partial converting of A-2 into a B occupancy, 2-story

[Morphdesigns]

Existing Construction type: IIIB
Existing Occupancy: A-2, both levels
occupant load first level = 300
occupant load second level = 300 +/-
I am in Wisconsin, and using IBC 2009
1st level sqft = 10,000 +/-
2nd level sqft = 8,000 +/-
ibc table 503 allowable for A-2/IIIB = 9.5k sqft/level
There is an issue with ibc 903.2.1.2, occupancy over 100 and over 5,000 sqft, need to sprinkler. However, since this is an existing occupancy, it is grandfathered in because the original code, when it became an A-2 occupancy, allowed this area/occupancy load without a sprinkler

This has been an A-2 building for many years, both first and second levels were same tenant.

New owner wants to convert a 1500 sqft portion of the first floor into a single tenant B occupancy, with its own entrance. And convert the complete second story into a B occupancy w/ multiple tenants. The entrance will be in back, and will be a shared entrance with the a-2 (first floor), so need a common vestibule.


Couple of issues
1. We are doing a full change-of-use in the second level. Currently no elevators existing to this level. Because this is an existing building, can we get by with a LULA lift platform or does this building need a full-fledge elevator?
2. With the change-of-use in the second level, from a A-2, to a B, I think we need to rate the floor per ibc table 508.4 (required separation of separated occupancies)
3. with a portion change-of-use in the first level, am I correct in guessing that we will need to provide a 2-hour rated wall between the B and A-2 occupancy? Again using IBC table 508.4

Just getting thoughts on this subject. Difficult project to determine.

 

[RLGA]

In this case the IEBC comes into play if the jurisdiction has adopted it. If not, IBC Chapter 34 is applicable. Considering the latter be applicable, IBC Section 3408.1 states that a building undergoing a change is subject to compliance of requirements of the code for the change. If the building complies with the IBC for height and area for Group A-2, Type IIIB construction (i.e., for nonseparated occupancies per IBC Section 508.3), then the conversion of Group A-2 on the 2nd story to Group B doesn't really change the occupancy group of the building. Since the building does not have a sprinkler system, to cover the additional 500 sq. ft. on the 1st story (10,000 sq. ft. actual - 9,500 sq. ft. per Table 503 = 500 sq. ft.) you will have to consider a frontage increase. If that is not an option, then separation of occupancies will be required per IBC Section 508.4, and a 2-hour fire barrier and horizontal assembly will be required.

Further in IBC Section 3408.1 it states that compliance with all of the requirements of the IBC may not be required if determined that the new occupancy is less hazardous than the existing use, subject to approval of the building official.

If the Group A-2 on the 1st story is not being altered, then a sprinkler system would not be required, since areas unaffected by the new work are not subject to the current code. If the 1st story is altered, it is still unlikely that a sprinkler system will be required unless the Group A-2 increases in floor area and/or occupant load. IBC Section 3404.1 states that alterations cannot make a building less compliant, and by adding floor area and/or occupant load to the Group A-2 would make the building less compliant and a sprinkler system would then be required.