6.3.2.10.Exhaust Ducts and Outlets

(1) Except as provided in Sentence (2), exhaust ducts of non-mechanical ventilating systems serving separate rooms or spaces shall not be combined. (2) Exhaust ducts of non-mechanical ventilating systems serving similar occupancies may be combined immediately below the point of final delivery to the outdoors, such as at the base of a roof ventilator. (3) Exhaust ducts of ventilating systems shall have provision for the removal of condensation where this may be a problem. (4) Exhaust outlets shall be designed to prevent back draft under wind conditions. (5) Except as permitted in Sentence (6), exhaust systems shall discharge directly to the outdoors. (See Note A- 6.3.2.10.(5) and (6)) (6) Exhaust systems are permitted to exhaust into a storage garage, provided (a) they serve rooms that are accessible only from that storage garage, (b) the exhaust contains no contaminants that would adversely affect the air quality in the storage garage, and (See Note A-6.3.2.10.(6)(b)) (c) they are designed in accordance with Sentence 6.3.2.7.(3). (See Note A-6.3.2.10.(5) and (6)) (7) Exhaust ducts connected to laundry drying equipment shall be, (a) independent of other exhaust ducts, (b) designed and installed so that the entire duct can be cleaned, and (c) constructed of smooth corrosion-resistant material. (See Note A-6.3.2.10.(7) and (8)) (8) Where collective venting of multiple installations of laundry-drying equipment is used, the ventilation system shall (a) be connected to a common exhaust duct that is vented by one central exhaust fan, (b) include an interlock to activate the central exhaust fan when laundry-drying equipment is in use, and (c) be provided with make-up air. (See Note A-6.3.2.10.(7) and (8)) (9) Exhaust ducts or vents connected to laundry-drying equipment shall discharge directly to the outdoors. (10) Except as provided in Sentence (12) and except for self-contained systems serving individual dwelling units, exhaust ducts serving rooms containing water closets, urinals, basins, showers or slop sinks shall be independent of other exhaust ducts. (11) Except as provided in Sentence (12) and except for self-contained systems serving individual dwelling units, exhaust ducts serving rooms containing residential cooking equipment shall be independent of other exhaust ducts. (12) Two or more exhaust systems described in Sentences (10) and (11) may be interconnected or connected with exhaust ducts serving other areas of the building, provided (a) the connections are made at the inlet of an exhaust fan, and all interconnected systems are equipped with suitable back pressure devices to prevent the passage of odours from one system to another when the fan is not in operation, or (b) the exhaust ducts discharge to a shaft that is served by an exhaust fan having a capacity that is equal to or greater than the combined capacity of the exhaust fans discharging to the plenum multiplied by the operation diversity factor, provided that the exhaust fan serving the shaft operates continuously. (See Note A-6.3.2.10.(12)(b)) (13) Where exhaust ducts containing air from conditioned spaces pass through or are adjacent to unconditioned spaces, the ducts shall be constructed to prevent condensation from forming on the inside or outside of the ducts. (14) Except as provided in Sentence (15), exhaust air shall be provided at a rate not less than 24 L/s for each water closet, urinal, shower or slop sink. (15) Except as provided in Sentence 6.3.1.1.(4), exhaust air shall be provided for fixtures in dwelling units in accordance with ANSI/ASHRAE 62.1, “Ventilation for Acceptable Indoor Air Quality.” (16) Except for wash basins (lavatories), sanitary facilities in a food premises shall be mechanically ventilated and shall be capable of exhausting air at the rate of not less than 24 L/s for each sanitary fixture listed in Sentence (17). (17) The mechanical ventilation described in Sentence (16) applies to rooms containing water closets, urinals, basins, showers or slop sinks.