Connecting (Unenclosed) Stair Below Existing Skylight

[CAR]

We are proposing a new connecting stair at an existing sprinklered office high rise here in Chicago. The new open stair would connect the 39th and 40th floors (existing skylights above are outlined in red below). In Chicago we can do an 'open stair' between floors without the 2 hr. enclosure as long as the stair doesn't connect more than 2 floors in type IA and IIA sprinklered buildings. In this case being directly below the skylights our landlord rep is asking if there are any code issues given that glass could break and the fire spread could become worse. It's been a long time but I recall having done similar installations before without issues. I haven't come across any specific restrictions or issues with the proposed stair. I was wondering if anyone is aware of any code issues from an IBC or local code standpoint. Thx!

 

[ADAguy]

you say the glass could break? How old is the building? Glass isn't wired? Impact resistant?

 

[CAR]

you say the glass could break? How old is the building? Glass isn't wired? Impact resistant?

It's from the 1980s. We have not done a formal survey yet as we're still in the initial proposal phase. Breakage was just the concern raised by the client's rep.

 

[ADAguy]

On the right track, "need to verify".

 

[steveray]

Not a code section for the glass, but the 2 floor "gimmie" usually would require shaft protection if there are other openings on the floor....

1019.3 Occupancies other than Groups I-2 and I-3. In
other than Group I-2 and I-3 occupancies, floor openings containing
exit access stairways or ramps that do not comply
with one of the conditions listed in this section shall be
enclosed with a shaft enclosure constructed in accordance
with Section 713.
1. Exit access stairways and ramps that serve or atmospherically
communicate between only two stories.
Such interconnected stories shall not be open to other
stories.
2. 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 or sleeping unit or live/work unit.
3. Exit access stairways serving and contained within a
Group R-3 congregate residence or a Group R-4 facility
are not required to be enclosed.
4. Exit access stairways and ramps in buildings equipped
throughout with an automatic sprinkler system in
accordance with Section 903.3.1.1, where the area of
the vertical opening between stories does not exceed
twice the horizontal projected area of the stairway or
ramp and the opening is protected by a draft curtain and
closely spaced sprinklers in accordance with NFPA 13.
In other than Group B and M occupancies, this provision
is limited to openings that do not connect more
than four stories.