I am working on a small 800 sf T.I. in a two-story office building in New Jersey, converting the space into a dental office. There is an existing toilet room exhaust fan (controlled by switch) that has a duct leading into a cmu shaft that leads to the roof. We are adding an exhaust fan for the lab area (also controlled by a switch) and an exhaust fan in the mechanical closet, controlled by a thermostat.
My mechanical engineer thinks that the two new exhaust fans cannot exhaust into the existing toilet room exhaust duct, but must be separate. IMC 401.4.1 is vague on this - " the exhaust from a bathroom or kitchen in a residential dwelling shall not be considered to be hazardous or noxious contaminant," so my engineer's thinking is that a commercial toilet exhaust would be hazardous.
The DCA official she spoke to said that there is a possibility that if the exhaust systems were combined, there is the possibility that the toilet exhaust could enter the other spaces if the other exhaust fans are 'OFF".
It will be a lot of work to install new exhaust ducts to the roof, and I would like to know if others have run into this situation. Could the exhausts for the two new fans at least be combined?
Thanks, - Donald
My mechanical engineer thinks that the two new exhaust fans cannot exhaust into the existing toilet room exhaust duct, but must be separate. IMC 401.4.1 is vague on this - " the exhaust from a bathroom or kitchen in a residential dwelling shall not be considered to be hazardous or noxious contaminant," so my engineer's thinking is that a commercial toilet exhaust would be hazardous.
The DCA official she spoke to said that there is a possibility that if the exhaust systems were combined, there is the possibility that the toilet exhaust could enter the other spaces if the other exhaust fans are 'OFF".
It will be a lot of work to install new exhaust ducts to the roof, and I would like to know if others have run into this situation. Could the exhausts for the two new fans at least be combined?
Thanks, - Donald