Exterior exit stairway

[Sifu]

Interesting project hit my desk. 100 year old (plus) building. Proposed remodel includes B occupancies on the first and second floor. Not a big deal, but there is a proposed "future" pair of R3 units to be built later on the roof. This new 3rd floor needs a way down. I have a few concerns. 2018 IBC.

1) The single way off the roof with the proposed R3 units exceeds the EATD/CPET of 125'. I don't see a way around this if I read it correctly. Section 1006.2.2.6 limits the EATD to 125' for R3's. T1006.2.1 has a 125' max. CPET limit (and sends me back to 1006.2.2.6 for EATD), and 1006.3.3 refers to me to t1006.3.3(1) or (2). T1006.3.3(1) is not for R3 occupancies, t1006.3.3(2) is for all other occupancies.
NOTE: I am confused by tables 1006.3.3(1) & 1006.3.3(2). (1) is for stories with one exit for R2 occupancies, and (2) is for stories with one exit for other occupancies yet, it makes no mention of R3's, and does include some R2 occupancies.

2) The egress converges with the exterior exit stair from the adjacent lower roof. This convergence does not occur in the adjacent unit, only the landing from that other rooftop. Would this be compliant since it does not enter the "space"?

3) The limits for not protecting the exterior walls and openings adjacent to the exterior exit stair are 2-story for a B occupancy, and 4 stories for an R3 occupancy. Is it correct to say that the stair serves only a 2 story B, and a 3 story R3, therefore is compliant?

 

[Sifu]

Follow up: 1027.5 requires 10' separation from the adjacent building or lot line for all occupancies except the R3, which is 5', but only for the portion serving the R3. Wouldn't' that cause stairs for both buildings to be out of compliance unless rated as exterior walls even if the provisions for protection don't require ratings?

As far as exits off the 3rd floor/roof/R3, is it permitted no matter the travel distance by 1006.3.3 #4?

 

[Sifu]

Ok, not getting any interest in the first query, I'll try another wrinkle with this design:

With the dwelling units on the third floor (future), since there are only two, I think they are exempt from being type A or B units, and therefore exempt from an accessible route to that level. However, in a three story building where the area of each floor is 2500sf², the aggregate exceeds 3000sf² so the second floor would now be required to be accessible I think. Or does the fact that the third floor only contains non-accessible required dwelling units negate this requirement?

There are not shared, common areas on the third floor,.

 

[steveray]

Ok, not getting any interest in the first query, I'll try another wrinkle with this design:

With the dwelling units on the third floor (future), since there are only two, I think they are exempt from being type A or B units, and therefore exempt from an accessible route to that level. However, in a three story building where the area of each floor is 2500sf², the aggregate exceeds 3000sf² so the second floor would now be required to be accessible I think. Or does the fact that the third floor only contains non-accessible required dwelling units negate this requirement?

There are not shared, common areas on the third floor,.

If it is only dwelling units, and the dwelling units are exempt....I would say no route...1103 and 1104 and one of those sends you to the dwelling unit section, maybe 1107?

 

[Sifu]

Pretty confident the dwelling units are exempt. So I think that level is not required to have an accessible route. My question is does the 2nd level need one. In other words, do I completely ignore the area of the 3rd floor since it does not require an accessible route per exc. #2 and only use the area of the 2nd floor to determine the aggregate area in order to meet exception #1?