Division B
Acceptable Solutions

Heating-Season (Mechanical) Ventilation

(See Appendix A.)

Required Ventilation

Design and Installation

Mechanical Ventilation System Components

Principal Ventilation System Supply Air

(See Appendix A.)

Principal Ventilation System Exhaust Fan

Kitchen and Bathroom Exhaust Fans

Heated Crawl Space Ventilation

Air Ducts

Outdoor Inlets and Outlets

Interior Distribution

Heating-Season (Mechanical) Ventilation

(See Appendix A.)

Required Ventilation

Design and Installation

Mechanical Ventilation System Components

Principal Ventilation System Supply Air

(See Appendix A.)

Principal Ventilation System Exhaust Fan

Kitchen and Bathroom Exhaust Fans

Heated Crawl Space Ventilation

Air Ducts

Outdoor Inlets and Outlets

Interior Distribution

Heating-Season (Mechanical) Ventilation

(See Appendix A.)

Required Ventilation

Design and Installation

Mechanical Ventilation System Components

Principal Ventilation System Supply Air

(See Appendix A.)

Principal Ventilation System Exhaust Fan

Kitchen and Bathroom Exhaust Fans

Heated Crawl Space Ventilation

Air Ducts

Outdoor Inlets and Outlets

Interior Distribution

Heating-Season (Mechanical) Ventilation

(See Appendix A.)

Required Ventilation

Design and Installation

1) Exhaust fans and supply fans shall be installed in accordance with this Subsection and the manufacturer’s instructions.

2) The mechanical components of a mechanical ventilation system shall be installed so as to be accessible for inspection, maintenance, repair, and cleaning.

Mechanical Ventilation System Components

1) A mechanical ventilation system shall include

a) a principal ventilation system that

i) provides supply air in accordance with Article 9.32.3.4., and

ii) includes an exhaust fan that conforms with Article 9.32.3.5.,

b) the kitchen and bathroom exhaust fans that are required by Article 9.32.3.6., and

c) if the building includes a heated crawl space, the components that are required by Article 9.32.3.7.

Required Ventilation Capacity

1) Every dwelling unit shall be equipped with

a) a principal ventilation exhaust fan or ducted central ventilation system providing a minimum ventilation rate complying with Table 9.32.3.3.A, and

b) an exhaust fan with a minimum ventilation rate complying with Table 9.32.3.3.B in

i) every kitchen and

ii) every bathroom or water-closet room, unless the bathroom or water-closet room is served by a principle ventilation exhause fan or ducted central ventilation system providing a minimum ventilation rate complying with Table 9.32.3.3.B.

2) Where make-up air is required by Article 9.32.3.8. for a principal ventilation exhaust fan, the maximum ventilation rate shall not exceed 55 l/s (110 cfm).

Table Principal Exhaust Fan Ventilation Rate Forming part of Clause 9.32.3.3.(1)(a)
Number of Bedrooms	Minimum Ventilation Rate
	l/s
1	15
2	22
3	30
4 or more	35

Table Bathroom/Kitchen Exhaust Ventilation Rate Forming part of Clause 9.32.3.3.(1)(b)
Room	Minimum Exhaust Rate l/s
	Intermittent	Continuous
Kitchen	40	N/A
Bathroom	25	10

Principal Ventilation System Supply Air

(See Appendix A.)Appendix A.)

Principal Ventilation System Exhaust Fan

Kitchen and Bathroom Exhaust Fans

1) An exhaust fan that provides at least the air-flow rate specified in Table 9.32.3.6. shall be installed in

a) every kitchen, and

b) every bathroom or water-closet room, unless the bathroom or water-closet room is served by the principal ventilation system exhaust fan that complies with Article 9.32.3.5.

2) For the purposes of Sentence (1), the capacity rating of the exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Table Kitchen/Bathroom Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.6.(1)
Room	Minimum Exhaust Fan Air-flow Rate, L/s
Intermittent	Continuous
Kitchen	47	N/A
Bathroom	23	9

Heated Crawl Space Ventilation

1) Where a crawl space is heated by a ducted forced-air heating system that does not draw air from the crawl space to the furnace through the return air plenum, the crawl space shall be connected to the floor space above the crawl space by at least one air-transfer grille.

2) Where a crawl space is heated other than by a ducted forced-air heating system, the crawl space shall

a) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the principal ventilation system by a supply air outlet or an exhaust air inlet,

b) be connected to the floor space above the crawl space by at least 2 air-transfer grilles, or

c) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the outdoors by a dedicated exhaust fan that complies with Sentence (4).

3) An air-transfer grille required by Sentence (1) or (2) shall have an unobstructed vent area of the greater of

a) 25 cm², and

b) 0.83 cm² for every m² of crawl space area.

4) Where a dedicated exhaust fan is installed in accordance with Subclause (2)(c)(ii), the dedicated exhaust fan shall

a) provide an air-flow rate of at least 23 L/s, and

b) be controlled by

i) a humidity control device, or

ii) an adjustable time control device that is capable of providing not less than 8 total hours of ventilation per 24 hour period.

5) Where a crawl space is divided into 2 or more compartments, each heated compartment shall conform to Sentence (1) or (2).

Principal Ventilation Exhaust Fan Sound Rating

1) Wall and ceiling fans used as a principal ventilation exhaust fan shall not have a sound rating exceeding

a) 1.5 Sone when controlled by an adjustable time control device, or

b) 1.0 Sone when designed to run continuously.

2) The principal ventilation exhaust fan sound rating shall be determined in accordance with

a) HVI 915, “Procedure for Loudness Rating of Residential Fan Products,” or

b) CAN/CSA-C260-M90, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Air Ducts

1) Exhaust ducts shall discharge to the outdoors.

2) Exhaust ducts that are downstream of an exhaust fan shall have no connections to other fans or ducts.

3) Exhaust ducts, and supply ducts that conduct heated or cooled air, shall

a) be sized in accordance with the requirements of the manufacturer of the fans to which they are connected, and

b) have an equivalent diameter not less than that specified by Table 9.32.3.8.(3).

Table Maximum Equivalent Duct Length(1), m Forming part of Sentence 9.32.3.8.(3)
Flexible Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
125 (123)	32	15	—	—	—	—
150 (177)	46	40	28	18	13	—
175 (240)	46	46	46	46	46	24
200 (314)	46	46	46	46	46	46
Rigid Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
100 (79)	32	15	—	—	—	—
125 (123)	46	40	28	18	13	—
150 (177)	46	46	46	42	34	24
175 (240)	46	46	46	46	46	46

Notes to Table 9.32.3.8.(3):
(1)	The equivalent length of a duct is the length of the duct plus 10 m for the exterior hood and 3 m for each 90° elbow.

4) Where an exhaust duct passes through or is located adjacent to a space that is not conditioned space, the duct shall conform to Article 9.32.3.2., except that in no case shall such a duct be insulated to less than RSI 0.75.

5) Where a principal ventilation system supply duct passes through or is located adjacent to a conditioned space, the duct shall be

a) insulated to not less than RSI 0.75, and

b) provided with an effective vapour barrier.

6) Where a kitchen exhaust fan grille is installed within 1.2 m horizontally of a cooktop, the exhaust fan duct shall

a) be constructed of a material that is noncombustible, corrosion-resistant, and cleanable, and

b) be equipped with a grease filter at the intake end.

7) Except for a supply air system described in Sentence 9.32.3.4.(2) or (3) , all joints in exhaust ducts, and in supply ducts that conduct conditioned air, shall be sealed against air leakage with

a) sealants or gaskets made from liquids, mastics or heat-applied materials,

b) mastic with embedded fabric,

c) foil-faced butyl tape, or

d) aluminum foil tape.

8) Supply ducts for a mechanical ventilation system shall not be used to provide combustion or dilution air to fuel-burning appliances.

Kitchen and Bathroom Ventilation Exhaust Fan Capacity Ratings

1) Kitchen and bathroom ventilation exhaust fan capacity ratings shall be based on air flow performance at 50 pa external static pressure as determined in accordance with

a) HVI 916, “Airflow Test Standard,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Required Make-up Air for Principal Ventilation Exhaust Fan

1) Make-up ventilation air shall be provided from the outdoors where

a) a dwelling unit contains a naturally aspirating fuel-fired vented appliance that is subject to back drafting (See Appendix A), or

b) the dwelling unit is located in an area where soil gas is deemed to be a problem and incorporates no soil gas mitigation system

2) Where make-up air is required, the make-up air supply shall

a) when not connected to a forced air heating duct system be sized in accordance with Table 9.32.3.8. for the rating of the principal exhaust fan installed, or

b) when connected to the return air duct of a forced air heating appliance,

i) have an outdoor air supply duct size of 100 mm diameter for smooth duct or 125 mm diameter for insulated flex duct or equivalent area, and

ii) have the outdoor air supply duct connected not more than 5 m or, unless a flow control device is used, less than 3 m upstream of the return air connection to the furnace cabinet,

iii) have the furnace air circulating fan interconnected with the principal ventilation exhaust fan, and

iv) where the winter design temperature is colder than -10°C, have a duct provided with a motorized damper also interconnected with the principal ventilation exhaust fan.

3) Where make-up ventilation air is provided as required by Clause 9.32.3.8.(1)(a), in geographic areas where the winter design temperature is warmer than -10°C, it shall be delivered by

a) ducting into secondary areas such as a utility or storage room,

b) specially designed inlets in the upper sash or high on a wall, or

c) another method that avoids creating a cold draft or otherwise prevents occupants from blocking the ventilation.

4) Where make-up ventilation air is provided as required by Clause 9.32.3.8.(1)(a) in geographic areas where the winter design temperature is colder than -10°C, it shall be delivered as described in Sentence (3) with the addition of heat.

5) Systems or ducts designed to provide combustion air, dilution air or both for fuel-burning appliances shall not be used to supply make-up air for ventilation systems.

Table Passive Make-up Air Opening Size Forming part of Sentence 9.32.3.8.(2)
Maximum Exhaust Fan Ventilation Rate	Minimum Make-up Air Duct Size
	Vent Area	Vent Diameter
l/s	cm2	mm
8	47	80
12	66	90
15	85	100
17	95	110
20	114	120
25	142	130
30	170	150
35	199	160
40	227	170
45	255	180
50	284	190
55	312	200
60	340	210

6) Reserved.

7) Reserved.

8) The provision of makeup air as described in Sentence (1) is not required for mechanical exhausting devices operating a subfloor depressurization system installed for the purpose of reducing the risk of radon ingress.

Exhaust and Make-up Air Ducts

1) Exhaust ducts serving wall or ceiling exhaust fans shall be sized in accordance with Table 9.32.3.9.

2) Exhaust ducts shall discharge directly to the outdoors.

3) Where an exhaust duct passes through or is located adjacent to an unheated space, the duct shall be insulated to not less than RSI 0.75.

4) Where a ventilation air supply duct passes through a heated space the duct shall be insulated to not less than RSI 0.75 and provided with an effective vapour barrier.

5) Where an exhaust duct exceeds 30 m in total equivalent length, using an equivalent length of 10 m for the exterior hood and 3 m for each 90 degree elbow, the duct shall be increased to the next diameter.

6) Ductwork for range hoods and range-top fans shall

a) be of noncombustible, corrosion-resistant material,

b) lead directly to the outdoors with no connections to other exhaust fans or ducts, and

c) be equipped with a grease filter at the intake end.

Table Minimum Exhaust Duct Size Forming part of Article 9.32.3.9.
Maximum Exhaust Fan Ventilation Rate, l/s	Minimum Exhaust Duct Diameter, mm
	Smooth Duct	Flexible Duct
10	75	100
25	100	125
45	125	150
70	150	175

Outdoor Inlets and OutletsProtection from Weather

Exhaust Fan Installation

1) Installation of exhaust fans shall be in accordance with manufacturer's instructions for minimizing noise and vibration transmission and achieving the required sound rating.

Accessibility

1) Ventilation equipment shall be accessible for inspection, maintenance, repair and cleaning.

2) Except where the kitchen exhaust grille is located at least 1.2 m horizontally from the range or equipped with an intake filter, kitchen exhaust ducts shall be designed and installed so that the entire duct can be cleaned.

Ventilation Ducts

1) Except as required by Sentence 9.32.3.9.(6), ventilation air ducts serving general exhaust and supply ventilation air are permitted to be of combustible material.

Interior Distribution

Heating-Season (Mechanical) Ventilation

(See Appendix A.)

Required Ventilation

Design and Installation

1) Exhaust fans and supply fans shall be installed in accordance with this Subsection and the manufacturer’s instructions.

2) The mechanical components of a mechanical ventilation system shall be installed so as to be accessible for inspection, maintenance, repair, and cleaning.

Mechanical Ventilation System Components

1) A mechanical ventilation system shall include

a) a principal ventilation system that

i) provides supply air in accordance with Article 9.32.3.4., and

ii) includes an exhaust fan that conforms with Article 9.32.3.5.,

b) the kitchen and bathroom exhaust fans that are required by Article 9.32.3.6., and

c) if the building includes a heated crawl space, the components that are required by Article 9.32.3.7.

Required Ventilation Capacity

1) Every dwelling unit shall be equipped with

a) a principal ventilation exhaust fan or ducted central ventilation system providing a minimum ventilation rate complying with Table 9.32.3.3.A, and

b) an exhaust fan with a minimum ventilation rate complying with Table 9.32.3.3.B in

i) every kitchen and

ii) every bathroom or water-closet room, unless the bathroom or water-closet room is served by a principle ventilation exhause fan or ducted central ventilation system providing a minimum ventilation rate complying with Table 9.32.3.3.B.

2) Where make-up air is required by Article 9.32.3.8. for a principal ventilation exhaust fan, the maximum ventilation rate shall not exceed 55 l/s (110 cfm).

Table Principal Exhaust Fan Ventilation Rate Forming part of Clause 9.32.3.3.(1)(a)
Number of Bedrooms	Minimum Ventilation Rate
	l/s
1	15
2	22
3	30
4 or more	35

Table Bathroom/Kitchen Exhaust Ventilation Rate Forming part of Clause 9.32.3.3.(1)(b)
Room	Minimum Exhaust Rate
	Intermittent	Continuous
Kitchen	40	N/A
Bathroom	25	10

Principal Ventilation System Supply Air

(See Appendix A.)

1) Except as provided in Sentence (6), a principal ventilation system shall mechanically provide supply air in accordance with Sentence (2), (3), (4) or (5).

2) Where the principal ventilation system is a ducted forced-air heating system, the ducted forced-air heating system shall

a) provide supply air through the ducting to

i) each bedroom, and

ii) each floor level without a bedroom,

b) draw supply air from an outdoor inlet that is connected to the cabinet containing the furnace air circulating fan required by Clause (d) by ducting that measures, from that cabinet to the point at which the ducting intersects the return air plenum,

i) between 3 m and 4.5 m in length, or

ii) if a flow control device is used, not more than 4.5 m in length.

c) draw supply air through ducting that is

i) rigid ducting with an equivalent diameter of at least 100 mm, or

ii) flexible ducting with an equivalent diameter of at least 125 mm, and

d) have a furnace air circulating fan set to run continuously.

3) Where the principal ventilation system is a ducted forced-air heating system used in combination with a heat-recovery ventilator,

a) the ducted forced-air heating system shall conform to Clauses (2)(a), (c) and (d),

b) the heat-recovery ventilator shall draw supply air from an outdoor inlet into the return air plenum of the ducted forced-air heating system, and

c) the heat-recovery ventilator shall draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

4) Where the principal ventilation system is a heat-recovery ventilator, the heat-recovery ventilator shall

a) provide supply air through dedicated ducting to

i) each bedroom, and

ii) each floor level without a bedroom, and

b) draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

5) Where the principal ventilation system is a ducted central-recirculation ventilation system, the ducted central-recirculation ventilation system shall

a) draw supply air from an outdoor inlet connected upstream of the fan, and

b) draw air from

i) each bedroom and deliver it to a common area, or

ii) a common area and deliver it to each bedroom.

6) A principal ventilation system need not conform to Sentence (1) if the principal ventilation system

a) services a dwelling unit that

i) is located where the January design temperature, on a 2.5% basis determined in conformance with Article 1.1.3.1., is greater than −20°C,

ii) has only 1 storey and a floor area of less than 168 m² within the building envelope (see Appendix A),

iii) does not have a ducted forced-air heating system, and

iv) except for a secondary suite, is not located in a building conforming to Subsection 9.36.6. or 10.2.3., and

b) provides supply air passively from outdoors through dedicated inlets that

i) are located in each bedroom and at least one common area,

ii) are located at least 1 800 mm above the floor, and

iii) have an unobstructed vent area of not less than 25 cm².

Principal Exhaust Fan Control

1) The principal ventilation exhaust fan shall

a) be controlled by an adjustable time control device capable of providing not less than 8 total hours of ventilation in not less than 2 periods per 24 hr day, and have a separate manual switch when serving both the principle ventilation exhaust function and a bathroom or water-closet room exhaust function, or

b) be designed to run continuously.

Principal Ventilation System Exhaust Fan

Kitchen and Bathroom Exhaust Fans

1) An exhaust fan that provides at least the air-flow rate specified in Table 9.32.3.6. shall be installed in

a) every kitchen, and

b) every bathroom or water-closet room, unless the bathroom or water-closet room is served by the principal ventilation system exhaust fan that complies with Article 9.32.3.5.

2) For the purposes of Sentence (1), the capacity rating of the exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Table Kitchen/Bathroom Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.6.(1)
Room	Minimum Exhaust Fan Air-flow Rate, L/s
Intermittent	Continuous
Kitchen	47	N/A
Bathroom	23	9

Principal Ventilation Exhaust Fan Capacity Rating

1) The principal ventilation exhaust fan capacity rating shall be based on air flow performance at 50 pa external static pressure as determined in accordance with

a) HVI 916 “Airflow Test Standard,” or

b) CAN/CSA-C260-M90, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Heated Crawl Space Ventilation

1) Where a crawl space is heated by a ducted forced-air heating system that does not draw air from the crawl space to the furnace through the return air plenum, the crawl space shall be connected to the floor space above the crawl space by at least one air-transfer grille.

2) Where a crawl space is heated other than by a ducted forced-air heating system, the crawl space shall

a) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the principal ventilation system by a supply air outlet or an exhaust air inlet,

b) be connected to the floor space above the crawl space by at least 2 air-transfer grilles, or

c) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the outdoors by a dedicated exhaust fan that complies with Sentence (4).

3) An air-transfer grille required by Sentence (1) or (2) shall have an unobstructed vent area of the greater of

a) 25 cm², and

b) 0.83 cm² for every m² of crawl space area.

4) Where a dedicated exhaust fan is installed in accordance with Subclause (2)(c)(ii), the dedicated exhaust fan shall

a) provide an air-flow rate of at least 23 L/s, and

b) be controlled by

i) a humidity control device, or

ii) an adjustable time control device that is capable of providing not less than 8 total hours of ventilation per 24 hour period.

5) Where a crawl space is divided into 2 or more compartments, each heated compartment shall conform to Sentence (1) or (2).

Kitchen and Bathroom Ventilation Exhaust Fan Capacity Ratings

1) Kitchen and bathroom ventilation exhaust fan capacity ratings shall be based on air flow performance at 50 pa external static pressure as determined in accordance with

a) HVI 916, “Airflow Test Standard,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Air Ducts

1) Exhaust ducts shall discharge to the outdoors.

2) Exhaust ducts that are downstream of an exhaust fan shall have no connections to other fans or ducts.

3) Exhaust ducts, and supply ducts that conduct heated or cooled air, shall

a) be sized in accordance with the requirements of the manufacturer of the fans to which they are connected, and

b) have an equivalent diameter not less than that specified by Table 9.32.3.8.(3).

Table Maximum Equivalent Duct Length(1), m Forming part of Sentence 9.32.3.8.(3)
Flexible Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
125 (123)	32	15	—	—	—	—
150 (177)	46	40	28	18	13	—
175 (240)	46	46	46	46	46	24
200 (314)	46	46	46	46	46	46
Rigid Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
100 (79)	32	15	—	—	—	—
125 (123)	46	40	28	18	13	—
150 (177)	46	46	46	42	34	24
175 (240)	46	46	46	46	46	46

Notes to Table 9.32.3.8.(3):
(1)	The equivalent length of a duct is the length of the duct plus 10 m for the exterior hood and 3 m for each 90° elbow.

4) Where an exhaust duct passes through or is located adjacent to a space that is not conditioned space, the duct shall conform to Article 9.32.3.2., except that in no case shall such a duct be insulated to less than RSI 0.75.

5) Where a principal ventilation system supply duct passes through or is located adjacent to a conditioned space, the duct shall be

a) insulated to not less than RSI 0.75, and

b) provided with an effective vapour barrier.

6) Where a kitchen exhaust fan grille is installed within 1.2 m horizontally of a cooktop, the exhaust fan duct shall

a) be constructed of a material that is noncombustible, corrosion-resistant, and cleanable, and

b) be equipped with a grease filter at the intake end.

7) Except for a supply air system described in Sentence 9.32.3.4.(2) or (3) , all joints in exhaust ducts, and in supply ducts that conduct conditioned air, shall be sealed against air leakage with

a) sealants or gaskets made from liquids, mastics or heat-applied materials,

b) mastic with embedded fabric,

c) foil-faced butyl tape, or

d) aluminum foil tape.

8) Supply ducts for a mechanical ventilation system shall not be used to provide combustion or dilution air to fuel-burning appliances.

Required Make-up Air for Principal Ventilation Exhaust Fan

1) Make-up ventilation air shall be provided from the outdoors where

a) a dwelling unit contains a naturally aspirating fuel-fired vented appliance that is subject to back drafting (See Appendix A), or

b) the dwelling unit is located in an area where soil gas is deemed to be a problem and incorporates no soil gas mitigation system

2) Where make-up air is required, the make-up air supply shall

a) when not connected to a forced air heating duct system be sized in accordance with Table 9.32.3.8. for the rating of the principal exhaust fan installed, or

b) when connected to the return air duct of a forced air heating appliance,

i) have an outdoor air supply duct size of 100 mm diameter for smooth duct or 125 mm diameter for insulated flex duct or equivalent area, and

ii) have the outdoor air supply duct connected not more than 5 m or, unless a flow control device is used, less than 3 m upstream of the return air connection to the furnace cabinet,

iii) have the furnace air circulating fan interconnected with the principal ventilation exhaust fan, and

iv) where the winter design temperature is colder than -10°C, have a duct provided with a motorized damper also interconnected with the principal ventilation exhaust fan.

3) Where make-up ventilation air is provided as required by Clause 9.32.3.8.(1)(a), in geographic areas where the winter design temperature is warmer than -10°C, it shall be delivered by

a) ducting into secondary areas such as a utility or storage room,

b) specially designed inlets in the upper sash or high on a wall, or

c) another method that avoids creating a cold draft or otherwise prevents occupants from blocking the ventilation.

4) Where make-up ventilation air is provided as required by Clause 9.32.3.8.(1)(a) in geographic areas where the winter design temperature is colder than -10°C, it shall be delivered as described in Sentence (3) with the addition of heat.

5) Systems or ducts designed to provide combustion air, dilution air or both for fuel-burning appliances shall not be used to supply make-up air for ventilation systems.

Table Passive Make-up Air Opening Size Forming part of Sentence 9.32.3.8.(2)
Maximum Exhaust Fan Ventilation Rate	Minimum Make-up Air Duct Size
	Vent Area	Vent Diameter
l/s	cm2	mm
8	47	80
12	66	90
15	85	100
17	95	110
20	114	120
25	142	130
30	170	150
35	199	160
40	227	170
45	255	180
50	284	190
55	312	200
60	340	210

6) Reserved.

7) Reserved.

8) The provision of makeup air as described in Sentence (1) is not required for mechanical exhausting devices operating a subfloor depressurization system installed for the purpose of reducing the risk of radon ingress.

Exhaust and Make-up Air Ducts

1) Exhaust ducts serving wall or ceiling exhaust fans shall be sized in accordance with Table 9.32.3.9.

2) Exhaust ducts shall discharge directly to the outdoors.

3) Where an exhaust duct passes through or is located adjacent to an unheated space, the duct shall be insulated to not less than RSI 0.75.

4) Where a ventilation air supply duct passes through a heated space the duct shall be insulated to not less than RSI 0.75 and provided with an effective vapour barrier.

5) Where an exhaust duct exceeds 30 m in total equivalent length, using an equivalent length of 10 m for the exterior hood and 3 m for each 90 degree elbow, the duct shall be increased to the next diameter.

6) Ductwork for range hoods and range-top fans shall

a) be of noncombustible, corrosion-resistant material,

b) lead directly to the outdoors with no connections to other exhaust fans or ducts, and

c) be equipped with a grease filter at the intake end.

Table Minimum Exhaust Duct Size Forming part of Article 9.32.3.9.
Maximum Exhaust Fan Ventilation Rate, l/s	Minimum Exhaust Duct Diameter, mm
	Smooth Duct	Flexible Duct
10	75	100
25	100	125
45	125	150
70	150	175

Outdoor Inlets and OutletsProtection from Weather

Exhaust Fan Installation

1) Installation of exhaust fans shall be in accordance with manufacturer's instructions for minimizing noise and vibration transmission and achieving the required sound rating.

Accessibility

1) Ventilation equipment shall be accessible for inspection, maintenance, repair and cleaning.

2) Except where the kitchen exhaust grille is located at least 1.2 m horizontally from the range or equipped with an intake filter, kitchen exhaust ducts shall be designed and installed so that the entire duct can be cleaned.

Ventilation Ducts

1) Except as required by Sentence 9.32.3.9.(6), ventilation air ducts serving general exhaust and supply ventilation air are permitted to be of combustible material.

Interior Distribution

Heating-Season (Mechanical)Mechanical Ventilation

(See Appendix A.)

Required Ventilation

2) Mechanical ventilation systems complying with the balance of this Subsection shall incorporate at least the following components:

a) a principal ventilation system complying with Article 9.32.3.3.,

b) supplemental exhaust fans complying with Article 9.32.3.7., and

c) protection against depressurization in accordance with Article 9.32.3.8.

Design and Installation

1) Exhaust fans and supply fans shall be installed in accordance with this Subsection and the manufacturer’s instructions.

2) 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.

3) 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.

4) Where flow-regulating dampers are required,

a) they shall be adjustable and accessible without requiring the removal of fans, motors or insulating materials, or the use of specialized tools, and

b) a device on the outside of the duct or device in which they are installed shall indicate the position of the damper.

6) 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.

Mechanical Ventilation System Components

1) A mechanical ventilation system shall include

a) a principal ventilation system that

i) provides supply air in accordance with Article 9.32.3.4., and

ii) includes an exhaust fan that conforms with Article 9.32.3.5.,

b) the kitchen and bathroom exhaust fans that are required by Article 9.32.3.6., and

c) if the building includes a heated crawl space, the components that are required by Article 9.32.3.7.

Principal Ventilation System

(See Appendix A.)

1) The principal ventilation system shall incorporate the following components:

a) a principal ventilation fan complying with this Article, and

b) 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.

2) 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 Appendix A.)

Table Forming part of Sentence 9.32.3.3.(2)
Number of Bedrooms in Dwelling Unit	Normal Operating Exhaust Capacity of Principal Ventilation Fan, L/s
	Minimum	Maximum
1	16	24
2	18	28
3	22	32
4	26	38
5	30	45
More than 5	System must comply with Clause 9.32.3.1.(1)(a)

3) 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 Appendix A.)

4) The components of the principal ventilation system shall be approved by their manufacturer for continuous operation.

5) 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 Appendix A.)

6) If all controls serving the principal ventilation fan are in the “off” position, the principal ventilation system shall not operate.

7) 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

a) the automatic control is located within the living area of the dwelling unit, and

b) the manual override is clearly marked “VENTILATION FAN.”

8) 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.

9) 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).

10) 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 Appendix A.)

Ventilation Systems Used in Conjunction with Forced Air Heating Systems

(See Appendix A.)

1) 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.

2) 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

a) 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

b) 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.

Table Maximum Outdoor Airflow Forming part of Sentence 9.32.3.4.(2)
January 2.5% Temperature as per Appendix C, °C	Maximum Outdoor Airflow for Indicated Mixed Temperature, L/s
	0	0	0	-10	-10	-10	-20	-20	-20	-30	-30	-30	-40	-40	-40	-50	-50	-50
Minimum Mixed Air Temperature, °C	15	10	5	15	10	5	15	10	5	15	10	5	15	10	5	15	10	5
Furnace Airflow, L/s
0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
100	32	55	77	22	38	53	17	29	40	13	23	33	11	19	27	10	17	24
200	64	109	155	44	75	106	33	57	81	27	46	65	23	39	55	19	33	47
300	—	—	—	66	113	159	50	86	121	40	69	98	34	58	82	29	50	71
400	—	—	—	—	—	—	—	—	—	54	92	131	45	77	110	39	67	94
500	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	49	83	118

3) For the purposes of Table 9.32.3.4., the furnace airflow shall be determined

a) 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

b) 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).

4) Linear interpolation is permitted in using Table 9.32.3.4.

5) An outdoor air supply duct shall be installed between the outdoors and the furnace return air plenum and shall be connected

a) not less than 3 m upstream of the plenum connection to the furnace, as measured along the length of the duct, or

b) through an acceptable mixing device installed in the return air plenum.

6) The outdoor air supply duct required by Sentence (5) shall incorporate a flow-regulating damper.

7) 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.

8) 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

a) approved by the manufacturer for the handling of untempered outdoor air if it will be handling untempered outdoor air,

b) approved by the manufacturer for continuous operation, and

c) 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.

9) The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that

a) 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,

b) where applicable, activation of the principal ventilation fan automatically activates the auxiliary outdoor air supply fan described in Sentence (8), and

c) the auxiliary outdoor air supply fan does not operate when the principal ventilation fan is not operating.

10) 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.

11) 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.

12) 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.

Ventilation Systems Not Used in Conjunction with Forced Air Heating Systems

(See Appendix A.)

1) 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.

2) 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.

3) The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that

a) activation of the principal ventilation fan automatically activates the outdoor air supply fan required by Sentence (2), and

b) the outdoor air supply fan does not operate when the principal ventilation fan is not operating.

4) The outdoor air supply fan shall be connected to the outdoors through an outdoor air supply duct.

5) The outdoor air supply duct required by Sentence (4) shall incorporate a flow-regulating damper.

6) 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.

7) The airflow measurements required by Sentence (6) shall be done using a method accurate to within ±15% of the flow rate being measured.

8) 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.

9) 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.

10) 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

a) each bedroom,

b) any storey, including basements and heated crawl spaces, without a bedroom, and

c) if there is no storey without a bedroom, to the principal living area.

11) 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.

12) All branch supply ducts that are not fitted with diffusers with adjustable balance stops shall be supplied with balancing dampers that

a) can be fixed in their adjusted positions, and

b) include devices to indicate the positions of the dampers.

13) 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.

14) 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.

Principal Ventilation System Supply Air

(See Appendix A.)

1) Except as provided in Sentence (6), a principal ventilation system shall mechanically provide supply air in accordance with Sentence (2), (3), (4) or (5).

2) Where the principal ventilation system is a ducted forced-air heating system, the ducted forced-air heating system shall

a) provide supply air through the ducting to

i) each bedroom, and

ii) each floor level without a bedroom,

b) draw supply air from an outdoor inlet that is connected to the cabinet containing the furnace air circulating fan required by Clause (d) by ducting that measures, from that cabinet to the point at which the ducting intersects the return air plenum,

i) between 3 m and 4.5 m in length, or

ii) if a flow control device is used, not more than 4.5 m in length.

c) draw supply air through ducting that is

i) rigid ducting with an equivalent diameter of at least 100 mm, or

ii) flexible ducting with an equivalent diameter of at least 125 mm, and

d) have a furnace air circulating fan set to run continuously.

3) Where the principal ventilation system is a ducted forced-air heating system used in combination with a heat-recovery ventilator,

a) the ducted forced-air heating system shall conform to Clauses (2)(a), (c) and (d),

b) the heat-recovery ventilator shall draw supply air from an outdoor inlet into the return air plenum of the ducted forced-air heating system, and

c) the heat-recovery ventilator shall draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

4) Where the principal ventilation system is a heat-recovery ventilator, the heat-recovery ventilator shall

a) provide supply air through dedicated ducting to

i) each bedroom, and

ii) each floor level without a bedroom, and

b) draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

5) Where the principal ventilation system is a ducted central-recirculation ventilation system, the ducted central-recirculation ventilation system shall

a) draw supply air from an outdoor inlet connected upstream of the fan, and

b) draw air from

i) each bedroom and deliver it to a common area, or

ii) a common area and deliver it to each bedroom.

6) A principal ventilation system need not conform to Sentence (1) if the principal ventilation system

a) services a dwelling unit that

i) is located where the January design temperature, on a 2.5% basis determined in conformance with Article 1.1.3.1., is greater than −20°C,

ii) has only 1 storey and a floor area of less than 168 m² within the building envelope (see Appendix A),

iii) does not have a ducted forced-air heating system, and

iv) except for a secondary suite, is not located in a building conforming to Subsection 9.36.6. or 10.2.3., and

b) provides supply air passively from outdoors through dedicated inlets that

i) are located in each bedroom and at least one common area,

ii) are located at least 1 800 mm above the floor, and

iii) have an unobstructed vent area of not less than 25 cm².

Exhaust-Only Ventilation Systems

(See Appendix A.)

1) A ventilation system with no provision for the introduction of outdoor air to the dwelling unit may only be used where the dwelling unit

a) 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

b) 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.

2) 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.

3) 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.

Principal Ventilation System Exhaust Fan

1) A principal ventilation system exhaust fan shall

a) run continuously, and

b) provide at least the air-flow rate specified in Table 9.32.3.5.

Table Principal Ventilation System Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.5.(1)
Floor Area, m2	Minimum Air-flow Rate, L/s
Number of Bedrooms
0–1	2–3	4–5	6–7	>7
< 140	14	21	28	35	42
140–280	21	28	35	42	49
281–420	28	35	42	49	56
421–560	35	42	49	56	64
561–700	42	49	56	64	71
> 700	49	56	64	71	78

2) For the purposes of Sentence (1), the capacity rating of the principal ventilation system exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

3) The principal ventilation system exhaust fan shall be

a) designed to run continuously, and

b) controlled by a dedicated switch that

i) has 2 settings, on and off,

ii) is located where it will be accessible for the purposes of servicing the exhaust fan but not likely to be turned off inadvertently, and

iii) is clearly marked “PRINCIPAL VENTILATION EXHAUST FAN.”

4) If the principal ventilation system exhaust fan is designed to run at multiple air-flow rates,

a) the air-flow rate of the fan shall be controlled by a switch other than the switch described in Clause (3)(b), and

b) the lowest air-flow rate shall not be less than the air-flow rate specified in Table 9.32.3.5.

5) The sound rating of the principal ventilation system exhaust fan shall not exceed 1.0 sone when running continuously at the air-flow rate specified in Table 9.32.3.5. as determined in accordance with

a) HVI Publication 915, “Loudness Testing and Rating Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Supplemental Exhaust

(See Appendix A.)

1) 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.

2) 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.

3) A supplemental exhaust fan is not required in a kitchen where the principal ventilation fan draws from that kitchen and other rooms, provided

a) 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

b) the high exhaust rate of the principal ventilation fan, as described in Clause (a), is activated by a manual switch in the kitchen labelled “KITCHEN EXHAUST.”

4) 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.

5) 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.

6) A supplemental exhaust fan required by this Article shall be controlled by a manual switch located in the room served by the fan.

7) 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).

8) 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.

Kitchen and Bathroom Exhaust Fans

1) An exhaust fan that provides at least the air-flow rate specified in Table 9.32.3.6. shall be installed in

a) every kitchen, and

b) every bathroom or water-closet room, unless the bathroom or water-closet room is served by the principal ventilation system exhaust fan that complies with Article 9.32.3.5.

2) For the purposes of Sentence (1), the capacity rating of the exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Table Kitchen/Bathroom Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.6.(1)
Room	Minimum Exhaust Fan Air-flow Rate, L/s
Intermittent	Continuous
Kitchen	47	N/A
Bathroom	23	9

Protection Against Depressurization

(See Appendix A.)

1) This Article applies to

a) 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

b) 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.

2) 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

a) not less than the exhaust capacity of the device, and

b) not greater than that exhaust capacity plus 10%.

3) 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.

4) The outdoor makeup air required by Sentence (2) shall be

a) introduced to a normally unoccupied area in the dwelling unit, or

b) tempered to at least 12°C before being introduced to occupied areas or to a supply duct system.

5) 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.

6) 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.

7) 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, “The Spillage Test: Method to Determine the Potential for Pressure-Induced Spillage from Vented, Fuel-Fired, Space Heating Applicances, Water Heaters and Fireplaces,” 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.

8) 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.

Heated Crawl Space Ventilation

1) Where a crawl space is heated by a ducted forced-air heating system that does not draw air from the crawl space to the furnace through the return air plenum, the crawl space shall be connected to the floor space above the crawl space by at least one air-transfer grille.

2) Where a crawl space is heated other than by a ducted forced-air heating system, the crawl space shall

a) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the principal ventilation system by a supply air outlet or an exhaust air inlet,

b) be connected to the floor space above the crawl space by at least 2 air-transfer grilles, or

c) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the outdoors by a dedicated exhaust fan that complies with Sentence (4).

3) An air-transfer grille required by Sentence (1) or (2) shall have an unobstructed vent area of the greater of

a) 25 cm², and

b) 0.83 cm² for every m² of crawl space area.

4) Where a dedicated exhaust fan is installed in accordance with Subclause (2)(c)(ii), the dedicated exhaust fan shall

a) provide an air-flow rate of at least 23 L/s, and

b) be controlled by

i) a humidity control device, or

ii) an adjustable time control device that is capable of providing not less than 8 total hours of ventilation per 24 hour period.

5) Where a crawl space is divided into 2 or more compartments, each heated compartment shall conform to Sentence (1) or (2).

Carbon Monoxide Alarms

(See Appendix A.)

1) This Article applies to every building that contains a residential occupancy and that also contains

a) a fuel-burning appliance, or

b) a storage garage.

2) Carbon monoxide (CO) alarms required by this Article shall

a) conform to CAN/CSA-6.19, “Residential Carbon Monoxide Alarming Devices,”

b) be equipped with an integral alarm that satisfies the audibility requirements of CAN/CSA-6.19, “Residential Carbon Monoxide Alarming Devices,”

c) 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

d) be mechanically fixed at a height recommended by the manufacturer.

3) 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

a) at the manufacturer’s recommended height where these instructions specifically mention solid-fuel-burning appliances, or

b) in the absence of specific instructions related to solid-fuel-burning appliances, on or near the ceiling.

4) Where a fuel-burning appliance is installed in a suite of residential occupancy, a CO alarm shall be installed

a) inside each bedroom, or

b) outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.

5) 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

a) 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

b) in the service room.

6) 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

a) inside each bedroom, or

b) outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.

Fans

(See Appendix A.)

1) Except as provided in Sentence (4), capacity ratings for required fans shall be determined in accordance with

a) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment,” or

b) HVI 916, “Airflow Test Standard.”

2) Sound ratings for fans shall be determined in accordance with

a) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment,” or

b) HVI 915, “Procedure for Loudness Rating of Residential Fan Products.”

3) Capacity ratings for fans shall be measured at the external static pressure differentials shown in Table 9.32.3.10.A.

4) 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.”

Table Minimum External Static Pressure Differential for Rating of Fans Forming part of Sentence 9.32.3.10.(3)
Fan Configuration or Application	Minimum External Static Pressure Differential to be Used in Determining Rated Capacity
Fans installed with ducts connected on both sides, any application	100 Pa (0.4 inch water column)
Fans installed with ducts on one side only, used as the principal ventilation fan in exhaust-only systems permitted by Article 9.32.3.6.	62 Pa (0.25 inch water column)
Other required fans	25 Pa (0.1 inch water column)

5) 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.

6) 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.

Table Maximum Sound Rating for Fans Forming part of Sentence 9.32.3.10.(6)
Fan Application	Maximum Sound Rating, sones
	Rated according to CAN/CSA-C260-M	Rated according to HVI 915
Principal ventilation fan	2.0	2.5
Supplemental fans installed in bathrooms and their makeup air fans	2.5	3.5
Supplemental fans installed in kitchens and their makeup air fans	No rating required	No rating required

7) Mechanical ventilation devices shall conform to CSA C22.2 No. 113-M, “Fans and Ventilators.”

Air Ducts

1) Exhaust ducts shall discharge to the outdoors.

2) Exhaust ducts that are downstream of an exhaust fan shall have no connections to other fans or ducts.

3) Exhaust ducts, and supply ducts that conduct heated or cooled air, shall

a) be sized in accordance with the requirements of the manufacturer of the fans to which they are connected, and

b) have an equivalent diameter not less than that specified by Table 9.32.3.8.(3).

Table Maximum Equivalent Duct Length(1), m Forming part of Sentence 9.32.3.8.(3)
Flexible Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
125 (123)	32	15	—	—	—	—
150 (177)	46	40	28	18	13	—
175 (240)	46	46	46	46	46	24
200 (314)	46	46	46	46	46	46
Rigid Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
100 (79)	32	15	—	—	—	—
125 (123)	46	40	28	18	13	—
150 (177)	46	46	46	42	34	24
175 (240)	46	46	46	46	46	46

Notes to Table 9.32.3.8.(3):
(1)	The equivalent length of a duct is the length of the duct plus 10 m for the exterior hood and 3 m for each 90° elbow.

4) Where an exhaust duct passes through or is located adjacent to a space that is not conditioned space, the duct shall conform to Article 9.32.3.2., except that in no case shall such a duct be insulated to less than RSI 0.75.

5) Where a principal ventilation system supply duct passes through or is located adjacent to a conditioned space, the duct shall be

a) insulated to not less than RSI 0.75, and

b) provided with an effective vapour barrier.

6) Where a kitchen exhaust fan grille is installed within 1.2 m horizontally of a cooktop, the exhaust fan duct shall

a) be constructed of a material that is noncombustible, corrosion-resistant, and cleanable, and

b) be equipped with a grease filter at the intake end.

7) Except for a supply air system described in Sentence 9.32.3.4.(2) or (3) , all joints in exhaust ducts, and in supply ducts that conduct conditioned air, shall be sealed against air leakage with

a) sealants or gaskets made from liquids, mastics or heat-applied materials,

b) mastic with embedded fabric,

c) foil-faced butyl tape, or

d) aluminum foil tape.

8) Supply ducts for a mechanical ventilation system shall not be used to provide combustion or dilution air to fuel-burning appliances.

Ducts

(See Appendix A.)

1) 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.

2) Exhaust ducts shall not discharge into heated or unheated enclosed spaces.

3) 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.

4) Where a duct carrying outdoor air that is not tempered and not mixed with indoor air passes through heated space, it shall be

a) insulated to not less than RSI 0.5, and

b) provided with a vapour barrier.

5) All exhaust intakes located within 3 m horizontally of a cooktop shall be equipped with a grease filter at the intake end.

6) Ductwork for cooking appliance exhaust fans shall

a) be of noncombustible, corrosion-resistant material,

b) lead directly to the outdoors with no connections to other exhaust fans or ducts, and

c) be equipped with a grease filter at the intake end.

7) All ductwork shall be installed to avoid crushing and shall be permanently supported to prevent sagging.

8) Joints in all ventilation system ducting shall be sealed with mastic, metal foil duct tape or the manufacturers' specified sealants.

9) 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 Equivalent Duct Sizes Forming part of Sentence 9.32.3.11.(9)
Fan's External Static Pressure, Pa	Duct Diameter, mm	Maximum Airflow in Duct, L/s
		7	15	25	35	50	75	100
		Maximum Length of Duct, m
25	75	6	1	0	0	0	0	0
	100	25	6	2	1	0	0	0
	125	60	17	6	3	1	0	0
	150	60	42	16	8	4	2	1
	175	60	60	34	18	9	4	2
	200	60	60	60	35	18	8	5
50	75	16	4	1	0	0	0	0
	100	60	16	6	3	1	0	0
	125	60	47	18	9	5	2	1
	150	60	60	44	23	12	5	3
	175	60	60	60	49	25	12	7
	200	60	60	60	60	48	22	13
62.5	75	22	5	2	1	0	0	0
	100	60	21	8	4	2	1	0
	125	60	60	24	12	6	3	1
	150	60	60	58	31	15	7	4
	175	60	60	60	60	33	15	9
	200	60	60	60	60	60	29	17
100	75	38	9	3	1	0	0	0
	100	60	36	14	7	3	1	1
	125	60	60	41	22	11	5	3
	150	60	60	60	53	27	12	7
	175	60	60	60	60	57	27	15
	200	60	60	60	60	60	51	30
150	75	59	14	5	2	1	0	0
	100	60	57	22	11	6	2	1
	125	60	60	60	34	17	8	4
	150	60	60	60	60	42	20	11
	175	60	60	60	60	60	42	24
	200	60	60	60	60	60	60	46

10) In using Table 9.32.3.11.A.,

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,

b) 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,

c) outdoor air supply ducts shall be sized as trunk ducts,

d) “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

e) “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.

11) 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.

12) Where rectangular duct is used in place of round duct, it shall be selected according to Table 9.32.3.11.B.

Table Equivalent Duct Sizes Forming part of Sentences 9.32.3.11.(9) and (12)
Required Round Duct Size, mm (in.)	Permitted Equivalent Rectangular Duct Size, mm (in.)
	Stack duct	100 mm (4 in.) depth	125 mm (5 in.) depth	150 mm (6 in.) depth
75 (3)	75 x 150 (3 x 6)	50 x 100 (2 x 4)	—	—
100 (4)	75 x 250 (3 x 10)	75 x 100 (3 x 4)	75 x 125 (3 x 5)	75 x 150 (3 x 6)
125 (5)	75 x 250 (3 x 10)	125 x 100 (5 x 4)	100 x 125 (4 x 5)	100 x 150 (4 x 6)
150 (6)	75 x 300 (3 x 14)	200 x 100 (8 x 4)	150 x 125 (6 x 5)	125 x 150 (5 x 6)
175 (7)	75 x 350 (3 x 14)	275 x 100 (11 x 4)	200 x 125 (8 x 5)	175 x 150 (7 x 6)
> 175 (> 7)	design to Subsection 9.33.4.

Outdoor Inlets and Outlets

1) Outdoor air inlets and exhaust outlets shall be shielded from the weather, birds and rodents by using hoods incorporating a screen of corrosion-resistant material with openings of 6 to 12 mm.

Heat Recovery Ventilators

(See Appendix A.)

1) This Article shall apply to heat recovery ventilators installed to provide one or more of the fans required by this Subsection.

2) 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.

3) Two or more heat recovery ventilators shall not be connected in parallel airflow to a common downstream exhaust duct.

4) All start-up procedures recommended by the manufacturer, including air balancing and airflow determination, shall be followed.

5) 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.

6) 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.

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 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.

4) Air intakes shall be clearly labeled as such for identification from locations outside the dwelling unit.

5) 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.

6) 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.

7) Air intake openings shall incorporate screens or grilles to protect against the entry of animals and insects.

8) Except for exhaust outlets serving heat recovery ventilators, exhaust outlets shall incorporate backdraft dampers.

9) 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.

10) Screens, grilles and filters installed in air intake and exhaust openings shall be easily removable for cleaning purposes, without the need for special tools.

11) 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.

12) Screens and grilles shall be of corrosion-resistant material.

Table Area of Openings with Screens or Grilles Forming part of Sentence 9.32.3.13.(11)
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

Interior Distribution

1) Interior doors shall be undercut by a minimum of 12 mm above the finished floor or the rooms shall be provided with an air-transfer grille with an unobstructed vent area that is not less than 100 cm².

Heating-Season (Mechanical)Mechanical Ventilation

(See Appendix A.)

Required Ventilation

2) Mechanical ventilation systems complying with the balance of this Subsection shall incorporate at least the following components:

a) a principal ventilation system complying with Article 9.32.3.3.,

b) supplemental exhaust fans complying with Article 9.32.3.7., and

c) protection against depressurization in accordance with Article 9.32.3.8.

Design and Installation

1) Exhaust fans and supply fans shall be installed in accordance with this Subsection and the manufacturer’s instructions.

2) 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.

3) 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.

4) Where flow-regulating dampers are required,

a) they shall be adjustable and accessible without requiring the removal of fans, motors or insulating materials, or the use of specialized tools, and

b) a device on the outside of the duct or device in which they are installed shall indicate the position of the damper.

6) 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.

Mechanical Ventilation System Components

1) A mechanical ventilation system shall include

a) a principal ventilation system that

i) provides supply air in accordance with Article 9.32.3.4., and

ii) includes an exhaust fan that conforms with Article 9.32.3.5.,

b) the kitchen and bathroom exhaust fans that are required by Article 9.32.3.6., and

c) if the building includes a heated crawl space, the components that are required by Article 9.32.3.7.

Principal Ventilation System

(See Appendix A.)

1) The principal ventilation system shall incorporate the following components:

a) a principal ventilation fan complying with this Article, and

b) 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.

2) 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 Appendix A.)

Table Forming part of Sentence 9.32.3.3.(2)
Number of Bedrooms in Dwelling Unit	Normal Operating Exhaust Capacity of Principal Ventilation Fan, L/s
	Minimum	Maximum
1	16	24
2	18	28
3	22	32
4	26	38
5	30	45
More than 5	System must comply with Clause 9.32.3.1.(1)(a)

3) 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 Appendix A.)

4) The components of the principal ventilation system shall be approved by their manufacturer for continuous operation.

5) 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 Appendix A.)

6) If all controls serving the principal ventilation fan are in the “off” position, the principal ventilation system shall not operate.

7) 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

a) the automatic control is located within the living area of the dwelling unit, and

b) the manual override is clearly marked “VENTILATION FAN.”

8) 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.

9) 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).

10) 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 Appendix A.)

Ventilation Systems Used in Conjunction with Forced Air Heating Systems

(See Appendix A.)

1) 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.

2) 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

a) 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

b) 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.

Table Maximum Outdoor Airflow Forming part of Sentence 9.32.3.4.(2)
January 2.5% Temperature as per Appendix C, °C	Maximum Outdoor Airflow for Indicated Mixed Temperature, L/s
	0	0	0	-10	-10	-10	-20	-20	-20	-30	-30	-30	-40	-40	-40	-50	-50	-50
Minimum Mixed Air Temperature, °C	15	10	5	15	10	5	15	10	5	15	10	5	15	10	5	15	10	5
Furnace Airflow, L/s
0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
100	32	55	77	22	38	53	17	29	40	13	23	33	11	19	27	10	17	24
200	64	109	155	44	75	106	33	57	81	27	46	65	23	39	55	19	33	47
300	—	—	—	66	113	159	50	86	121	40	69	98	34	58	82	29	50	71
400	—	—	—	—	—	—	—	—	—	54	92	131	45	77	110	39	67	94
500	—	—	—	—	—	—	—	—	—	—	—	—	—	—	—	49	83	118

3) For the purposes of Table 9.32.3.4., the furnace airflow shall be determined

a) 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

b) 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).

4) Linear interpolation is permitted in using Table 9.32.3.4.

5) An outdoor air supply duct shall be installed between the outdoors and the furnace return air plenum and shall be connected

a) not less than 3 m upstream of the plenum connection to the furnace, as measured along the length of the duct, or

b) through an acceptable mixing device installed in the return air plenum.

6) The outdoor air supply duct required by Sentence (5) shall incorporate a flow-regulating damper.

7) 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.

8) 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

a) approved by the manufacturer for the handling of untempered outdoor air if it will be handling untempered outdoor air,

b) approved by the manufacturer for continuous operation, and

c) 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.

9) The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that

a) 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,

b) where applicable, activation of the principal ventilation fan automatically activates the auxiliary outdoor air supply fan described in Sentence (8), and

c) the auxiliary outdoor air supply fan does not operate when the principal ventilation fan is not operating.

10) 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.

11) 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.

12) 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.

Ventilation Systems Not Used in Conjunction with Forced Air Heating Systems

(See Appendix A.)

1) 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.

2) 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.

3) The principal ventilation fan control required by Sentence 9.32.3.3.(5) shall be wired in such a way that

a) activation of the principal ventilation fan automatically activates the outdoor air supply fan required by Sentence (2), and

b) the outdoor air supply fan does not operate when the principal ventilation fan is not operating.

4) The outdoor air supply fan shall be connected to the outdoors through an outdoor air supply duct.

5) The outdoor air supply duct required by Sentence (4) shall incorporate a flow-regulating damper.

6) 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.

7) The airflow measurements required by Sentence (6) shall be done using a method accurate to within ±15% of the flow rate being measured.

8) 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.

9) 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.

10) 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

a) each bedroom,

b) any storey, including basements and heated crawl spaces, without a bedroom, and

c) if there is no storey without a bedroom, to the principal living area.

11) 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.

12) All branch supply ducts that are not fitted with diffusers with adjustable balance stops shall be supplied with balancing dampers that

a) can be fixed in their adjusted positions, and

b) include devices to indicate the positions of the dampers.

13) 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.

14) 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.

Principal Ventilation System Supply Air

(See Appendix A.)

1) Except as provided in Sentence (6), a principal ventilation system shall mechanically provide supply air in accordance with Sentence (2), (3), (4) or (5).

2) Where the principal ventilation system is a ducted forced-air heating system, the ducted forced-air heating system shall

a) provide supply air through the ducting to

i) each bedroom, and

ii) each floor level without a bedroom,

b) draw supply air from an outdoor inlet that is connected to the cabinet containing the furnace air circulating fan required by Clause (d) by ducting that measures, from that cabinet to the point at which the ducting intersects the return air plenum,

i) between 3 m and 4.5 m in length, or

ii) if a flow control device is used, not more than 4.5 m in length.

c) draw supply air through ducting that is

i) rigid ducting with an equivalent diameter of at least 100 mm, or

ii) flexible ducting with an equivalent diameter of at least 125 mm, and

d) have a furnace air circulating fan set to run continuously.

3) Where the principal ventilation system is a ducted forced-air heating system used in combination with a heat-recovery ventilator,

a) the ducted forced-air heating system shall conform to Clauses (2)(a), (c) and (d),

b) the heat-recovery ventilator shall draw supply air from an outdoor inlet into the return air plenum of the ducted forced-air heating system, and

c) the heat-recovery ventilator shall draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

4) Where the principal ventilation system is a heat-recovery ventilator, the heat-recovery ventilator shall

a) provide supply air through dedicated ducting to

i) each bedroom, and

ii) each floor level without a bedroom, and

b) draw exhaust air, through dedicated ducting,

i) from one or more indoor inlets, at least one of which is located at least 2 m above the floor of the uppermost floor level, and

ii) at the capacity rating of the heat-recovery ventilator, which shall be no less than the air-flow rate specified in Table 9.32.3.5.

5) Where the principal ventilation system is a ducted central-recirculation ventilation system, the ducted central-recirculation ventilation system shall

a) draw supply air from an outdoor inlet connected upstream of the fan, and

b) draw air from

i) each bedroom and deliver it to a common area, or

ii) a common area and deliver it to each bedroom.

6) A principal ventilation system need not conform to Sentence (1) if the principal ventilation system

a) services a dwelling unit that

i) is located where the January design temperature, on a 2.5% basis determined in conformance with Article 1.1.3.1., is greater than −20°C,

ii) has only 1 storey and a floor area of less than 168 m² within the building envelope (see Appendix A),

iii) does not have a ducted forced-air heating system, and

iv) except for a secondary suite, is not located in a building conforming to Subsection 9.36.6. or 10.2.3., and

b) provides supply air passively from outdoors through dedicated inlets that

i) are located in each bedroom and at least one common area,

ii) are located at least 1 800 mm above the floor, and

iii) have an unobstructed vent area of not less than 25 cm².

Exhaust-Only Ventilation Systems

(See Appendix A.)

1) A ventilation system with no provision for the introduction of outdoor air to the dwelling unit may only be used where the dwelling unit

a) 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

b) 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.

2) 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.

3) 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.

Principal Ventilation System Exhaust Fan

1) A principal ventilation system exhaust fan shall

a) run continuously, and

b) provide at least the air-flow rate specified in Table 9.32.3.5.

Table Principal Ventilation System Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.5.(1)
Floor Area, m2	Minimum Air-flow Rate, L/s
Number of Bedrooms
0–1	2–3	4–5	6–7	>7
< 140	14	21	28	35	42
140–280	21	28	35	42	49
281–420	28	35	42	49	56
421–560	35	42	49	56	64
561–700	42	49	56	64	71
> 700	49	56	64	71	78

2) For the purposes of Sentence (1), the capacity rating of the principal ventilation system exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

3) The principal ventilation system exhaust fan shall be

a) designed to run continuously, and

b) controlled by a dedicated switch that

i) has 2 settings, on and off,

ii) is located where it will be accessible for the purposes of servicing the exhaust fan but not likely to be turned off inadvertently, and

iii) is clearly marked “PRINCIPAL VENTILATION EXHAUST FAN.”

4) If the principal ventilation system exhaust fan is designed to run at multiple air-flow rates,

a) the air-flow rate of the fan shall be controlled by a switch other than the switch described in Clause (3)(b), and

b) the lowest air-flow rate shall not be less than the air-flow rate specified in Table 9.32.3.5.

5) The sound rating of the principal ventilation system exhaust fan shall not exceed 1.0 sone when running continuously at the air-flow rate specified in Table 9.32.3.5. as determined in accordance with

a) HVI Publication 915, “Loudness Testing and Rating Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Supplemental Exhaust

(See Appendix A.)

1) 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.

2) 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.

3) A supplemental exhaust fan is not required in a kitchen where the principal ventilation fan draws from that kitchen and other rooms, provided

a) 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

b) the high exhaust rate of the principal ventilation fan, as described in Clause (a), is activated by a manual switch in the kitchen labelled “KITCHEN EXHAUST.”

4) 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.

5) 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.

6) A supplemental exhaust fan required by this Article shall be controlled by a manual switch located in the room served by the fan.

7) 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).

8) 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.

Kitchen and Bathroom Exhaust Fans

1) An exhaust fan that provides at least the air-flow rate specified in Table 9.32.3.6. shall be installed in

a) every kitchen, and

b) every bathroom or water-closet room, unless the bathroom or water-closet room is served by the principal ventilation system exhaust fan that complies with Article 9.32.3.5.

2) For the purposes of Sentence (1), the capacity rating of the exhaust fan shall be determined, based on air-flow performance at 50 pa of external static pressure, in accordance with

a) HVI Publication 916, “Airflow Test Procedure,” or

b) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment.”

Table Kitchen/Bathroom Exhaust Fan Minimum Air-flow Rate Forming part of Sentence 9.32.3.6.(1)
Room	Minimum Exhaust Fan Air-flow Rate, L/s
Intermittent	Continuous
Kitchen	47	N/A
Bathroom	23	9

Protection Against Depressurization

(See Appendix A.)

1) This Article applies to

a) 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

b) 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.

2) 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

a) not less than the exhaust capacity of the device, and

b) not greater than that exhaust capacity plus 10%.

3) 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.

4) The outdoor makeup air required by Sentence (2) shall be

a) introduced to a normally unoccupied area in the dwelling unit, or

b) tempered to at least 12°C before being introduced to occupied areas or to a supply duct system.

5) 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.

6) 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.

7) 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, “The Spillage Test: Method to Determine the Potential for Pressure-Induced Spillage from Vented, Fuel-Fired, Space Heating Applicances, Water Heaters and Fireplaces,” 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.

8) 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.

Heated Crawl Space Ventilation

1) Where a crawl space is heated by a ducted forced-air heating system that does not draw air from the crawl space to the furnace through the return air plenum, the crawl space shall be connected to the floor space above the crawl space by at least one air-transfer grille.

2) Where a crawl space is heated other than by a ducted forced-air heating system, the crawl space shall

a) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the principal ventilation system by a supply air outlet or an exhaust air inlet,

b) be connected to the floor space above the crawl space by at least 2 air-transfer grilles, or

c) be connected to

i) the floor space above the crawl space by at least one air-transfer grille, and

ii) the outdoors by a dedicated exhaust fan that complies with Sentence (4).

3) An air-transfer grille required by Sentence (1) or (2) shall have an unobstructed vent area of the greater of

a) 25 cm², and

b) 0.83 cm² for every m² of crawl space area.

4) Where a dedicated exhaust fan is installed in accordance with Subclause (2)(c)(ii), the dedicated exhaust fan shall

a) provide an air-flow rate of at least 23 L/s, and

b) be controlled by

i) a humidity control device, or

ii) an adjustable time control device that is capable of providing not less than 8 total hours of ventilation per 24 hour period.

5) Where a crawl space is divided into 2 or more compartments, each heated compartment shall conform to Sentence (1) or (2).

Carbon Monoxide Alarms

(See Appendix A.)

1) This Article applies to every building that contains a residential occupancy and that also contains

a) a fuel-burning appliance, or

b) a storage garage.

2) Carbon monoxide (CO) alarms required by this Article shall

a) conform to CAN/CSA-6.19, “Residential Carbon Monoxide Alarming Devices,”

b) be equipped with an integral alarm that satisfies the audibility requirements of CAN/CSA-6.19, “Residential Carbon Monoxide Alarming Devices,”

c) 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

d) be mechanically fixed at a height recommended by the manufacturer.

3) 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

a) at the manufacturer’s recommended height where these instructions specifically mention solid-fuel-burning appliances, or

b) in the absence of specific instructions related to solid-fuel-burning appliances, on or near the ceiling.

4) Where a fuel-burning appliance is installed in a suite of residential occupancy, a CO alarm shall be installed

a) inside each bedroom, or

b) outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.

5) 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

a) 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

b) in the service room.

6) 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

a) inside each bedroom, or

b) outside each bedroom, within 5 m of each bedroom door, measured following corridors and doorways.

Fans

(See Appendix A.)

1) Except as provided in Sentence (4), capacity ratings for required fans shall be determined in accordance with

a) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment,” or

b) HVI 916, “Airflow Test Standard.”

2) Sound ratings for fans shall be determined in accordance with

a) CAN/CSA-C260-M, “Rating the Performance of Residential Mechanical Ventilating Equipment,” or

b) HVI 915, “Procedure for Loudness Rating of Residential Fan Products.”

3) Capacity ratings for fans shall be measured at the external static pressure differentials shown in Table 9.32.3.10.A.

4) 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.”

Table Minimum External Static Pressure Differential for Rating of Fans Forming part of Sentence 9.32.3.10.(3)
Fan Configuration or Application	Minimum External Static Pressure Differential to be Used in Determining Rated Capacity
Fans installed with ducts connected on both sides, any application	100 Pa (0.4 inch water column)
Fans installed with ducts on one side only, used as the principal ventilation fan in exhaust-only systems permitted by Article 9.32.3.6.	62 Pa (0.25 inch water column)
Other required fans	25 Pa (0.1 inch water column)

5) 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.

6) 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.

Table Maximum Sound Rating for Fans Forming part of Sentence 9.32.3.10.(6)
Fan Application	Maximum Sound Rating, sones
	Rated according to CAN/CSA-C260-M	Rated according to HVI 915
Principal ventilation fan	2.0	2.5
Supplemental fans installed in bathrooms and their makeup air fans	2.5	3.5
Supplemental fans installed in kitchens and their makeup air fans	No rating required	No rating required

7) Mechanical ventilation devices shall conform to CSA C22.2 No. 113-M, “Fans and Ventilators.”

Air Ducts

1) Exhaust ducts shall discharge to the outdoors.

2) Exhaust ducts that are downstream of an exhaust fan shall have no connections to other fans or ducts.

3) Exhaust ducts, and supply ducts that conduct heated or cooled air, shall

a) be sized in accordance with the requirements of the manufacturer of the fans to which they are connected, and

b) have an equivalent diameter not less than that specified by Table 9.32.3.8.(3).

Table Maximum Equivalent Duct Length(1), m Forming part of Sentence 9.32.3.8.(3)
Flexible Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
125 (123)	32	15	—	—	—	—
150 (177)	46	40	28	18	13	—
175 (240)	46	46	46	46	46	24
200 (314)	46	46	46	46	46	46
Rigid Duct
Equivalent Diameter, mm (Cross Section Area for Rectangular Ducts, cm2)	Fan Capacity, L/s
25	40	50	60	70	80
100 (79)	32	15	—	—	—	—
125 (123)	46	40	28	18	13	—
150 (177)	46	46	46	42	34	24
175 (240)	46	46	46	46	46	46

Notes to Table 9.32.3.8.(3):
(1)	The equivalent length of a duct is the length of the duct plus 10 m for the exterior hood and 3 m for each 90° elbow.

4) Where an exhaust duct passes through or is located adjacent to a space that is not conditioned space, the duct shall conform to Article 9.32.3.2., except that in no case shall such a duct be insulated to less than RSI 0.75.

5) Where a principal ventilation system supply duct passes through or is located adjacent to a conditioned space, the duct shall be

a) insulated to not less than RSI 0.75, and

b) provided with an effective vapour barrier.

6) Where a kitchen exhaust fan grille is installed within 1.2 m horizontally of a cooktop, the exhaust fan duct shall

a) be constructed of a material that is noncombustible, corrosion-resistant, and cleanable, and

b) be equipped with a grease filter at the intake end.

7) Except for a supply air system described in Sentence 9.32.3.4.(2) or (3) , all joints in exhaust ducts, and in supply ducts that conduct conditioned air, shall be sealed against air leakage with

a) sealants or gaskets made from liquids, mastics or heat-applied materials,

b) mastic with embedded fabric,

c) foil-faced butyl tape, or

d) aluminum foil tape.

8) Supply ducts for a mechanical ventilation system shall not be used to provide combustion or dilution air to fuel-burning appliances.

Ducts

(See Appendix A.)

1) 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.

2) Exhaust ducts shall not discharge into heated or unheated enclosed spaces.

3) 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.

4) 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.

5) All exhaust intakes located within 3 m horizontally of a cooktop shall be equipped with a grease filter at the intake end.

6) Ductwork for cooking appliance exhaust fans shall

a) be of noncombustible, corrosion-resistant material,

b) lead directly to the outdoors with no connections to other exhaust fans or ducts, and

c) be equipped with a grease filter at the intake end.

7) All ductwork shall be installed to avoid crushing and shall be permanently supported to prevent sagging.

8) Joints in all ventilation system ducting shall be sealed with mastic, metal foil duct tape or the manufacturers' specified sealants.

9) 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 Equivalent Duct Sizes Forming part of Sentence 9.32.3.11.(9)
Fan's External Static Pressure, Pa	Duct Diameter, mm	Maximum Airflow in Duct, L/s
		7	15	25	35	50	75	100
		Maximum Length of Duct, m
25	75	6	1	0	0	0	0	0
	100	25	6	2	1	0	0	0
	125	60	17	6	3	1	0	0
	150	60	42	16	8	4	2	1
	175	60	60	34	18	9	4	2
	200	60	60	60	35	18	8	5
50	75	16	4	1	0	0	0	0
	100	60	16	6	3	1	0	0
	125	60	47	18	9	5	2	1
	150	60	60	44	23	12	5	3
	175	60	60	60	49	25	12	7
	200	60	60	60	60	48	22	13
62.5	75	22	5	2	1	0	0	0
	100	60	21	8	4	2	1	0
	125	60	60	24	12	6	3	1
	150	60	60	58	31	15	7	4
	175	60	60	60	60	33	15	9
	200	60	60	60	60	60	29	17
100	75	38	9	3	1	0	0	0
	100	60	36	14	7	3	1	1
	125	60	60	41	22	11	5	3
	150	60	60	60	53	27	12	7
	175	60	60	60	60	57	27	15
	200	60	60	60	60	60	51	30
150	75	59	14	5	2	1	0	0
	100	60	57	22	11	6	2	1
	125	60	60	60	34	17	8	4
	150	60	60	60	60	42	20	11
	175	60	60	60	60	60	42	24
	200	60	60	60	60	60	60	46

10) In using Table 9.32.3.11.A.,

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,

b) 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,

c) outdoor air supply ducts shall be sized as trunk ducts,

d) “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

e) “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.

11) 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.

12) Where rectangular duct is used in place of round duct, it shall be selected according to Table 9.32.3.11.B.

Table Equivalent Duct Sizes Forming part of Sentences 9.32.3.11.(9) and (12)
Required Round Duct Size, mm (in.)	Permitted Equivalent Rectangular Duct Size, mm (in.)
	Stack duct	100 mm (4 in.) depth	125 mm (5 in.) depth	150 mm (6 in.) depth
75 (3)	75 x 150 (3 x 6)	50 x 100 (2 x 4)	—	—
100 (4)	75 x 250 (3 x 10)	75 x 100 (3 x 4)	75 x 125 (3 x 5)	75 x 150 (3 x 6)
125 (5)	75 x 250 (3 x 10)	125 x 100 (5 x 4)	100 x 125 (4 x 5)	100 x 150 (4 x 6)
150 (6)	75 x 300 (3 x 14)	200 x 100 (8 x 4)	150 x 125 (6 x 5)	125 x 150 (5 x 6)
175 (7)	75 x 350 (3 x 14)	275 x 100 (11 x 4)	200 x 125 (8 x 5)	175 x 150 (7 x 6)
> 175 (> 7)	design to Subsection 9.33.4.

Outdoor Inlets and Outlets

1) Outdoor air inlets and exhaust outlets shall be shielded from the weather, birds and rodents by using hoods incorporating a screen of corrosion-resistant material with openings of 6 to 12 mm.

Heat Recovery Ventilators

(See Appendix A.)

1) This Article shall apply to heat recovery ventilators installed to provide one or more of the fans required by this Subsection.

2) 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.

3) Two or more heat recovery ventilators shall not be connected in parallel airflow to a common downstream exhaust duct.

4) All start-up procedures recommended by the manufacturer, including air balancing and airflow determination, shall be followed.

5) 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.

6) 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.

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 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.

4) Air intakes shall be clearly labeled as such for identification from locations outside the dwelling unit.

5) 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.

6) 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.

7) Air intake openings shall incorporate screens or grilles to protect against the entry of animals and insects.

8) Except for exhaust outlets serving heat recovery ventilators, exhaust outlets shall incorporate backdraft dampers.

9) 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.

10) Screens, grilles and filters installed in air intake and exhaust openings shall be easily removable for cleaning purposes, without the need for special tools.

11) 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.

12) Screens and grilles shall be of corrosion-resistant material.

Table Area of Openings with Screens or Grilles Forming part of Sentence 9.32.3.13.(11)
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

Interior Distribution

1) Interior doors shall be undercut by a minimum of 12 mm above the finished floor or the rooms shall be provided with an air-transfer grille with an unobstructed vent area that is not less than 100 cm².