Fire separation distance and urban buildings with shared party walls

[drubinoff]

Hi,

I'm looking at an urban site where the new building will have its facade align with the facades of the neighboring buildings. I'm trying to understand if windows on my facade will be regulated by how close they are to neighboring aligned facades. When I look at the definition of FIRE SEPARATION DISTANCE in 2009 IBC §702, it says the distance shall be measured at right angles from the face of the wall. Its concept seems to speak of walls that are opposite my facade.

Is there something in the code that speaks to neighboring walls in line with my facade? If my building's exterior wall rating allows for a lot of glass on the facade, is there something to stop me from doing that within a certain distance of my party walls?

I'm thinking about how a fire could be blown from a neighboring window into my window from facades in a line on a windy day.

Thanks,

Derek

 

[brudgers]

So long as the design meets the requirements for party walls, no.

 

[RLGA]

A party wall is a wall that typically straddles the lot line and is shared by both buildings on each side of the lot line. Party walls are required to be constructed in accordance with the requirements for fire walls and may not have any openings.

If each building has its own exterior wall located at the lot line, then party wall (i.e. fire wall) requirements are not applicable, but fire-resistance per Table 602 and Section 705.5 (2009 IBC) is required.

Openings that are in walls that are situated 90-degrees or more from the lot line are not subject to Table 705.8, since, as you pointed out, the fire separation distance is measure perpendicular to the face of the exterior wall.