Open Stair as Egress

[jl3]

Hi All,

We have an office building, B occupancy, under IBC 2018, fully sprinklered, 3 stories, about 30k SF per floor with under 250 occupants per floor. We're providing 2 egress stairs, one that would be enclosed, but were wondering if the other stair could be "open" between the 3 floors. Provided that the travel distance was under 300' per table 1017.2 from a remote corner of the 3rd level to the exterior doors at the entry lobby, would we be good?

 

[RLGA]

No. Refer to Section 1006.3.1, which allows the path of travel to an exit to pass through no more than one story.

You can have an unenclosed exit access stairway from the 3rd story to the 2nd story that leads to an exit stair on the 2nd story (but not the same stair that provides the enclosed exit from the 3rd story).

Another option is to provide two enclosed exit stairs and one unenclosed stairway connecting all three stories complying with Section 1019.3, condition 4.

 

[steveray]

Atrium?

 

[mark handler]

Atrium?

Stairs in Atriums are not "Exit access stairways", you would need to add an additional complying stair, or, as Ron pointed out "... provide two enclosed exit stairs and one unenclosed stairway connecting all three stories complying with Section 1019.3, condition 4...."

 

[RLGA]

Stairs in Atriums are not "Exit access stairways", you would need to add an additional complying stair, or, as Ron pointed out "... provide two enclosed exit stairs and one unenclosed stairway connecting all three stories complying with Section 1019.3, condition 4...."

Actually, an atrium stair can be an exit stairway as added in the 2015 IBC, Section 1023.2, Exception 2. However, what is not clearly stated is that the atrium stair must comply with all other requirements for interior exit stairways (e.g., identification signs, standpipes at intermediate landings, etc.).

 

[Tim Mailloux]

without seeing plans, the OP's description sounds like an atrium to me

 

[RLGA]

without seeing plans, the OP's description sounds like an atrium to me

It could be, but with three stories, some form of smoke control will be required, plus the other exit stairway requirements that I mentioned.

 

[steveray]

Yep....a lot more complicated than an open 3 story stair.....