Fire dampers for Bathroom exhaust fans

kvarshne

Could any body please let me know if "fire dampers" are required for bathroom exhaust fan mounted on the ROOF. The building is 7 story located in NYC. There is one common shaft which is connected to bathrooms (one on each floor). I really appreciate your help.

PinkTavo

What I have seen in commercial buildings is anywhere ductwork passes thru a fire-rated wall (e.g., apartment into corridor) then fire dampers are required.

Jamie Hall

PinkTavo said:

What I have seen in commercial buildings is anywhere ductwork passes thru a fire-rated wall (e.g., apartment into corridor) then fire dampers are required.

Or ceiling or floor. With firestopping insulation around the duct or pipe.

keyote

http://www2.iccsafe.org/states/newyorkcity/Mechanical/PDFs/Chapter 5_Exhaust Systems.pdf


thats the NYC mech code. 502.10.2 is the section to read.
The answer is no not dryers toilets or residential kitchens. but a back draft damper is best practice on toilet and kitchen but forbidden on dryers. and snow and water considerations need to be addressed.

If your using a mushroom rooftop fans i would mount it on a flashable curb with a BDD size for curb and the fan cfm, the fan supply will have both,If youre on a tight budget just make do with the back draft damper on the fan and use a plumbing vent collar and an inline fan for a 50th of the price, or if youre rich you can get a whole house exhaust system that ties all the toilets and kitchen into one box that adjust speed depending on how many rooms are calling

Answerman

I believe (though I'm not 100% certain) fire dampers are required. On all new construction jobs I work on in NYC, as well as the few ventilation retrofit jobs I've seen, there are fire dampers on all ventilation grilles in apartments that are connected to a central shaft.

I would also strongly recommend CAR (constant air regulator) dampers. These balance the ventilation flow so that you get more or less the same exhaust flow on the upper floors as lower ones. Without these dampers or some other means of balancing, you tend to have more than enough ventilation on upper floors, and too little on the lower floors. You can get a pre-made assembly with car damper and fire damper to make it easier: http://www.aldes.us/airflow-zone-controls/car-fsa-ii

CAR dampers, in conjunction with well-sealed air ducts (especially at the curb/fan connection), and fans using variable speed drive (i.e. Greenheck Vari-green), are the 'best practice' for providing adequate and efficient central ventilation. (unitized ventilation and/or ERVs can be even more efficient, but that's another story..)

keyote

keep in mind commercial and multifamily have different codes from 1-4 family. and ventilation and exhaust or not the same, you are not feeding combustion air to a fire, also penetrating the roof in 1-4 family home is not opening one living space to fire or smoke from another. You dont say what type building but now i notice you are too tall to be a 1-4 family if this is a office building they might require them in the rated shaft enclosing the riser if the roof fan is not connected to the fire command station. But even this will depend on why you are asking. if its an existing building that never had any of that then no worries if you are in a permitted alteration then you may be required to upgrade if the system is being altered. NYC is the most **** code in the world a single job can fall under half a dozen iterations of the code even when you know you are right its often cheaper to do what they want then argue-no the building dept doesnt know what the code means in fact they are least likely to know and usually just tell you to do the most expensive option to cover themselves. same for inexperience architects.