The Ontario Building Code | Supplemental Exhaust
9.32.3.5. Supplemental Exhaust
(1) Additional supplemental exhaust capacity shall be installed as necessary so that the total capacity of all kitchen, bathroom, water closet room and other supplemental exhaust air intakes is not less than the total ventilation capacity, as required in Article 9.32.3.3., minus the principal exhaust fan capacity, as required in Article 9.32.3.4.
(2) An exhaust air intake shall be installed in each kitchen, bathroom and water closet room.
(3) Where the intake for a supplemental exhaust fan, other than a cooking appliance exhaust fan serving a cooktop, is installed in a kitchen, it shall be installed in the ceiling or on the wall within 300 mm of the ceiling.
(4) Exhaust ducts serving the required kitchen, bathroom, water closet room and other supplemental exhaust air intakes shall be sized according to Part 6 except that they may be sized according to Table 9.32.3.5. where,
(a) the total duct length does not exceed 9 m, and
(b) the number of elbows does not exceed 4,
but, in any case, they shall not be smaller than recommended by the manufacturer of the fans.
Table 9.32.3.5.
Kitchen, Bathroom and water Closet Room Exhaust Duct Size
Forming Part of Sentence 9.32.3.5.(4)
| Item | Column 1 | Column 2 | Column 3 |
|
| Fan Capacity, L/s | Minimum Exhaust Duct Diameter(1) |
|
|
|
| Ducts Connected to Inlet and outlet of Exhaust Fan, mm | Ducts Connected to One Side Only of Exhaust Fan, mm |
| 1. | 25 | 125 | 125 |
| 2. | 50 | 150 | 150 |
Notes to Table 9.32.3.5.:
(1) Where flexible duct is used, the duct diameter shall be increased by 25 mm.
(5) A supplemental exhaust fan required by this Article shall be controlled by a manual switch located in the room served by the exhaust fan.
(6) Where the supplemental exhaust is provided by an exhaust fan serving multiple exhaust air intakes required in rooms described in Sentence (2), the exhaust fan shall be controlled by a manual switch located in each room served by that exhaust fan and wireref ="http://thehandyforce.com/electrical/" title ="Electricians in East York">wired in parallel.
(7) Where the supplemental exhaust is provided by a principal exhaust fan serving multiple exhaust air intakes required in rooms described in Sentence (2), the principal exhaust fan shall be controlled by a manual switch located in each room served by that exhaust fan and wireref ="http://thehandyforce.com/electrical/" title ="Electricians in East York">wired in parallel with the manual switch required in Sentence 9.32.3.4.(4).
(8) Where a supplemental fan required by this Article is controlled by a dehumidistat or other automatic control device in addition to the manual switch required by Sentences (5) to (7), the manual switch shall be capable of activating the fan regardless of the setting of the automatic control.
(9) Supplemental exhaust required in this Article may be provided by means of a heat recovery ventilator installed in accordance with Article 9.32.3.11.