Existing building Level 3 remodel, non-separated use

[MattE]

I am doing a code review for a level 3 remodel of an existing non-sprinkled building. The proposed uses are M on the lower level and R-3 on the upper level. Building was originally built in 1951, it is 5500 s.f. on each floor for a total area of 11,000 s.f. Existing building height is 24 feet to the roof. Former use was B on both floors. If I look at Table 508.4, it requires 2-hour fire separation, however I want to see if I can look at it for non-separated occupancies since both uses are below the maximum allowable areas and since the M is on the ground floor it will not exceed the 1 story allowable for that use in a non-sprinkled building.
Codes used locally are the 2018 IEBC and 2018 IBC.

 

[mtlogcabin]

Welcome to the forum

I believe you have a change of use and should be looking at Chapter 10 for your answers. Existing use was a "B" and now you are going to a "M" & R-3 use

1011.1.1 Compliance with Chapter 9.
The requirements of Chapter 9 shall be applicable throughout the building for the new occupancy classification based on the separation conditions set forth in Sections 1011.1.1.1 and 1011.1.1.2.

1011.1.1.1 Change of occupancy classification without separation.
Where a portion of an existing building is changed to a new occupancy classification or where there is a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of the International Building Code, and that portion is not separated from the remainder of the building with fire barriers having a fire-resistance rating as required in the International Building Code for the separate occupancy, the entire building shall comply with all of the requirements of Chapter 9 of this code applied throughout the building for the most restrictive occupancy classification in the building and with the requirements of this chapter.

1011.1.1.2 Change of occupancy classification with separation.
Where a portion of an existing building is changed to a new occupancy classification or where there is a change of occupancy within a space where there is a different fire protection system threshold requirement in Chapter 9 of the International Building Code, and that portion is separated from the remainder of the building with fire barriers having a fire-resistance rating as required in the International Building Code for the separate occupancy, that portion shall comply with all of the requirements of Chapter 9 of this code for the new occupancy classification and with the requirements of this chapter.