As many of you are probably familiar with, for years, when designing a building such as an office that has a storage room that is greater than 100 square feet in area, and is identified as “storage,” we needed to provide a 1 hour fire barrier separation around the storage room in non-sprinklered buildings. If the building was sprinklered, the wall didn’t need to be fire-rated, but was still required to be resistant to the passage of smoke. The creative solution that was often used for non-sprinklered storage rooms was to carefully design the room so that it was 99 square feet or less. How many times did you do that?
With the 2011 Ohio Building Code (2009), this section has now changed. When you go to Table 508.2.5 Incidental Accessory Occupancies, you will note that “storage” rooms have now disappeared from this table.
Was this a type-o or mistake in publishing? No, it was a deliberate change made through the code hearing process and voted upon by the International Code Council.
The reason for this change is as follows: Storage rooms are no longer considered as incidental accessory use. Instead, areas used for storage are to be considered as either accessory use, or a distinct occupancy unto itself.
If considered as accessory, it must meet the requirements of Section 508.2.1, which requires that the accessory occupancy not occupy more than a 10% limitation noted above. The 2nd option would be to consider the building then as a mixed use, with storage being one of those uses. If mixed use, the designer can then explore the options for mixed use, whether to utilize non-separated mixed use under the requirements of Section 508.3, or to treat as separated occupancies per Section 508.4, which requires a rated fire barrier to occur between the mixed uses.
So, for the example of the small storage room that occurs within an office that was first indicated, having a fire rating around such a room is no longer required unless it exceeds 10% of the area of the main use.
original article : http://www.ma-architects.com/fire-barrier-separation/