Hello,

I'm working on a new office buildout for a tenant (business occupancy). It's in an existing building - Type IIIB construction (masonry exterior walls, wood frame floor structure). The building is 3 stories + a basement. There is an existing tenant (business occupancy too) occupying all of the 2nd & 3rd floor and part of the 1st floor with shared common areas in a portion of the basement. This new tenant (which actually has a working business relationship with the existing tenant) will be occupying the remainder of the 1st & basement levels. They will have their own front & rear exits at the main floor level and the basement has 2 means of egress through common areas. The entire building IS sprinklered and we more than meet all of our common path of travel, dead-end corridor, and travel distance requirements. The entire building is about 17,800 s.f. (total occupant load of 179 people) and this new tenant space comprises about 5,300 s.f. of that (and about 53 people of the total occupant load).

My question comes in that we would like to add a new open communicating stair connecting the 1st floor and basement areas of the new tenant space (new tenant space is separated from the existing tenant space and common areas, though no fire rating is required of this separation per 2006 IBC). This communicating stair will not be required to act as one of our means of egress as we have sufficient egress already from the basement. At the main floor, the communicating stair would open up into a wide hall with a small open seating area, access to a break area, and doors going into offices. At the lower floor it's a similar thing - the stair dumps out into a wide open hallway with offices off of it. The stair would be open on 3 sides at each floor.

In 2000 NFPA, section 8.2.5.5 states that unenclosed floor openings forming a communicating space between floors is permitted if it meets the following requirements:
1) Doesn't connect more than 3 stories (we're good)
2) Lowest or next to lowest story is street floor (we're good)
3) Entire floor area of the communicating space is open and unobstructed such that a fire in any part of the space will be readily obvious (hmm?)
4) If sprinklered, communicating space is separated from remainder of building by smoke barrier (ok, I suppose...)
5) Space has ordinary hazard and sprinklered (yep)
6) Egress capacity is sufficient to provide for all occupants to simultaneously egress the communicating space (sure)
7) Occupants not in communicating space has access to no less than one exit without entering communicating space (hmm?)

I know I've designed and built tenant office spaces before that were sprinklered and had a communicating stair that was open to wide corridors and had offices or suites off of that corridor and it wasn't a problem. And I know I've been in plenty of offices with similar configurations. But reviewing this section of the code is making me a bit confused again and I wanted to see if anyone else had some thoughts to add.

I guess my big questions are with #3, #4, and #7.

With #3, What defines entire floor area being open to the communicating space? Does that mean I can't have offices or suites off of this open communicating area? That can't be right as I know I've seen this type of setup a zillion times?? At the first floor, the wide open hallway (ranges from 10' to 16' wide) at the stair merges right into a narrower hallway (but still at least 5' wide) that leads to the reception/waiting area and front door. If I'm standing in the reception area, I could look straight down the hallway and see all the way down to the stair area (though I can't do that if I'm standing directly at the front door - it's like a cased opening connecting the hall and the reception area). Is this considered un-open? Are they saying they only would accept vast areas of cubicles to be open to a communicating space but no offices w/ doors? Feeling confused.

With #4, if they are saying it's ok to have offices off of this area, are they saying all the offices would have to have a smoke barrier? We were hoping to do sliding glass doors or sliding barn doors into the conference room - but I don't think they would meet the requirements of a smoke barrier. I suppose if we have to, we can go with a different door system that doesn't leave any gaps more than 1/8" but again, that seems excessive for this project type.

And then with #7, the part about occupants not in the communicating space having access to an exit without entering the communicating space - are they saying that someone in an office off of the communicating space has to have a separate exit out of their space that doesn't pass through the communicating hallway?? That can't be right - half our space would be taken up with secondary corridors!

All of these potential interpretations just seem way too extreme for a 5,300 s.f. sprinklered business occupancy space. I'm hoping that someone can lend some insight that makes more sense. Perhaps the communicating space is actually defined as the entire 1st floor new tenant space communicating to the entire basement area of the new tenant space, regardless of any internal offices or rooms? Maybe just looking at the overall tenant demising walls? There's got to be something here that I'm missing that explains why there are a plenty of tenant office spaces that have communicating stairs that open up to corridors with offices off them.

Thoughts anyone??

-LMD