Hi everyone, I have a question about the IBC Table 508.4 (any recent version) which is the separation requirements for mixed use occupancies.
When a mixed use occupancy has a B and an S-1, there is no separation requirement between the two types. However, a mixed use B and S-2 has a 1 or 2 hour separation requirement, depending on sprinklers.
My question is why the code requires more restrictive construction for a lesser hazard occupancy type. S-1 materials are identified as moderate hazard as they more readily support combustion as opposed to the low hazard materials in S-2. I would think that the requirement for a 1 or 2 hour separation would be on the B/S-1 mix, not the B/S-2.
I am going to read through the IBC commentary tomorrow at work, but I was curious if any of you have ran across this before and can explain the intent because I know I'm missing something.
Thank you!
When a mixed use occupancy has a B and an S-1, there is no separation requirement between the two types. However, a mixed use B and S-2 has a 1 or 2 hour separation requirement, depending on sprinklers.
My question is why the code requires more restrictive construction for a lesser hazard occupancy type. S-1 materials are identified as moderate hazard as they more readily support combustion as opposed to the low hazard materials in S-2. I would think that the requirement for a 1 or 2 hour separation would be on the B/S-1 mix, not the B/S-2.
I am going to read through the IBC commentary tomorrow at work, but I was curious if any of you have ran across this before and can explain the intent because I know I'm missing something.
Thank you!
