Frontage

[Sifu]

So that means you’re using 2021 IBC, but the applicant has submitted a plan using the 2018 IBC method - are you in a transition period that allows the designer to comply with either code? Table 506.3.3 says interpolation is permitted, it doesn’t say calculation per the 2018 IBC method is permitted.

Correct, they appear to want to have it both ways. But to be fair, so would I. However code has no provision for this. There is no transition period, this AHJ has been on the '21 for years.

I think it precludes anything on the far side of the reduced width from being considered frontage:

1. 2021 IBC 506.3.1 requires perimeter to be accessed from a street or fire line. Implied in my opinion is that the entire access path be open space per 506.3.2.
2. 2021 IBC 506.3.2 says minimum width of the open space is 20’.

Agree, though I am questioning the viability of all of it.

Nice catch, shows you’re doing a thorough review.

Thanks. I was really hoping this project would be better, but the more I dig, the lass confident I become...so the more I dig.

 

[Tim Mailloux]

Because the interior perimeter of the doughnut is not available for firefighter operations..Because that is the intent…

Read it like this a little…

506.3.1​

To qualify for an area factor increase based on frontage, a building shall have not less than 25 percent of its perimeter on a public way or open space.

If the space doesn’t have direct access from a street or fire lane it doesn’t count…IMO

I always always include courtyards into the total perimeter number, and not count any of that courtyard perimeter as frontage. My approach is actually more conservative. Same with fire walls, I count the fire walls as building perimeter with zero frontage.

 

[Sifu]

I always always include courtyards into the total perimeter number, and not count any of that courtyard perimeter as frontage. My approach is actually more conservative. Same with fire walls, I count the fire walls as building perimeter with zero frontage.

That is the way I have always done it using 2018. But I've been wrong before. In this case, steveray's way would seem to penalize them for leaving a lilttle section open over enclosing it entirely.

2021 IBC with the new table instead of the old equation is somewhat less descriptive since it doesn't use "P= Perimeter of the entire building (feet)" as the 2018 did.

As skeptical and distrustful of "AI" as I am.... when I ask the question it says to use the outer P, and add the inner courtyard wall P. Where it comes up with this is a mystery so I can't pick and choose my skepticism and just accept what it says to suit my own perception.