IBC 1023.7 - Interior exit stairways and exterior walls

[admiralArchArch]

I got flagged in permit review for not addressing this section of 2018 IBC. I have a type VA building with 1-hour exterior bearing walls and 2-hour shafts (4 story R2 on 1 story S-2 garage).

Does 1023.7 apply if my walls are already 1-HR per table 601 and 705.5? What about the openings? Could the 10' distance rule be omitted if the stair enclosure had 3/4 hr protected openings?

Situation similar to below:
Thanks y'all.

 

[RLGA]

Three things:

1. The walls around the stairs do not need to be 2-hour fire barriers if they are exterior walls. They only need to be rated if required by the fire separation distance.
2. The wall between the stairs and the interior of the building must be 2-hour fire barriers with no openings other than exit doors to access the stairway. Fire-protected-rated openings are not permitted. You can use fire-resistant-rated glazing systems with a 2-hour rating and tested per ASTM E119 or UL 263.
3. The opening on the right does not need to be fire-protection rated.

 

[admiralArchArch]

Three things:

1. The walls around the stairs do not need to be 2-hour fire barriers if they are exterior walls. They only need to be rated if required by the fire separation distance.
2. The wall between the stairs and the interior of the building must be 2-hour fire barriers with no openings other than exit doors to access the stairway. Fire-protected-rated openings are not permitted. You can use fire-resistant-rated glazing systems with a 2-hour rating and tested per ASTM E119 or UL 263.
3. The opening on the right does not need to be fire-protection rated.

Thank you for the reply. What is your reasoning on that the exterior window on the right does not need to be protected per 1023.7? Does this condition not match condition 1 in the code commentary? Or is it because the exterior walls are already rated 1023.7 doesn't apply?

 

[RLGA]

Thank you for the reply. What is your reasoning on that the exterior window on the right does not need to be protected per 1023.7? Does this condition not match condition 1 in the code commentary? Or is it because the exterior walls are already rated 1023.7 doesn't apply?

Only if the angle is less than 180 degrees, the wall shown is 180 degrees from the stairs--not less than.

 

[Yankee Chronicler]

Only if the angle is less than 180 degrees, the wall shown is 180 degrees from the stairs--not less than.

WHAAAT???

The window on the right is 90 degrees from the stair, not 180 degrees.

 

[RLGA]

WHAAAT???

The window on the right is 90 degrees from the stair, not 180 degrees.

EDIT: Maybe I'm not interpreting the drawing correctly--if the stair is internal to the building, then yes, it is less than 180 degrees. I was interpreting the drawing as if the stair enclosure was outside of the exterior walls (i.e., an addition to the building).

 

[admiralArchArch]

EDIT: Maybe I'm not interpreting the drawing correctly--if the stair is internal to the building, then yes, it is less than 180 degrees. I was interpreting the drawing as if the stair enclosure was outside of the exterior walls (i.e., an addition to the building).

Yes, sorry if it wasn't clear, this is an interior stair. Revised for clarity.
With that, then what is your response? If my exterior bearing walls are rated due to table 601, is any further action required?

 

[LR419]

The exterior is at the bottom left of the drawing? I was also looking at it the other way.

I would interpret the phrase "nonrated walls OR unprotected openings" in 1023.7 to mean that you need opening protectives on one window or the other, but not both.

 

[RLGA]

Yes, sorry if it wasn't clear, this is an interior stair. Revised for clarity.
With that, then what is your response? If my exterior bearing walls are rated due to table 601, is any further action required?

In that case, what you have shown would comply; however, the window at the exterior wall of the stair enclosure does not need to be rated unless it is required to be rated based on fire separation distance.

 

[Yankee Chronicler]

As originally shown, I don't think it complies. The stair enclosure is a 2-hour rated enclosure (except for the bottom one in the plan, with the windows in it), but the other exterior walls are only 1-hour. Either the fourth wall of the stair enclosure has to be increased to a 2-hour rating, or the two flanking walls have to be increased to 2-hour ratings.

 

[RLGA]

As originally shown, I don't think it complies. The stair enclosure is a 2-hour rated enclosure (except for the bottom one in the plan, with the windows in it), but the other exterior walls are only 1-hour. Either the fourth wall of the stair enclosure has to be increased to a 2-hour rating, or the two flanking walls have to be increased to 2-hour ratings.

Per IBC Section 1023.7, any walls less than 180 degrees from the non-rated (or, in this case, less-rated) exterior wall of the stair enclosure only need to have a 1-hour rating with 3/4-hour protected openings within 10 feet horizontally from the non-rated/less-rated exterior wall.

 

[Yankee Chronicler]

Per IBC Section 1023.7, any walls less than 180 degrees from the non-rated (or, in this case, less-rated) exterior wall of the stair enclosure only need to have a 1-hour rating with 3/4-hour protected openings within 10 feet horizontally from the non-rated/less-rated exterior wall.

Whoops. Forgot about that. Thanks.

1-hour it is.

 

[admiralArchArch]

Per IBC Section 1023.7, any walls less than 180 degrees from the non-rated (or, in this case, less-rated) exterior wall of the stair enclosure only need to have a 1-hour rating with 3/4-hour protected openings within 10 feet horizontally from the non-rated/less-rated exterior wall.

Whoops. Forgot about that. Thanks.

1-hour it is.

Thanks All, I think in my situation the less impact is to remove the windows in the stair towers so I don't need to protect the adjacent windows/storefront.

 

[admiralArchArch]

@RLGA, @Yankee Chronicler: Do you think the walls clouded in blue (segment 2) are subject to 1023.7 in this example? The wall is not in the same plane as segment 4, but is 180 degrees with respect to segment 1&3. The opening in segment 2 wants to remain and remain unprotected.