Two Buildings - One Site

[TJ_Laccetti]

We have a project with two new buildings, designed as F-1 "Factories" on the same site, both with the same use. Each building is Type 2B Construction and Fully sprinkled at 76,500 SF each. They want to be 30 feet apart due to required access and outside equipment proximity. (It cannot be one building) Would the exterior walls need to be rated?

IBC 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 if the building height of each building and the aggregate building area of the buildings are within the limitations of Table 503 as modified by Sections 504 and 506. The provisions of this code applicable to the aggregate building shall be applicable to each building.

We noticed they did not list section 505 above for sprinkler area increase, so was that on purpose?

We noticed that if we could count the two buildings together as an unlimited area building per 507.3 Sprinklered, One Story - The area of a Group B, F, M or S building no more than one story above grade plane of any construction type, or the area of a Group A-4 building no more than one story above grade plane of other than Type V construction, shall not be limited where the building is provided with an automatic sprinkler system throughout in accordance with Section 903.3.1.1 and is surrounded and adjoined by public ways or yards not less than 60 feet (18 288 mm) in width.

...but,503.1.2 did not mention section 507, so was that also intentional? Thanks for any advice!

 

[steveray]

Why can't it be one building? Connect it with a roof only....? Which IBC edition?

 

[classicT]

TJ... if you apply Section 507.3 and treat the two buildings as one, you will have no requirement for rated exterior walls per Table 602. I agree that Section 503.1.2 does not mention Section 507, but that would not sway me to say you couldn't apply the provision.

From a fire and life safety point of view, you have provided a greater ability to access the buildings, and egress would typically be shortened or exits increased. This is because with two buildings, your perimeter to area ratio is much higher than in one building with the same area.

 

[TJ_Laccetti]

I believe our best approach is using the unlimited area provision of 507.3 and treating it as one building while actually having 30 feet between the two. I will hang my hat of the provision of 503.1.2 and see if the local building official challenges it. We are currently under the 2018 IBC. Thanks for your thoughts and opinions!