ETThompson
Registered User
Hi
I've looked at several dryer exhaust threads but still not quite clear on the two issues I have on my project. Multifamily apartment/mixed-use, VB, 12.5k sf, full sprinkler. Ohio Building Code 2017, based on 2015 IBC.
1. Can the dryer exhaust penetrate a rated wall? The walls are required to be rated for two reasons, either fire separation distance less than 10' (which means they are 1-hour rated from exterior as well as interior) or because some of them are part of an egress court. I know that the mechanical code (IMC) 504.2 says you cannot unless the duct is constructed of the right material (which we can do) and in compliance with the building code.
IBC 705.10 tells me ducts in exterior FRR walls required to have opening protections shall comply with section 717. But the reference there (717.5.6) is circular, referring back to 705.10. But my reading anyway is I don't have to have opening protectives per 705.8 - we're under the percentage of required openings for that wall. Is that correct?
2. Secondly, we had planned to run our dryer duct through the floor assembly (L528), based on input from our mechanical engineer. We are using a 14" depth, so we can't have dampers anyway (L528 requires 18" depth for using approved dampers). The concept was that since the dryer duct did not (and cannot) have dampers, this should be allowable. The dryer duct starts at a non-rated wall, turns vertically up into it, penetrates the top of the non-rated partition, and turns from vertical to horizontal laterally to head out (in a straight run) to the exterior facade. Am I right in thinking this should work, and without modifying the 14" depth?
Thanks
I've looked at several dryer exhaust threads but still not quite clear on the two issues I have on my project. Multifamily apartment/mixed-use, VB, 12.5k sf, full sprinkler. Ohio Building Code 2017, based on 2015 IBC.
1. Can the dryer exhaust penetrate a rated wall? The walls are required to be rated for two reasons, either fire separation distance less than 10' (which means they are 1-hour rated from exterior as well as interior) or because some of them are part of an egress court. I know that the mechanical code (IMC) 504.2 says you cannot unless the duct is constructed of the right material (which we can do) and in compliance with the building code.
IBC 705.10 tells me ducts in exterior FRR walls required to have opening protections shall comply with section 717. But the reference there (717.5.6) is circular, referring back to 705.10. But my reading anyway is I don't have to have opening protectives per 705.8 - we're under the percentage of required openings for that wall. Is that correct?
2. Secondly, we had planned to run our dryer duct through the floor assembly (L528), based on input from our mechanical engineer. We are using a 14" depth, so we can't have dampers anyway (L528 requires 18" depth for using approved dampers). The concept was that since the dryer duct did not (and cannot) have dampers, this should be allowable. The dryer duct starts at a non-rated wall, turns vertically up into it, penetrates the top of the non-rated partition, and turns from vertical to horizontal laterally to head out (in a straight run) to the exterior facade. Am I right in thinking this should work, and without modifying the 14" depth?
Thanks