We have an existing 3 story building that is currently classified as an R-2. We will be converting it into an R-3/B with the B separated by a 2-hr rated assembly, right now we are only dealing with the R-3 portion. There will be 2 dwellings in the R-3, one on the 1st and 2nd floor, and one on the 3rd floor. There is an exit access stairway that provides egress for the 3rd floor tenant as well as the 2nd and 1st floors. There are two means of egress for both dwellings, the 3rd floor also has a fire escape.
The exit access stairway walls and also 2nd floor ceiling have been gutted. We have new ductwork installed on the 2nd floor and supplies that penetrate the ceiling assembly and a return that goes through the exit access stairway. We are trying to avoid having to rework the ductwork if possible. Adding smoke dampers to the supplies penetrating the 2nd floor ceiling to achieve the 1-hr horizontal separation between dwellings doesn't seem to be that big of a deal. Getting the exit access stairway up to 1-hr rating based on the IBC seems to be a lot harder. We don't mind installing a sprinkler system and would actually prefer that over adding a manual fire alarm, rated assemblies, etc since a sprinkler we think would be safer. We would like to use either the work area compliance method or performance compliance method to satisfy the required code.
Work Area Compliance Method
If we go this route we would need to install a 13-D sprinkler, provide egress lighting / exit signs, follow everything in Chapters 10, 9, 8, 7. Since the R-3 is a lower hazard category than the R-2 it doesn't appear there needs to be any changes done to the egress (rated walls, etc) other than make the exit access stairway smoke tight.
The issue I see us running into is this part of the code
Would we have to meet the IBC requirements and provide a rated assembly on the 2nd floor ceiling to separate the dwelling units and a rated enclosure to the exit stairway since the walls / ceiling were removed?
Performance Compliance Method
If we went this route with a 13-D sprinkler I believe we could get by without having to do the rated separations between the dwellings, but would definitely have to have 1-hr rated vertical openings to get the points needed. Would the exit access stairway have to satisfy all the requirements of a 1-hr rating exit access stairway in the IBC?
The exit access stairway walls and also 2nd floor ceiling have been gutted. We have new ductwork installed on the 2nd floor and supplies that penetrate the ceiling assembly and a return that goes through the exit access stairway. We are trying to avoid having to rework the ductwork if possible. Adding smoke dampers to the supplies penetrating the 2nd floor ceiling to achieve the 1-hr horizontal separation between dwellings doesn't seem to be that big of a deal. Getting the exit access stairway up to 1-hr rating based on the IBC seems to be a lot harder. We don't mind installing a sprinkler system and would actually prefer that over adding a manual fire alarm, rated assemblies, etc since a sprinkler we think would be safer. We would like to use either the work area compliance method or performance compliance method to satisfy the required code.
Work Area Compliance Method
If we go this route we would need to install a 13-D sprinkler, provide egress lighting / exit signs, follow everything in Chapters 10, 9, 8, 7. Since the R-3 is a lower hazard category than the R-2 it doesn't appear there needs to be any changes done to the egress (rated walls, etc) other than make the exit access stairway smoke tight.
The issue I see us running into is this part of the code
801.3 Compliance
All new construction elements, components, systems, and spaces shall comply with the requirements of the International Building Code.
All new construction elements, components, systems, and spaces shall comply with the requirements of the International Building Code.
Would we have to meet the IBC requirements and provide a rated assembly on the 2nd floor ceiling to separate the dwelling units and a rated enclosure to the exit stairway since the walls / ceiling were removed?
Performance Compliance Method
If we went this route with a 13-D sprinkler I believe we could get by without having to do the rated separations between the dwellings, but would definitely have to have 1-hr rated vertical openings to get the points needed. Would the exit access stairway have to satisfy all the requirements of a 1-hr rating exit access stairway in the IBC?