated?
Second: What am I missing in the exceptions of 1019.3?

Thanks for your help!

 

[classicT]

Trash chute enclosed only on the three sides does not work.

But getting to your question... I'm not sure how you can propose to use exit access stairways. Per 1006.3.1, "The path of egress travel to an exit shall not pass through more than one adjacent story." To comply, you are likely going to need to provide exit access on each floor; meaning, either interior or exterior exit stairways. Given that you already are proposing exterior openings, I would presume that you will likely go with exterior exit stairways.

If so, see 1027.6 for the protection requirements. Take note of exceptions #2 and #3, otherwise it appears that you will need to enclose the stairs in a shaft.

2018 IBC 1006.3.1 Adjacent Story​

The path of egress travel to an exit shall not pass through more than one adjacent story.
Exception: The path of egress travel to an exit shall be permitted to pass through more than one adjacent story in any of the following:

1. In Group R-1, R-2 or R-3 occupancies, exit access stairways and ramps connecting four stories or less serving and contained within an individual dwelling unit, sleeping unit or live/work unit.
2. Exit access stairways serving and contained within a Group R-3 congregate residence or a Group R-4 facility.
3. Exit access stairways and ramps in open parking garages that serve only the parking garage.
4. Exit access stairways and ramps serving open-air assembly seating complying with the exit access travel distance requirements of Section 1029.7.
5. Exit access stairways and ramps between the balcony, gallery or press box and the main assembly floor in occupancies such as theaters, places of religious worship, auditoriums and sports facilities.

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.

 

[RLGA]

One thing has me stumped, the commentary says that "Exterior exit stairways or ramps between stories [must] comply with Section 1019.3..." but the exceptions in that section seemingly don't allow an open egress stairway.

You are missing a word in your quote: "Exterior exit access stairways or ramps between stories must comply with Section 1019.3..."

If your stairs are exterior exit stairways, Section 1019.3 does not apply.

 

[Yankee Chronicler]

Aside from the points already raised, how do those two stairs in any way satisfy requirements for remoteness of means of egress? If the area around the two stairs, outlined in dark red, is what you call the exit corridor, you have two open stairs served by the same corridor/atmosphere. Irrespective of whether or not those stairs otherwise qualify as exterior exit stairs (IMHO they don't), having two exits sharing the same atmosphere means you DON'T have two exits -- you have one exit with two stairways in it.

 

[classicT]

Aside from the points already raised, how do those two stairs in any way satisfy requirements for remoteness of means of egress? If the area around the two stairs, outlined in dark red, is what you call the exit corridor, you have two open stairs served by the same corridor/atmosphere. Irrespective of whether or not those stairs otherwise qualify as exterior exit stairs (IMHO they don't), having two exits sharing the same atmosphere means you DON'T have two exits -- you have one exit with two stairways in it.

I was wondering about that as well. Theoretically, they could have a single exit (or access to one exit) for the first, second, or third story above grade plane per Table 1006.3.3(1).

 

[Yankee Chronicler]

I think it would be helpful to see the overall floor plan. Are there other exits from the upper floors? Is the idea to provide one exit stair for each apartment?

 

[Yankee Chronicler]

For starters, you need to be looking at IBC section 1027 for exterior exit stairs. The IBC has a definition for exterior exit stairways:

EXTERIOR EXIT STAIRWAY. An exit component
that serves to meet one or more means of egress design requirements,
such as required number of exits or exit access travel
distance, and is open to yards, courts or public ways.

The IBC (2021) Commentray for this definition goes on to say:

Requirements for an exterior exit stairway are different
from those for an interior exit stairway. Exterior exit
stairways are typically outside of the building, provide
exits from above or below the level of exit discharge,
and are exposed to at least some elements of
weather. The protection requirements, therefore, are
for the exterior walls between the building and the
stairway, rather than interior walls. For the stairway
requirements, see Section 1011. For specifics for exterior
exit stairways, see Section 1027.

Before I even look at section 1027, the commentary tells me that the stair itself needs to be separated from ALL the interior portions of the building. The plan as proposed doesn't do this -- the stairs are open to the common corridor (or whatever it is). Then we move on to section 1027 ...

1027.3 Open side. Exterior exit stairways and ramps serving
as an element of a required means of egress shall be open on
not less than one side, except for required structural columns,
beams, handrails and guards. An open side shall have not less
than 35 square feet (3.3 m2) of aggregate open area adjacent to
each floor level and the level of each intermediate landing. The
required open area shall be located not less than 42 inches
(1067 mm) above the adjacent floor or landing level.

The plan appears to satisfy this requirement.

1027.4 Side yards. The open areas adjoining exterior exit
stairways or ramps shall be either yards, courts or public ways;
the remaining sides are permitted to be enclosed by the exterior
walls of the building.

1027.5 Location. Exterior exit stairways and ramps shall have
a minimum fire separation distance of 10 feet (3048 mm)
measured at right angles from the exterior edge of the stairway
or ramps, including landings, to:
1. Adjacent lot lines.
2. Other portions of the building.
3. Other buildings on the same lot unless the adjacent
building exterior walls and openings are protected in
accordance with Section 705 based on fire separation
distance.
For the purposes of this section, other portions of the building
shall be treated as separate buildings.
Exception: Exterior exit stairways and ramps serving individual
dwelling units of Group R-3 shall have a minimum
fire separation distance of 5 feet (1525 mm).

Not enough information provided to evaluate these requirements.

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.

The proposed plan clearly does not comply with this requirement. There are exceptions, which I haven't quoted, but none appear to apply in this situation.

 

[Ma2Arch]

Thank you all, you've confirmed what I've suspected. A couple of clarifications:

• The stairs do meet the remote requirement--in reality the diagonal of this building is not very big. We checked that first.
• There are four units per floor, and these two stairs are the means of egress for those units from each floor.
• The stairs are next to an alley and because this is a development, the lot lines are malleable. We have another building nearby, but I've emphasized that they need to be more than 10'-0" apart. The lot line will be next to the other building and we won't have any openings on that building's wall.
• The developers don't want to mechanically condition the hallway, thus the open corridor.
• The designers don't want to give up any space, hence the lack of a separation wall : (

I have a feeling that we don't meet the definition of Open Ended Corridor since there's no way there will be free air flow in this configuration (i.e. like a breezeway as noted in the definition) so we will be required to have doors into the stairs rather than just an opening. If I'm mistaken, please let me know. I realize that due to the change in direction we'll need a 35 s.f. opening.

So this is where we'll end up, but we just need to find some room for those extra walls: