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The British Columbia Building Code | Section 6.3. | Ventilation Systems Pt 2

Division B: Acceptable Solutions Part 6 – Heating, Ventilating and Air-conditioning
British Columbia Building Code 2018 Revision 2.01 Division B
Section 6.3. Ventilation Systems
6.3.1. Ventilation
6.3.1.1. Required Ventilation
1) Except as provided in Sentence(3), all buildings shall be ventilated in accordance with this Part.
2) Except in storage garages covered by Article6.3.1.4., the rates at which outdoor air is supplied in buildings by
ventilation systems shall be not less than the rates required by ANSI/ASHRAE 62, “Ventilation for Acceptable
Indoor Air Quality” (except Addendum n).
3) Self-contained heating-season mechanical ventilation systems serving only one dwelling unit shall
comply with
a) this Part, or
b) Subsection9.32.3.
4) For suites in buildings conforming to Subsection 9.36.6. or 10.2.3., the outdoor air required by Sentence (2)
shall be supplied directly to each suite by mechanical ventilation through ducting.
(See Note
A-6.3.1.1.(4).)
6.3.1.2. Crawl Spaces and Attic or Roof Spaces
1) Unconditioned and unoccupied crawl spaces and unconditioned and unoccupied attic or roof spaces shall be
ventilated by natural or mechanical means as required by Part5. (See NoteA-6.3.1.2.(1).)
6.3.1.3. Natural Ventilation
1) Except as permitted by Sentence(2) and except as required by Sentence 6.3.1.1.(4), the ventilation required
by Article6.3.1.1. shall be provided by mechanical ventilation, except that it can be provided by natural ventilation
or a combination of natural and mechanical ventilation in
a) buildings of other than residential occupancy having an occupant load of not more than one person per 40m
2
during normal use,
b) buildings of industrial occupancy where the nature of the processes contained therein permits or requires the
use of large openings in the building envelope even during the winter, and
c) seasonal buildings not intended to be occupied during the winter.
2) Where climatic conditions permit, buildings containing occupancies other than residential occupancies may be
ventilated by natural ventilation methods in lieu of mechanical ventilation where engineering data demonstrates that
such a method will provide the required ventilation for the type of occupancy.
6.3.1.4. Ventilation of Storage Garages
1) Except as provided in Sentences(4) and(6), an enclosed storage garage for five or more motor vehicles shall
have a mechanical ventilation system designed to
a) limit the concentration of carbon monoxide to not more than 100parts per million parts of air,
b) limit the concentration of nitrogen dioxide to not more than 3parts per million parts of air, where the
majority of the vehicles stored are powered by diesel-fuelled engines, or
c) provide, during operating hours, a continuous supply of outdoor air at a rate of not less than 3.9L/s for each
square metre of floor area (see Article3.3.1.20.).
(See also Sentence3.3.5.4.(4).) (See NoteA-6.3.1.4.(1).)
2) Mechanical ventilation systems provided in accordance with Clause(1)(a) shall be controlled by carbon
monoxide monitoring devices, and systems provided in accordance with Clause(1)(b) shall be controlled by nitrogen
dioxide or other acceptable monitoring devices. (See NoteA-6.3.1.4.(2).)
3) Mechanical ventilation systems provided in accordance with Sentence(1) shall be designed such that the
pressure in the storage garage is less than the pressure in adjoining buildings of other occupancy, or in adjacent portions
of the same building having a different occupancy.
Part 6 – Heating, Ventilating and Air-conditioning Division B: Acceptable Solutions
Division B Revision 2.01 British Columbia Building Code 2018
4) In storage garages subject to the requirements of Sentences(1) and(2), where motor vehicles are parked by
mechanical means, the ventilation requirements may be reduced by one half.
5) Except as provided in Sentence(6), ticket and attendant booths of storage garages shall be pressurized with a
supply of uncontaminated air.
6) The requirements of Sentences(1) to(5) shall not apply to open-air storeys in a storage garage.
6.3.1.5. Heat Recovery Ventilators
1) Heat recovery ventilators with rated capacities of not less than 25L/s and not more than 200L/s shall be
installed in accordance with Subsection9.32.3.
6.3.1.6. Indoor Air Contaminants
(See NoteA-6.3.1.6.)
1) Air contaminants of concern that are released within buildings shall
a) be removed insofar as is possible at their points of origin, and
b) not be permitted to accumulate in concentrations greater than those permitted by applicable provincial or
territorial requirements or, in the absence of such requirements, by good engineering practice such as that
described in the publications listed in Sentence6.2.1.1.(1), measured using the methodology
described therein.
2) Systems serving spaces that contain sources of contamination and systems serving other occupied parts of the
building but located in or running through spaces that contain sources of contamination shall be designed in such a
manner as to prevent the spread of such contamination to other occupied parts of the building.
3) Heating, ventilating and air-conditioning systems shall be designed to minimize the growth and spread of
bio-contaminants.
6.3.1.7. Commercial Cooking Equipment
1) Except as provided in Article3.6.3.5., systems for the ventilation of commercial cooking equipment shall be
designed, constructed and installed to conform to NFPA96, “Ventilation Control and Fire Protection of
Commercial Cooking Operations.”
6.3.2. Air Duct Systems
6.3.2.1. Application
1) This Subsection applies to the design, construction and installation of air duct distribution systems serving
heating, ventilating and air-conditioning systems other than those in dwelling units covered by Part9.
6.3.2.2. Drain Pans
1) Dehumidifying cooling coil assemblies and condensate-producing heat exchangers shall be equipped with
drain pans beneath them that are
a) designed in accordance with Section 5.11, Drain Pans, of ANSI/ASHRAE 62.1, “Ventilation for Acceptable
Indoor Air Quality,”
b) provided with an outlet that is piped to the outside of the airstream in a location where condensate can be
eliminated, and
c) installed so that water drains freely from the pan.
6.3.2.3. Materials in Air Duct Systems
1) All ducts, duct connectors, associated fittings and plenums used in air duct systems shall be constructed of
materials as described in Article3.6.5.1.
2) Ducts that are used in a location where they may be subjected to excessive moisture shall have no appreciable
loss of strength when wet and shall be resistant to moisture-induced corrosion.
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British Columbia Building Code 2018 Revision 2.01 Division B
3) All ductwork and fittings shall be constructed and installed as recommended in SMACNA Manuals and
ASHRAE Standards.
4) All duct materials shall be suitable for exposure to the temperature and humidity of the air being carried and
shall be resistant to corrosion caused by contaminants in the air being conveyed in the duct.
6.3.2.4. Connections in Air Duct Systems
1) Air duct systems shall have tight-fitting connections throughout.
6.3.2.5. Duct Coverings and Linings
(See NoteA-6.3.2.5.)
1) Coverings, linings and associated adhesives and insulation used in air ducts, plenums and other parts of air
duct systems shall comply with Article3.6.5.4.
2) Duct linings shall be installed so that they will not interfere with the operation of volume or balancing
dampers or of fire dampers, fire stop flaps and other closures.
6.3.2.6. Clearance of Ducts and Plenums
1) The clearance of ducts and plenums from combustible materials shall comply with Article3.6.5.6.
6.3.2.7. Interconnection of Systems
1) In a care or residential occupancy, air from one suite shall not be circulated to any other suite or to a public
corridor.
2) Except as permitted by Sentences(3) and6.3.2.10.(6), air duct systems serving storage garages shall not be
directly interconnected with other parts of the building.
3) Exhaust ducts referred to in Sentence6.3.2.10.(10) are permitted to exhaust through an enclosed storage
garage prior to exhausting to the outdoors, provided
a) the storage garage’s exhaust system runs continuously,
b) the capacity of the storage garage’s exhaust system is equal to or exceeds the volume of the exhaust entering the
garage, and
c) a leakage rate 1 smoke/fire damper rated in accordance with CAN/ULC-S112.1, “Leakage Rated Dampers for
Use in Smoke Control Systems,” is provided near the duct outlet location in the storage garage to prevent air
from the storage garage from entering the exhaust ductwork system in the event the building’s exhaust fan is
shut down.
6.3.2.8. Makeup Air
(See NoteA-6.2.1.1.)
1) In ventilating systems that exhaust air to the outdoors, provision shall be made for the admission of a supply
of makeup air in sufficient quantity so that the operation of the exhaust system and other exhaust equipment or
combustion equipment is not adversely affected.
2) Makeup air facilities required by Sentence(1) shall be interlocked with the exhaust devices they serve so that
both operate together.
3) Where makeup air facilities are intended to introduce air directly from the outdoors to occupied parts of the
building in winter, they shall incorporate means of tempering that air to maintain the indoor design temperature.
6.3.2.9. Supply, Return, Intake and Exhaust Air Openings
1) Supply, return and exhaust air openings located less than 2m above the floor in rooms or spaces in buildings
shall be protected by grilles having openings of a size that will not allow the passage of a 15mm diam sphere.
2) Outdoor air intakes shall be located so that
a) reserved
, and
b) they are separated a minimum distance from sources of contaminants in accordance with Table6.3.2.9.
Part 6 – Heating, Ventilating and Air-conditioning Division B: Acceptable Solutions
Division B Revision 2.01 British Columbia Building Code 2018
3) Outdoor air intakes shall be installed not less than 0.3m above roofs, landscape grades or other surfaces,
taking into account anticipated snow accumulation levels.
4) Exterior openings for outdoor air intakes and exhaust outlets shall be shielded from the entry of snow and
rain and shall be fitted with corrosion-resistant screens of mesh having openings not larger than 15mm, except where
experience has shown that climatic conditions require larger openings to prevent the screen openings from icing over.
5) Screens required in Sentence(4) shall be accessible for maintenance.
6) Combustible grilles, diffusers and other devices covering supply, return, intake and exhaust openings shall
comply with Article3.6.5.7.
6.3.2.10. Exhaust Ducts and Outlets
1) Except as provided in Sentence(2), exhaust ducts of non-mechanical ventilating systems serving separate
rooms or spaces shall not be combined.
2) Exhaust ducts of non-mechanical ventilating systems serving similar occupancies may be combined
immediately below the point of final delivery to the outdoors, such as at the base of a roof ventilator.
3) Exhaust ducts of ventilating systems shall have provision for the removal of condensation where this may be
aproblem.
4) Exhaust outlets shall be designed to prevent backdraft under wind conditions.
5) Except as permitted in Sentence(6), exhaust systems shall discharge directly to the outdoors. (See
NoteA-6.3.2.10.(5) and (6).)
6) Exhaust systems are permitted to exhaust into a storage garage, provided
a) they serve rooms that are accessible only from that storage garage,
b) the exhaust contains no contaminants that would adversely affect the air quality in the storage garage
(see NoteA-6.3.2.10.(6)(b)), and
c) they are designed in accordance with Sentence6.3.2.7.(3).
(See NoteA-6.3.2.10.(5) and (6).)
7) Exhaust ducts connected to laundry-drying equipment shall be
a) independent of other exhaust ducts,
b) accessible for inspection and cleaning, and
c) constructed of a smooth corrosion-resistant material.
(See NoteA-6.3.2.10.(7) and (8).)
Table 6.3.2.9.
Minimum Distances of Air Intakes from Sources of Contaminants
Forming Part of Sentence 6.3.2.9.(2)
Source of Contaminants Minimum Distance of Outdoor Air Intake, m
Garage entry of a garage for 5 or more motor vehicles, automobile loading area and
drive-in queue
4.5
Truck loading area or dock, and bus parking 7.6
Driveway, street, and parking space 1.5
Thoroughfare, arterial road, freeway, and highway 7.6
Garbage storage/pick-up area and dumpsters 4.5
Discharge from evaporative cooling tower, evaporative fluid cooler and evaporative
condenser
7.6
Sanitary vent 3.5
Kitchen cooking exhaust 3.0
Vent for combustion products 3.0
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8) Where collective venting of multiple installations of laundry-drying equipment is used, the ventilation
system shall
a) be connected to a common exhaust duct that is vented by one central exhaust fan and incorporates one central
lint trap,
b) include an interlock to activate the central exhaust fan when laundry-drying equipment is in use, and
c) be provided with make-up air.
(See NoteA-6.3.2.10.(7) and (8).)
9) Exhaust ducts or vents connected to laundry-drying equipment shall discharge directly to the outdoors.
10) Except as provided in Sentence(12) and except for self-contained systems serving individual dwelling units,
exhaust ducts serving rooms containing water closets, urinals, basins, showers or slop sinks shall be independent of
other exhaust ducts.
11) Except as provided in Sentence(12) and except for self-contained systems serving individual dwelling units,
exhaust ducts serving rooms containing residential cooking equipment shall be independent of other exhaust ducts.
12) Two or more exhaust systems described in Sentences(10) and(11) may be interconnected or connected with
exhaust ducts serving other areas of the building, provided
a) the connections are made at the inlet of an exhaust fan, and all interconnected systems are equipped with
suitable back pressure devices to prevent the passage of odours from one system to another when the fan is
not in operation, or
b) the exhaust ducts discharge to a shaft that is served by an exhaust fan having a capacity that is equal to or
greater than the combined capacity of the exhaust fans discharging to the plenum multiplied by the operation
diversity factor, provided that the exhaust fan serving the shaft operates continuously (see
NoteA-6.3.2.10.(12)(b)).
13) Where exhaust ducts containing air from conditioned spaces pass through or are adjacent to unconditioned
spaces, the ducts shall be constructed to prevent condensation from forming on the inside or outside of the ducts.
6.3.2.11. Return-Air System
1) Return-air systems shall comply with Article3.6.5.8.
2) Where a ceiling space is used as a return-air plenum, the requirements of Article3.6.4.3. shall apply.
3) A public corridor or exit shall not be used as a return-air plenum.
6.3.2.12. Underground Ducts
1) Underground ducts shall
a) be constructed and installed to provide interior drainage from and access to all low points,
b) not be connected directly to a sewer, and
c) be installed and constructed of materials recommended by ASHRAE and SMACNA Standards and HRAI
Manuals.
2) A clean-out or pump-out connection shall be provided in an underground duct system at every low point of
the duct system.
6.3.2.13. Filters
1) Air filters for air duct systems shall conform to the requirements for Class2 air filter units as described in
CAN/ULC-S111, “Fire Tests for Air Filter Units.”
2) When electrostatic-type filters are used, they shall be installed so as to ensure that the electric circuit is
automatically de-energized when filter access doors are opened or, in dwelling units, when the furnace circulation fan
is not operating.
6.3.2.14. Reserved
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6.3.2.15. Evaporative Cooling Towers, Evaporative Fluid Coolers and
Evaporative Condensers
1) Discharge from evaporative cooling towers to ventilation air intakes shall comply with
a) Sentence6.3.2.9.(2), and
b) CAN/CSA-Z317.2, “Special Requirements for Heating, Ventilation, and Air-Conditioning (HVAC)
Systems in Health Care Facilities.”
2) The distance between the air intakes of evaporative cooling towers, evaporative fluid coolers and evaporative
condensers in relation to kitchen exhaust outlets, vegetation or other sources of organic matter shall be not less
than 4.6m.
3) Make-up water connections shall be equipped with backflow prevention devices that conform to
Article2.6.2.1. of DivisionB of the Book II, (Plumbing Systems), of this code
.
4) Water treatment equipment for biological growth control shall be provided in accordance with
Sub-Section7.6.2. of ASHRAE Guideline12, “Minimizing the Risk of Legionellosis Associated with Building
Water Systems.”
5) Drains, overflows and blow-downs shall be connected to the building’s drainage system in accordance with
Clause2.4.2.1.(1)(e) of DivisionB of the Book II, (Plumbing Systems), of this code
.
6) Evaporative cooling towers, evaporative fluid coolers and evaporative condensers shall be provided with access
ports, service platforms, fixed ladders and restraint connections to allow visual inspection, maintenance and testing.
6.3.2.16. Evaporative Air Coolers, Misters, Atomizers, Air Washers and Humidifiers
1) The filter and water evaporation medium of every air washer and evaporative air cooler enclosed within a
building shall be made of noncombustible material.
2) Sumps for air washers and evaporative air coolers shall be constructed and installed so that they can be flushed
and drained.
3) Evaporative air coolers, misters, atomizers, air washers and humidifiers shall be designed in accordance with
Sections8 and 9 of ASHRAE Guideline 12, “Minimizing the Risk of Legionellosis Associated with Building
Water Systems.”
6.3.2.17. Fans and Associated Air-Handling Equipment
1) Fans for heating, ventilating and air-conditioning systems shall be located and installed so that their operation
a) does not adversely affect the draft required for proper operation of fuel-fired appliances, and
b) does not allow the air in the duct system to be contaminated by air or gases from the boiler room or
furnace room.
2) Fans and associated air-handling equipment, such as air washers, filters and heating and cooling units, when
installed on the roof or elsewhere outside the building, shall be of a type designed for outdoor use.
6.3.2.18. Vibration Isolation Connectors
1) Vibration isolation connectors in air duct systems shall comply with Article3.6.5.2.
6.3.2.19. Tape
1) Tape used for sealing joints in air ducts, plenums and other parts of air duct systems shall comply with
Article3.6.5.3.
6.3.3. Chimneys and Venting Equipment
6.3.3.1. Requirement for Venting
1) Except as provided in Articles6.3.3.2. and6.3.3.3., the products of combustion from oil-, gas- and
solid-fuel-burning appliances shall be vented in conformance with the requirements in the applicable appliance
installation standard listed in Article6.2.1.5.
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2) Except as provided in Article6.2.1.5., vented products of combustion, other than those referred to in
Sentence(1), shall be discharged away from the building, so as not to re-enter it, to a distance not less than
a) 2.15m above sidewalks and driveways,
b) 3m from outdoor air intakes,
c) 3m horizontally or vertically from doors and operable windows, and
d) 3m horizontally or vertically from occupiable outdoor spaces, excluding maintenance spaces.
(See NoteA-6.3.3.1.(2).)
6.3.3.2. Masonry or Concrete Chimneys
1) Rectangular masonry or concrete chimneys not more than 12m in height shall conform to Part9 if they serve
a) appliances with a combined total rated heat output of 120kW or less, or
b) fireplaces.
2) Masonry or concrete chimneys other than those described in Sentence(1) shall be designed and installed in
conformance with the appropriate requirements in NFPA211, “Chimneys, Fireplaces, Vents, and Solid
Fuel-Burning Appliances.”
6.3.3.3. Metal Smoke Stacks
1) Single wall metal smoke stacks shall be designed and installed in conformance with NFPA211, “Chimneys,
Fireplaces, Vents, and Solid Fuel-Burning Appliances.”
6.3.3.4. Access Ladders
1) Access ladders for chimneys, when provided, shall consist of steel or bronze rungs, built into the walls of the
chimneys.
2) Rungs for external ladders shall begin at not less than 2.5m from ground level.
6.3.4. Ventilation for Laboratories
6.3.4.1. Application
1) This Subsection applies to laboratories where dangerous goods, including flammable liquids and combustible
liquids, are used in normal laboratory operations in quantities or in a manner that creates a fire or explosion hazard.
6.3.4.2. General Ventilation
1) A laboratory shall be provided with continuous mechanical ventilation designed to ensure that dangerous
goods vapours and particles
a) do not accumulate in the laboratory,
b) are prevented from migrating to other parts of the building,
c) do not accumulate in the ventilation system,
d) are exhausted to the outdoors, and
e) are not returned to the building.
2) A ventilation system required by this Subsection shall be provided with monitoring devices to
a) indicate that the ventilation system is in operation, and
b) sound an alarm if the ventilation system is malfunctioning.
3) A ventilation system required by this Subsection shall be maintained in conformance with Article5.5.4.1. of
DivisionB of the British Columbia Fire Code.
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6.3.4.3. Enclosure Exhaust Ventilation
1) The ventilation system for a power-ventilated enclosure required by Sentence5.5.4.2.(1) of DivisionB of the
British Columbia Fire Code shall
a) conform to NFPA91, “Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible
Particulate Solids,”
b) provide continuous exhaust ventilation at an air velocity sufficient to prevent the accumulation of combustible
or reactive deposits in the power-ventilated enclosure and its exhaust duct system,
c) confine dangerous goods vapours and particles to the area where they are generated and exhaust them to the
outdoors,
d) not return the exhausted air to the building, and
e) be provided with well identified control switches that are
i) located outside of the power-ventilated enclosure, and
ii) readily accessible in case of an emergency.
6.3.4.4. Enclosure Construction
1) The power-ventilated enclosure required by Sentence 5.5.4.2.(1) of DivisionB of the British Columbia Fire
Code and its exhaust duct system shall
a) except as provided in Sentences(2) and(3), be constructed of noncombustible materials compatible with and
chemically resistant to the dangerous goods vapours and particles being exhausted, and
b) be provided with access doors to permit inspection and maintenance of the fan assembly and exhaust ducts.
2) Combustible materials are permitted in systems described in Clause(1)(a) if
a) such materials are required by the corrosive or reactive properties of the dangerous goods being used, and
b) their flame-spread rating is not more than 25.
3) The flame-spread rating required by Sentence(2) is permitted to be greater than 25 if an automatic fire
suppression system is provided inside the power-ventilated enclosure and its exhaust duct system.
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6.3.4.3. Enclosure Exhaust Ventilation
1) The ventilation system for a power-ventilated enclosure required by Sentence5.5.4.2.(1) of DivisionB of the
British Columbia Fire Code shall
a) conform to NFPA91, “Exhaust Systems for Air Conveying of Vapors, Gases, Mists, and Noncombustible
Particulate Solids,”
b) provide continuous exhaust ventilation at an air velocity sufficient to prevent the accumulation of combustible
or reactive deposits in the power-ventilated enclosure and its exhaust duct system,
c) confine dangerous goods vapours and particles to the area where they are generated and exhaust them to the
outdoors,
d) not return the exhausted air to the building, and
e) be provided with well identified control switches that are
i) located outside of the power-ventilated enclosure, and
ii) readily accessible in case of an emergency.
6.3.4.4. Enclosure Construction
1) The power-ventilated enclosure required by Sentence 5.5.4.2.(1) of DivisionB of the British Columbia Fire
Code and its exhaust duct system shall
a) except as provided in Sentences(2) and(3), be constructed of noncombustible materials compatible with and
chemically resistant to the dangerous goods vapours and particles being exhausted, and
b) be provided with access doors to permit inspection and maintenance of the fan assembly and exhaust ducts.
2) Combustible materials are permitted in systems described in Clause(1)(a) if
a) such materials are required by the corrosive or reactive properties of the dangerous goods being used, and
b) their flame-spread rating is not more than 25.
3) The flame-spread rating required by Sentence(2) is permitted to be greater than 25 if an automatic fire
suppression system is provided inside the power-ventilated enclosure and its exhaust duct system.