Mechanical ventilation systems complying with the balance of this Subsection shall incorporate at least the following components:
a principal ventilation system complying with Article 9.32.3.3.,
supplemental exhaust fans complying with Article 9.32.3.7., and
protection against depressurization in accordance with Article 9.32.3.8.
9.32.3.2.
Design and Installation
Aspects of mechanical ventilation systems not specifically described in this Subsection shall be designed, constructed and installed in accordance with good practice such as that described in the ASHRAE Handbooks and Standards, the HRAI Digest, the HRAI Residential Mechanical Ventilation Manual, the Hydronics Institute Manuals and the SMACNA manuals.
Ventilation system equipment installed to meet the requirements of this Section shall be installed in accordance with the manufacturers' instructions and recommendations except that, where such instructions and recommendations are in conflict with the requirements of this Subsection, the requirements of this Subsection shall govern.
Except where mounted on concrete foundations, fans and heat recovery ventilators shall be isolated from structural components by resilient mountings to minimize the transmission of noise and vibration to occupied spaces.
Where flow-regulating dampers are required,
they shall be adjustable and accessible without requiring the removal of fans, motors or insulating materials, or the use of specialized tools, and
a device on the outside of the duct or device in which they are installed shall indicate the position of the damper.
Ventilation equipment shall be accessible for inspection, maintenance, repair and cleaning.
Ventilation equipment installed in unheated spaces shall be installed so as to avoid condensation of moisture on fans and motors, in accordance with the manufacturers' instructions.
The principal ventilation system shall incorporate the following components:
a principal ventilation fan complying with this Article, and
except as permitted by Article 9.32.3.6., provision for the introduction of outdoor air to the dwelling unit, in conformance with Article 9.32.3.4. or 9.32.3.5.
The principal ventilation fan shall be capable of operating at an exhaust capacity complying with Table 9.32.3.3., referred to hereinafter as the "normal operating exhaust capacity." (See Note A-9.32.3.3.(2).)
Table 9.32.3.3.
Normal Operating Exhaust Capacity of Principal Ventilation Fan
Forming Part of Sentence 9.32.3.3.(2)
The requirement for a principal ventilation fan may be satisfied by a single fan, by the exhaust side of a heat recovery ventilator, or by a group of fans, provided all fans in the group are controlled simultaneously by a controller complying with Sentences (5), (6) and (7). (See Note A-9.32.3.3.(3).)
The components of the principal ventilation system shall be approved by their manufacturer for continuous operation.
The principal ventilation fan shall be controlled by a manual switch located within the living area of the dwelling unit and clearly marked "VENTILATION FAN." (See Note A-9.32.3.3.(5).)
If all controls serving the principal ventilation fan are in the "off" position, the principal ventilation system shall not operate.
The requirement for a manual switch stated in Sentence (5) can be satisfied by a manual override incorporated in a dehumidistat or other automatic control, provided
the automatic control is located within the living area of the dwelling unit, and
the manual override is clearly marked "VENTILATION FAN."
Where the principal ventilation fan is controlled by a dehumidistat or other automatic control in addition to the manual switch required by Sentence (5), the manual switch shall be capable of activating the fan regardless of the setting of the automatic control.
Where an exhaust air intake for the principal ventilation fan is connected directly to the return side of the duct system of a forced air heating system or other forced air distribution system, it shall be connected, where applicable, not less than 1 m upstream from the connection of the outdoor air supply duct required by Sentence 9.32.3.4.(5).
Exhaust air intakes for principal ventilation fans located in kitchens, bathrooms and water-closet rooms shall be located in the ceiling or on the wall not less than 2 m above the floor. (See Note A-9.32.3.3.(10).)
9.32.3.4.
Ventilation Systems Used in Conjunction with Forced Air Heating Systems
(See Note A-9.32.3.4.)
Where outdoor air is to be introduced to the dwelling unit through a forced air heating system, the provision of outdoor air shall comply with this Article.
Where the actual normal operating exhaust capacity of the fan installed to satisfy the requirement for a principal ventilation fan exceeds the maximum outdoor airflow permitted by Table 9.32.3.4. for a mixed air temperature of 15°C or exceeds the minimum acceptable return air temperature specified by the manufacturer of the furnace, whichever is less, then either
the system shall incorporate a means for tempering outdoor air introduced to the heating system ducts so that a mixed air temperature of 15°C or the minimum acceptable return air temperature specified by the manufacturer of the furnace, whichever is less, is achieved when the outdoor air is at the January 2.5% temperature and the indoor air temperature is 22°C, or
this Article shall be considered to be no longer applicable and the mechanical ventilation system shall comply with either Clause 9.32.3.1.(1)(a) or with Article 9.32.3.5.
For the purposes of Table 9.32.3.4., the furnace airflow shall be determined
by operating the forced air heating system's circulation fan at the rate chosen to satisfy Clause (9)(a) when measuring the return airflow in the furnace return air plenum immediately upstream of the connection of the outdoor air supply duct required by Sentence (5) and then adding this return airflow measurement to the actual normal operating exhaust capacity of the fan installed to satisfy the requirement for a principal ventilation fan, or
by using the manufacturer's rated flow for the furnace for 150 Pa static pressure and the wiring configuration necessary to achieve the flow specified in Clause (9)(a).
Linear interpolation is permitted in using Table 9.32.3.4.
Table 9.32.3.4.
Maximum Outdoor Airflow
Forming Part of Sentence 9.32.3.4.(2)
An outdoor air supply duct shall be installed between the outdoors and the furnace return air plenum and shall be connected
not less than 3 m upstream of the plenum connection to the furnace, as measured along the length of the duct, or
through an acceptable mixing device installed in the return air plenum.
The outdoor air supply duct required by Sentence (5) shall incorporate a flow-regulating damper.
Where the outdoor air supply duct required by Sentence (5) is not connected to an outdoor air supply fan, it shall be connected downstream of all return branch connections.
Where the outdoor air supply duct required by Sentence (5) is connected to an auxiliary outdoor air supply fan, the auxiliary outdoor air supply fan shall be
approved by the manufacturer for the handling of untempered outdoor air if it will be handling untempered outdoor air,
approved by the manufacturer for continuous operation, and
designed to provide an outdoor air supply flow within ±10% of the actual normal operating exhaust capacity of the exhaust fan installed to satisfy the requirement for a principal ventilation fan.
The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that
activation of the principal ventilation fan automatically activates the forced air heating system's circulation fan to provide an airflow not greater than the space-heating airflow,
where applicable, activation of the principal ventilation fan automatically activates the auxiliary outdoor air supply fan described in Sentence (8), and
the auxiliary outdoor air supply fan does not operate when the principal ventilation fan is not operating.
With the principal ventilation fan operating at its normal operating exhaust capacity, the airflow in the outdoor air supply duct shall be measured and the flow-regulating damper required by Sentence (6) shall be adjusted and permanently fixed so that the airflow in the outdoor air supply duct is within ±10% of the actual normal operating exhaust capacity of the principal ventilation fan.
The airflow measurements required by Sentences (3) and (10) shall be done using a method accurate to within ±15% of the flow rate being measured.
All connections between the ventilation system and the heating system shall be in accordance with Articles 9.33.4.1. and 9.33.5.2.
9.32.3.5.
Ventilation Systems Not Used in Conjunction with Forced Air Heating Systems (See Note A-9.32.3.5.)
Where outdoor air is to be introduced to the dwelling unit through means other than a forced air heating system, the provision of outdoor air shall comply with this Article.
An outdoor air supply fan shall be installed with a rated capacity within ±10% of the actual normal operating exhaust capacity of the exhaust fan installed to satisfy the requirement for a principal ventilation fan.
The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that
activation of the principal ventilation fan automatically activates the outdoor air supply fan required by Sentence (2), and
the outdoor air supply fan does not operate when the principal ventilation fan is not operating.
The outdoor air supply fan shall be connected to the outdoors through an outdoor air supply duct.
The outdoor air supply duct required by Sentence (4) shall incorporate a flow-regulating damper.
With the principal ventilation fan operating at its normal operating exhaust capacity, the airflow in the outdoor air supply duct shall be measured and the flow-regulating damper required by Sentence (5) shall be adjusted and permanently fixed so that the airflow in the outdoor air supply duct is within ±10% of the actual normal operating exhaust capacity of the principal ventilation fan.
The airflow measurements required by Sentence (6) shall be done using a method accurate to within ±15% of the flow rate being measured.
Except where a heat recovery ventilator is used to supply the outdoor air, the outdoor air shall be tempered to at least 12°C before being circulated to habitable spaces.
Any tempering device installed to comply with Sentence (8) shall be installed in accordance with Articles 9.33.4.1. and 9.33.5.2.
Except as provided in Sentence (11), outdoor air shall be distributed by a system of trunk and branch supply ducts, from the outdoor air supply fan required by Sentence (2) to
each bedroom,
any storey, including basements and heated crawl spaces, without a bedroom, and
if there is no storey without a bedroom, to the principal living area.
In a dwelling unit in which there is no storey without a bedroom, if an exhaust air intake for the principal ventilation fan is located in the principal living area and the principal ventilation fan has no more than 2 exhaust air intakes located in other rooms, distribution of outdoor air to the principal living area is not required.
All branch supply ducts that are not fitted with diffusers with adjustable balance stops shall be supplied with balancing dampers that
can be fixed in their adjusted positions, and
include devices to indicate the positions of the dampers.
The air supply outlets through which outdoor air is delivered to the rooms shall be located in the ceiling or in a wall at not less than 2 m above the floor and shall be designed and installed to promote diffusion across the ceiling.
Provision shall be made for the free flow of air to or from all rooms by leaving gaps beneath doors, using louvred doors or installing grilles in doors.
9.32.3.6.
Exhaust-Only Ventilation Systems (See Note A-9.32.3.6.)
A ventilation system with no provision for the introduction of outdoor air to the dwelling unit may only be used where the dwelling unit
contains no solid-fuel-burning appliance, no fireplace of other than direct-vented type, and no other fuel-fired space- or water-heating appliance of other than direct-vented or mechanically vented types, and
has a forced air distribution system with a circulation fan with a rated capacity equal to at least 5 times the actual normal operating exhaust capacity of the fan installed to satisfy the requirement for a principal ventilation fan, a supply side that complies with Sentences 9.32.3.5.(10) to (12), and a return side that complies with Articles 9.33.6.12. and 9.33.6.13.
Except as provided in Sentence (3), where an exhaust-only system is installed, the principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that, where applicable, activation of the principal ventilation fan automatically activates the circulation fan of the forced air distribution system required by Clause (1)(b) at its rated capacity.
Interlocking the forced air distribution system's circulation fan with the principal ventilation fan as required by Sentence (2) is not required where the forced air distribution system is equipped with a control that automatically activates the circulation fan at user-selected intervals.
Except as provided in Sentences (2) and (3), a supplemental exhaust fan with a rated capacity not less than 50 L/s shall be installed in each kitchen.
A supplemental exhaust fan is not required in a kitchen where the only exhaust air intake for the principal ventilation fan is located in that kitchen.
A supplemental exhaust fan is not required in a kitchen where the principal ventilation fan draws from that kitchen and other rooms, provided
the principal ventilation fan can be switched to a high exhaust rate equal to not less than 2.5 times the minimum normal operating exhaust capacity specified in Table 9.32.3.3., and
the high exhaust rate of the principal ventilation fan, as described in Clause (a), is activated by a manual switch in the kitchen labeled "KITCHEN EXHAUST."
Where an exhaust air intake for the principal ventilation fan is not located in a bathroom or water-closet room, a supplemental exhaust fan with a rated capacity not less than 25 L/s shall be installed in that bathroom or water-closet room.
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 at not less than 2 m above the floor.
A supplemental exhaust fan required by this Article shall be controlled by a manual switch located in the room served by the fan.
Where a kitchen or bathroom is exempted from the requirement to install a supplemental exhaust fan by virtue of Sentences (2) or (3), the principal ventilation fan shall be controlled by a manual switch located in the kitchen or bathroom and wired in parallel with the manual switch required by Sentence 9.32.3.3.(5).
Where a supplemental exhaust fan required by this Article is controlled by a dehumidistat or other automatic control in addition to the manual switch required by Sentence (6), the manual switch shall be capable of activating the fan regardless of the setting of the automatic control.
dwelling units that contain a fuel-fired space-heating appliance or fuel-fired water-heating appliance of other than direct-vented or mechanically vented types, and
ancillary spaces that contain an exhaust device, where the space is not within a dwelling unit in a house with a secondary suite and where the house with a secondary suite contains a fuel-fired space-heating appliance or fuel-fired water-heating appliance of other than direct-vented or mechanically vented types.
Except as provided in Sentences (6) to (8), any mechanical air exhausting device, other than the principal ventilation fan operating at a rate not greater than the maximum permitted by Table 9.32.3.3., shall be provided with outdoor makeup air supplied by a fan rated to deliver outdoor air to the dwelling unit at a rate
not less than the exhaust capacity of the device, and
not greater than that exhaust capacity plus 10%.
An outdoor makeup air supply fan required by Sentence (2) shall be wired so that it is activated whenever the device for which it supplies outdoor makeup air is activated.
The outdoor makeup air required by Sentence (2) shall be
introduced to a normally unoccupied area in the dwelling unit, or
tempered to at least 12°C before being introduced to occupied areas or to a supply duct system.
If the outdoor makeup air required by Sentence (2) is not tempered upstream of the supply fan, the supply fan required by Sentence (2) shall be approved by the manufacturer for the handling of untempered outdoor air.
The provision of makeup air as described in Sentence (2) is not required in a dwelling unit with solid-fuel-burning appliances, where all other fuel-fired appliances are direct-vented or mechanically vented.
The provision of makeup air as described in Sentence (2) is not required if it can be shown using the test procedures in CAN/CGSB-51.71, "Depressurization Test," that the maximum depressurization levels to which fuel-fired space- or water-heating appliances and their venting systems will be exposed will not exceed the limits set out in CAN/CGSB-51.71 for the categories of fuel-fired appliances and venting systems installed in the dwelling unit.
The provision of makeup air as described in Sentence (2) is not required for mechanical exhausting devices operating a subfloor depressurization system installed for the purpose of reducing the risk of radon ingress.
This Article applies to every building that contains a residential occupancy and that also contains
a fuel-burning appliance, or
a storage garage.
Carbon monoxide (CO) alarms required by this Article shall
conform to CAN/CSA-6.19, "Residential Carbon Monoxide Alarming Devices,"
be equipped with an integral alarm that satisfies the audibility requirements of CAN/CSA-6.19, "Residential Carbon Monoxide Alarming Devices,"
have no disconnect switch between the overcurrent device and the CO alarm, where the CO alarm is powered by the dwelling unit's electrical system, and
be mechanically fixed at a height recommended by the manufacturer.
Where a room contains a solid-fuel-burning appliance, a CO alarm conforming to CAN/CSA-6.19, "Residential Carbon Monoxide Alarming Devices," shall be mechanically fixed
at the manufacturer's recommended height where these instructions specifically mention solid-fuel-burning appliances, or
in the absence of specific instructions related to solid-fuel-burning appliances, on or near the ceiling.
Where a fuel-burning appliance is installed in a suite of residential occupancy, a CO alarm shall be installed
inside each bedroom, or
outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.
Where a fuel-burning appliance is installed in a service room that is not in a suite of residential occupancy, a CO alarm shall be installed
either inside each bedroom, or if outside, within 5 m of each bedroom door, measured following corridors and doorways, in every suite of residential occupancy that shares a wall or floor/ceiling assembly with the service room, and
in the service room.
For each suite of residential occupancy that shares a wall or floor/ceiling assembly with a storage garage or that is adjacent to an attic or crawl space to which the storage garage is also adjacent, a CO alarm shall be installed
inside each bedroom, or
outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.
Where CO alarms are installed in a house with a secondary suite including their common spaces, the CO alarms shall be wired so that the activation of any one CO alarm causes all CO alarms within the house with a secondary suite including their common spaces to sound.
Except as provided in Sentence (4), capacity ratings for required fans shall be determined in accordance with
CAN/CSA-C260-M, "Rating the Performance of Residential Mechanical Ventilating Equipment," or
HVI Publication 916, "Airflow Test Procedure."
Sound ratings for fans shall be determined in accordance with
CAN/CSA-C260-M, "Rating the Performance of Residential Mechanical Ventilating Equipment," or
HVI Publication 915, "Loudness Testing and Rating Procedure."
Capacity ratings for fans shall be measured at the external static pressure differentials shown in Table 9.32.3.10.-A.
Fans in heat recovery ventilators used to provide one or more required fans shall have their airflow at normal temperature rated in accordance with CAN/CSA-C439, "Rating the Performance of Heat/Energy-Recovery Ventilators."
Where a heat recovery ventilator is used to provide one or more required fans, it shall have a low-temperature ventilation reduction factor of not less than 50% when tested in accordance with CAN/CSA-C439, "Rating the Performance of Heat/Energy-Recovery Ventilators," at an outdoor temperature at least as low as the outdoor design temperature for the location where the ventilation system is to be installed, but the outdoor design temperature need not be lower than -25°C.
Table 9.32.3.10.-A
Minimum External Static Pressure Differential for Rating of Fans
Forming Part of Sentence 9.32.3.10.(3)
Fans, including makeup air supply fans, installed to satisfy Articles 9.32.3.3. to 9.32.3.8. with less than 1 m of duct between themselves and the visible interior surfaces of rooms other than unfinished basements, furnace rooms, utility rooms and attics, shall have a sound rating complying with Table 9.32.3.10.-B when operating at the required flow rate.
Mechanical ventilation devices shall conform to CSA C22.2 No. 113, "Fans and Ventilators."
Table 9.32.3.10.-B
Maximum Sound Rating for Fans
Forming Part of Sentence 9.32.3.10.(6)
Except as provided in Sentence (6), ventilation ducts and their fittings shall conform to the requirements of Article 9.33.6.2., except that exhaust ducts serving only a bathroom or water-closet room are permitted to be of combustible material, provided they are reasonably airtight and constructed of a material impervious to water.
Exhaust ducts shall not discharge into heated or unheated enclosed spaces.
Where an exhaust duct passes through an unheated space or is not separated from an unheated space by an insulated building assembly, the duct shall be insulated to not less than RSI 0.5.
Where a duct carrying outdoor air that is not tempered and not mixed with indoor air passes through heated space, it shall be
insulated to not less than RSI 0.5, and
provided with a vapour barrier.
All exhaust intakes located within 3 m horizontally of a cooktop shall be equipped with a grease filter at the intake end.
Ductwork for cooking appliance exhaust fans shall
be of noncombustible, corrosion-resistant material,
lead directly to the outdoors with no connections to other exhaust fans or ducts, and
be equipped with a grease filter at the intake end.
All ductwork shall be installed to avoid crushing and shall be permanently supported to prevent sagging.
Joints in all ventilation system ducting shall be sealed with mastic, metal foil duct tape or the manufacturers' specified sealants.
Except where the size of a duct can be determined using Table 9.32.3.11.-A or Table 9.32.3.11.-B, duct sizes shall be determined according to Subsection 9.33.4.
Table 9.32.3.11.-A
Equivalent Duct Sizes
Forming Part of Sentence 9.32.3.11.(9)
In using Table 9.32.3.11.-A,
when sizing branch ducts, "maximum length of duct" refers to the physical length of the duct from the interior grille served by that branch duct to the exterior hood,
when sizing a trunk duct, "maximum length of duct" refers to the physical length of the duct from the interior grille of the longest branch served by that trunk to the exterior hood,
outdoor air supply ducts shall be sized as trunk ducts,
"maximum airflow in duct" refers to the maximum airflow rate that a given section of duct (branch or trunk)must provide to satisfy the ventilation system design, and
"fan's external static pressure" refers to the external static pressure at which the fan is rated to achieve the maximum airflow rate that the fan is required or intended to provide.
Where flexible duct is used, it may be sized by choosing the next higher diameter in Table 9.32.3.11.-A or by choosing the diameter for a duct twice as long as the actual length.
Where rectangular duct is used in place of round duct, it shall be selected according to Table 9.32.3.11.-B.
Table 9.32.3.11.-B Equivalent Duct Sizes
Forming Part of Sentences 9.32.3.11.(9) and (12)
This Article shall apply to heat recovery ventilators installed to provide one or more of the fans required by this Subsection.
Two or more heat recovery ventilators shall not be connected in parallel airflow to a common air supply duct, unless specifically permitted by the manufacturer.
Two or more heat recovery ventilators shall not be connected in parallel airflow to a common downstream exhaust duct.
All start-up procedures recommended by the manufacturer, including air balancing and airflow determination, shall be followed.
A means for the free flow of condensate shall be provided in accordance with the manufacturer's recommendations or, in their absence, a condensate drain of at least 1/2 inch nominal pipe size pitched in the direction of flow and complete with a trap or condensate pump of sufficient capacity shall be installed and connected to the dwelling unit's drain, waste and vent system.
The heat recovery ventilator and all condensate lines shall be installed in a space where the ambient temperature will not adversely affect the operation of the system.
9.32.3.13.
Outdoor Intake and Exhaust Openings
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.
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.
The distance separating air intakes from building envelope penetrations that are potential sources of contaminants, such as gas vents or oil fill pipes, shall be not less than 900 mm.
Air intakes shall be clearly labeled as such for identification from locations outside the dwelling unit.
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.
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.
Air intake openings shall incorporate screens or grilles to protect against the entry of animals and insects.
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.
Screens, grilles and filters installed in air intake and exhaust openings shall be easily removable for cleaning purposes, without the need for special tools.
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.
Screens and grilles shall be of corrosion-resistant material.
Table 9.32.3.13. Area of Openings with Screens or Grilles
Forming Part of Sentence 9.32.3.13.(11)
