The Ontario Building Code | Fans and Associated Air Handling Equipment
22.214.171.124. Fans and Associated Air Handling Equipment
(1) Fans for heating, ventilating and air-conditioningsystems shall be located and installed so that their operation,
(a) does not adversely affect the draft required for proper operation of fuel-fired appliances, and
(b) does not allow the air in the air duct system to be contaminated by air or gases from the boiler-room or furnace-room.
(2) Fans and associated air handling equipment, such as air washers, filters and heating and cooling units, when installed on the roof or elsewhere outside the building, shall be of a type designed for outdoorref ="http://thehandyforce.com/doors/" title ="Toronto Door installer">door use.