can bathroom exhaust be interchanged with each other
can bathroom exhaust be interchanged with each other
(OP)
I have a 44 apartment complex that all baths were vented to the attic (1972). Code is telling me I have to vent outside. I am well aware of grandfather laws but want to comply. Only question is can I hook 10 exhaust to 1 duct going out through roof so I dont have 80 holes in roof?





RE: can bathroom exhaust be interchanged with each other
RE: can bathroom exhaust be interchanged with each other
RE: can bathroom exhaust be interchanged with each other
EEJaime said he didn't know if it was a code issue or not -- but I agree with him, when one fan isn't on (or one fan fails), the others can dump exhaust air backward through the non-working fan into the occupied space. Backdraft dampers to prevent this add complexity and energy to the mix. I prefer one big fan and one big backdraft damper, but that's just my opinion.
Good on ya!
Goober Dave
RE: can bathroom exhaust be interchanged with each other
Crosstalk in the duct between bathrooms will be a problem and what happens to duct pressure as fans are turned on/off? What happens when a backdraft damper hangs up? What about fire penetrations from different occupancies?
Don't do it.
RE: can bathroom exhaust be interchanged with each other
As I stated in my post, that I did not know if it was a code issue. I stated that it should be, because interconnecting multiple ceiling fans is a very bad idea. Exhausting toilet room air into a duct that can enter an adjacent occupancy is not only bad engineering, it is downright rude. Just a common sense approach.
EEJaime
RE: can bathroom exhaust be interchanged with each other
RE: can bathroom exhaust be interchanged with each other
RE: can bathroom exhaust be interchanged with each other
RE: can bathroom exhaust be interchanged with each other
I would inspect the ceiling mounted exhaust fans. The fans may not have back draft dampers or the dampers may be inoperable. A 1972 ceiling fan is at the end of its service life. Broan / Nutone sold tons of axial prop fans in the 70s. Theses fans just made noise and did not move air. The duct condition should also be assessed. The duct may require cleaning. I am assuming this is a multistory building (3-4 stories). We normally combine the ducting in the attic space into one roof vent above a group of fans. Minimize the lateral distance the fan must push the air in the horizontal distance. We do not use plenum dividers inside the roof vent. Adding duct work and a vent hood will add resistance to the fan. You do not complaints from people that the fans to not work after modifications (they may never have vented correctly).
A change in venting may cause an issue with the fire rating of your assemblies. Codes have changed drastically since 1972. Be very careful about shafting and the rating of the units. Various manufactures make a fire damper that fits the inlet grille.
Check the flow rating of the fans. Old applications may have required only 35 CFM per washroom. You should be in the range of 75 to 100 CFM per washroom. I prefer to use a Panasonic or Broan fan. http://www
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RE: can bathroom exhaust be interchanged with each other
Paul G.