Apartment exhaust and rated ceilings

[Toastie]

I have some low rise apartments that have the typical exhaust: dryer, bathroom, and kitchen. The apartments also has a rated ceiling with a drop ceiling so the supply duct does not have to penetrate the rated ceiling. However the exhaust does need to penetrate it, and the exits the building horizontally without ever leaving that apartment unit. I know dryers do not require dampers (per IMC). The question I have is where does it say the bathroom and kitchen exhaust does not need to have a damper on them? Is it because the ducts are within the individual apartment space from when it starts to the exterior wall?

 

[nuuvox000]

I've done a few of these designs and I believe the bathroom and kitchen exhaust DO require dampers. Usually the fan is installed in the rated ceiling so it needs an integral ceiling radiation damper. In your case, I think you'll need a fire damper (don't forget an access door). Interestingly, our local inspectors consider recirculating fans over a stove as kitchen exhaust so we don't have to run those outdoors.