Fire Separation Distance

[nschultz]

I am trying to understand the fire-resistant rating to be applied to the exterior walls of two buildings.

I have a Type II-B F-1 occupancy building (1500sf) placed 5ft from a Type II-B F-2 occupancy building (1500sf). If I don't consider the two buildings as one per 503.1.2 then reading T 602 would require a 2 hr rated exterior wall on F-1 and a 1 hr rated exterior wall on F-2, correct? This is assuming that the imaginary lot line is halfway between the two buildings.

If I do consider the two buildings as one per 503.1.2 (well within T 503 allowables) and then read through Section 508, particularly 508.4, T 508.4 requires a 2 hr separation (NS). Am I interpreting this correct?

State adopts IBC 2012.

 

[nschultz]

Forgot to mention that I read through this thread first before posting. https://www.thebuildingcodeforum.co...e-buildings-as-one.7682/#commercial-codes.101

 

[steveray]

I would think you could do 1 building mixed use non-separated (all F1)at 3000 feet...No?

 

[classicT]

Shouldn't be a problem to consider it one building and provide no separation. (Mixed use, non-separated)

 

[classicT]

And welcome nschultz....

Hope that you continue to utilize this forum. If you do, make sure to join as a Sawhorse and help keep the forum alive.

 

[nschultz]

OK. I can change the selected option to mixed use non-separated. How does that change the fire resistant wall requirements? T 601 does not require exterior bearing walls to have fire resistant rating for Type IIB construction. Am I not required to meet requirements from T 602 because I did not choose separated occupancies option? Does the response change if I leave an actual 5ft gap between the two "buildings" and have exterior walls.

 

[Builder Bob]

Unless you are using the one building concept, then you would have to meet the requirements of T602 for fire separation distance.

 

[classicT]

OK. I can change the selected option to mixed use non-separated. How does that change the fire resistant wall requirements? T 601 does not require exterior bearing walls to have fire resistant rating for Type IIB construction. Am I not required to meet requirements from T 602 because I did not choose separated occupancies option? Does the response change if I leave an actual 5ft gap between the two "buildings" and have exterior walls.

As long as the buildings are on the same lot, then the provisions of non-separated mixed use buildings will ignore the gap between the buildings. Thus the two buildings are treated as one.

503.1.2 Buildings on Same Lot
Two or more buildings on the same lot shall be regulated as separate buildings or shall be considered as portions of one building where the building height, number of stories of each building and the aggregate building area of the buildings are within the limitations specified in Sections 504 and 506. The provisions of this code applicable to the aggregate building shall be applicable to each building.​

 

[nschultz]

Thanks a bunch!