Fire Separation Distance

[Joe.B]

I am being questioned on a code interpretation and my boss suggested I check and see how others are interpreting this before I dig my heels in too deep. Here’s the definition I’m looking at, it’s the same in the building and residential code.

FIRE SEPARATION DISTANCE. The distance measured from the building face to one of the following:
1. The closest interior lot line.
2. To the centerline of a street, an alley or public way.
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 proposed project has basically a nearly zero setback from a rear property line that abuts an alley and side setback that abuts a public street. My interpretation is that the two walls need a one-hour rating due to their proximity to the property lines. The designer is arguing that they don’t need the rating because they have the distance to the centerline of the street/alley. What’s your take on that?

 

[redeyedfly]

You are incorrect. I have never once seen this interpreted otherwise. What is your argument that you get to ignore #2?

 

[Joe.B]

"The distance measured from the building face to one of the following:"

I have no problem being challenged and I don't mind being told I'm wrong. If I'm asked to make a determination I'm always going to error on the side of caution.

What's your argument for ignoring #1?

I see #2 being there for situations where the "alley or public way" is on private property.

 

[Yankee Chronicler]

The side setback abuts a public street, so there's no question in my mind that this one is measured to the centerline of the street. And by "street" I would use the deeded street right-of-way, not the centerline of the pavement (which may or may not be centered in the right-of-way).

The rear property line is the question. You said it abuts an alley, and the same code section that applies to streets also applies to alleys. How is the alley defined? Is it a deeded public way, is it a permanent easement over private property, or is it private property on which a new structure could be built at any time?

The code says the fire separation distance shall be measured to "one" or the following. t doesn't say it must be to the most restrictive. Remember, condition #1, which appears to be what you are relying on, says "interior lot line." An interior lot line is a property line that defines where two parcels directly touch. If there is a street or other right-of-way along a property line, it isn't an "interior" lot line.

It the alley is a defined, legal right-of-way, then it's clearly not an interior lot line. If the alley runs on private property but in/through an easement, then it becomes a gray area. Technically, that would be an interior lot line. However, if there's a permanent easement or right-of-way precluding ever building something there, then I would treat it the same as a street.

 

[Yankee Chronicler]

"The distance measured from the building face to one of the following:"

I have no problem being challenged and I don't mind being told I'm wrong. If I'm asked to make a determination I'm always going to error on the side of caution.

What's your argument for ignoring #1?

If a property line runs along a street, alley, or public way, it's not an "interior" lot line. Determing that it doesn't apply is not ignoring it, its determining that it doesn't apply.

I see #2 being there for situations where the "alley or public way" is on private property.

But number 2 include streets. Street don't run on private property (usually).

 

[redeyedfly]

"The distance measured from the building face to one of the following:"

I have no problem being challenged and I don't mind being told I'm wrong. If I'm asked to make a determination I'm always going to error on the side of caution.

What's your argument for ignoring #1?

I see #2 being there for situations where the "alley or public way" is on private property.

A public way on private property? No Stop and think about why this code provision exists instead of reading words in a vacuum.

You always get half the street. As you pointed out, it doesn't say to measure to the closest, just pick one. The AHJ doesn't get to pick, the RDP does.

The RDP is correct and is now sharing this story with the rest of their office while bracing for what is likely to be a long project with this AHJ.

 

[steveray]

The public way generally does not get built on which is why you get to impinge on it and why it is "interior" lot line and not just lot line....

 

[mtlogcabin]

Streets and alley's can be privately owned or publicly owned, If privately owned it is typically owned by the adjoining property owner to the center of the easement that allows it to be used by the public. Or they can be owned by the HOA but they are still dedicated as an easement for public/utility use.
Therefore it is assumed no structure will ever be erected on that ROW.

 

[MtnArch]

Our house (semi-attached, "duet" per the builder .. duplex to me) has an alley-loaded garage, and the alley connects to a public side street. Our property line at the alley is at the center and there is an easement for that area to allow access by the other residents who back onto that alley, with the HOA maintaining the alley - which is MLC mentions above.