Notes to Table 4.1.8.17.:
6.2.3.8. Exhaust Ducts and Outlets (1) Except as provided in Sentence (2), exhaust ducts of nonmechanical ventilating systems serving separate rooms or spaces shall not be combined. (2) Exhaust ducts of nonmechanical ventilating systems serving similar occupancies may be combined immediately below the point of final delivery to the outside, 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. (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 (c) they are designed in accordance with Sentence 6.2.3.9.(3). (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. (8) Except as provided in Sentence (10) 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. (9) Except as provided in Sentence (10) 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. (10) Two or more exhaust systems described in Sentences (8) and (9) 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 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. (11) 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 inside or outside of the ducts. (12) Where an exhaust duct system is used for smoke removal in a high building, the requirements of Article 3.2.6.10. shall apply. (13) Where exhaust duct systems from more than one fire compartment are connected to an exhaust duct in a vertical service space, the requirements of Article 3.6.4.3 shall apply. (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) 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.