9.32.3.13.Outdoor Intake and Exhaust Openings

(1) Intake openings shall be located so as to avoid contamination of the ventilation air from other local sources such as automobile exhaust and exhaust from the building or adjacent buildings. (2) The distance from the bottom of an air intake opening to finished ground or to any nearer and lower permanent horizontal surface shall be not less than 450 mm or the depth of expected snow accumulation, whichever is greater. (3) The distance separating air intakes for mechanical ventilation from exhaust outlets that are potential sources of contaminants, such as gas vents or oil fill pipes, shall be not less than 1 800 mm. (4) Except as provided in Sentences (5) and (6), exhaust outlets that discharge air containing moisture, such as bathroom ventilation and clothes dryer exhaust outlets, shall be located at least 1 800 mm from air intakes and vented soffits. (5) Where an exhaust outlet referred to in Sentence (4) is located within a soffit, the soffit shall either be unvented, or if vented, the full depth of the soffit shall be blocked for a distance of 1 800 mm on each side of the exhaust outlet. (6) Where an exhaust outlet referred to in Sentence (4) is located in a side wall less than 1 800 mm from a soffit, a section of the soffit above the exhaust outlet shall be unvented, or if vented, the full depth of the soffit shall be blocked in accordance with the widths stipulated in Table 9.32.3.13.-A, centred over the location of the outlet. Table 9.32.3.13.-A Widths of Unvented or Blocked Soffits Where Exhaust Outlets Are Less Than 1 800 mm from a Soffit Forming Part of Sentence 9.32.3.13.(6) Total Width of Unvented or Blocked Soffit Centred Distance Between Exhaust Outlet and Soffit, mm Over Location of Exhaust Outlet, mm 1 to 300 3 600 301 to 600 3 400 601 to 900 3 100 901 to 1 200 2 700 1 201 to 1 500 2 000 1 501 to 1 799 1 000 (7) Air intakes shall be clearly labeled as such for identification from locations outside the dwelling unit. (8) The distance from the bottom of an exhaust outlet to finished ground or to any nearer and lower permanent horizontal surface shall be not less than 100 mm. (9) Where air intake and exhaust openings are in exposed locations, provision shall be made to protect them from the entry of precipitation by the use of louvres, weather cowls or other suitable protection. (10) Air intake openings shall incorporate screens or grilles to protect against the entry of animals and insects. (11) Except for exhaust outlets serving heat recovery ventilators, exhaust outlets shall incorporate backdraft dampers. (12) An exhaust outlet that does not incorporate a backdraft damper located at the building envelope shall incorporate a screen located at the building envelope to protect against the entry of animals. (13) Screens, grilles and filters installed in air intake and exhaust openings shall be easily removable for cleaning purposes, without the need for special tools. (14) Where screens or grilles are installed in air intake and exhaust openings, the net free area of the air intake or exhaust opening shall be equal to or greater than the required cross-sectional area of the duct served or such openings shall comply with Table 9.32.3.13.-B. (15) Screens and grilles shall be of corrosion-resistant material. Table 9.32.3.13.-B Area of Openings with Screens or Grilles Forming Part of Sentence 9.32.3.13.(14) Mesh Size of Screen or Grille, mm Area of Opening Less than 4 3 times required area of duct served 4 to 6 2 times required area of duct served Larger than 6 Required area of duct served