Fire Separation Distance

[dmhokie]

I am having trouble determining where to measure my fire separation distance in the small addition. This is a car service garage, and we are adding the small addition shaded yellow. The existing building has a wall on the property line with an overhead door where the red arrow is. The intent is to add the yellow addition with another overhead door with the red arrow. The blue dashed line above is the extent of the easement between the properties. So my question is if I have to measure my fire separation to the property line, which is more or less 0', or can I go to the centerline of the easement or alley?

 

[RLGA]

Centerline of easement/alley.

 

[CR Design]

As defined in the IBC 2024 (and all previous editions):
FIRE SEPARATION DISTANCE. The distance measured from the building face to one of the following:

1. 1.The closest interior lot line.
2. 2.To the centerline of a street, an alley or public way.
3. 3.To an imaginary line between two buildings on the lot.

The distance shall be measured at right angles from the face of the wall.
The FSD in this case would be to the property line (Item 1).
In the State of Wisconsin, an amendment was crafted to also include "A permanent no-build easement line" in the definition.
The local AHJ may accept the easement line (blue dashed line) as the FSD if there is no local amendment. Otherwise, the FSD is 0'-0" for a portion of the proposed addition. This will impact the exterior wall construction as well as opening limitations.

 

[walker.t]

or can I go to the centerline of the easement or alley?

If you take the fire separation distance to the centerline of the easement you need to make sure that your easement meets the requirements of the definition of a public way in IBC Chapter 2:

1. Open to the outside air. I assume so if you have overhead doors opening to the easement.
2. Leads to a street. I can’t tell by what you show.
3. Deeded, dedicated, or otherwise permanently appropriated to the public for public use. Can someone walking their dog go down your easement without permission or is it private property?
4. Clear width and height of not less than 10’. Width looks good, I assume height is OK if you have overhead doors.