Fire Separation distance less than 5', does that create a stepped building condition

[aztec]

I'm getting conflicting answers and thought I'd ask the forum. We have two buildings A and B. A is existing, B is new. Both are type IIB construction, occupancy H. The code official said due to building area limitations we need a fire separation wall between A and B (they intesect at one area). Got that part. However, there is a piece of B that does not touch A (FSD less than 5', actually 3"). At that particular location A's (exist) roof is higher than than B (new). A and B do not have any openings. I was told we should treat this condition as a stepped condition (706.6.1), and use SFRM for > 10' of the lower roof of B. Another guy said we do NOT have a stepped condition, however, we still need to rate B's (new) exterior wall (3 hr, both sides) and use SFRM for > 10'. When we looked in the code, we could not find something that described this condition.

My question is this: just because we are allowed to build right next to an existing building (we have the go for that) why is this a stepped condition? If it's not a stepped condition, then where does it tell me how to address the roof? Table 602 explains the fire resistance requirements for my exterior wall (at this particular location we have 30' of wall with a 3" FSD). Bottom line, I do not want to mess with the existing building at all (A). All the steel and foundation is up, so we are attempting to fix the situation. As I understand it, stepped condition is for fire wall - if I have a fire wall, then that's fine. I just do not understand why I am told to present a stepped condition to the city. If it's not a stepped condition, then what is it? I assume this sort of thing is done on the east coast...but I'm not from the east coast. Any suggestions would be great.

 

[Papio Bldg Dept]

'The fire separation distance does not a stepped building make.' The Code Yoda

From what you described, I understand you to be describing one building required to be separated into two buildings. The code says these are now two separate buildings, and in your case, each of these two adjacent and separate buildings will have different roof levels. That is what makes your buildings a stepped building.

 

[peach]

If it could be one building, and there isn't a property line, you can look at it as one building. Without knowing the sizes of the buildings, it's pretty hard to determine.

If a fire separation is indeed required, because of area limitations, the wall needs to continue above the higher building.