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Broan Automatic Make-Up Air Damper Product Guide – 04-17-13
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Direct-vented appliance: a fuel-burning appliance with a sealed combustion system that draws
all air for combustion from the outside atmosphere and discharges all flue gases to the outside
atmosphere. Also known as a sealed combustion appliance.
all air for combustion from the outside atmosphere and discharges all flue gases to the outside
atmosphere. Also known as a sealed combustion appliance.
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Exhaust system: one or more fans that remove air from the building, causing outdoor air to enter
by openings in the building shell. These openings can be specifically designed passive inlets or
make-up air dampers, or random cracks and gaps in the building envelope such as those
typically found around windows, doors, and other features.
Home leakage rate to outside: the total building leakage rate determined by a blower door at a
pressure of 50 Pa. Typical new home construction falls between 3 and 7.5 Air Changes per
Hour at 50 Pa (ACH 50). At lower leakage rates, less make-up air is provided by leakage
through the building envelope in response to exhaust fan operation within the home, and more
make-up air must be introduced through the make-up air damper duct.
Infiltration: uncontrolled inward air leakage to conditioned spaces through unintentional
openings in ceilings, floors, and walls from unconditioned spaces or the outdoors caused by
pressure differences across these openings due to wind, inside-outside temperature differences
(stack effect), and imbalances between supply and exhaust airflow rates.
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Make-up air: outdoor air and transfer air intended to replace exhaust air
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. Make-up air may enter
the home through an outdoor air duct with a damper, which is open when make-up air is needed
and closed at other times. Make-up air may also enter the home through air inlets built into the
home’s envelope or by infiltration through random cracks and gaps in the building envelope.
Make-up air damper: a general category of damper which opens to provide make-up air to a
building’s indoor environment. Such dampers may open and close based on the ambient air
pressure with respect to outdoors, or in response to an electrical signal from a controller or
another piece of HVAC equipment. Other make-up air dampers may be permanently kept open,
so there is always an open pathway between indoors and outside. In the case of the Broan
Automatic Make-Up Air Damper, this device opens in response to an electrical signal from a
compatible Broan exhaust device or from a universal pressure switch kit.
Nominal rated flow: the exhaust appliance’s rated flow at a static pressure of 0.1 in w.g. (25 Pa)
Outdoor air: air that enters a building through a ventilation system, through intentional openings
for natural ventilation, or by infiltration.
and closed at other times. Make-up air may also enter the home through air inlets built into the
home’s envelope or by infiltration through random cracks and gaps in the building envelope.
Make-up air damper: a general category of damper which opens to provide make-up air to a
building’s indoor environment. Such dampers may open and close based on the ambient air
pressure with respect to outdoors, or in response to an electrical signal from a controller or
another piece of HVAC equipment. Other make-up air dampers may be permanently kept open,
so there is always an open pathway between indoors and outside. In the case of the Broan
Automatic Make-Up Air Damper, this device opens in response to an electrical signal from a
compatible Broan exhaust device or from a universal pressure switch kit.
Nominal rated flow: the exhaust appliance’s rated flow at a static pressure of 0.1 in w.g. (25 Pa)
Outdoor air: air that enters a building through a ventilation system, through intentional openings
for natural ventilation, or by infiltration.
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Passive opening: an intentionally installed opening in the building shell for the purpose of
allowing a pathway for fresh outdoor air to enter the building. Passive openings do not utilize
fans to introduce the fresh outdoor air, but merely provide an opening for air transfer.
Pressure boundary: the primary air enclosure boundary separating indoor and outdoor air.
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Transfer air: air moved from one indoor space to another.
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2.
What is Make-Up Air?
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Sourced or adapted from ASHRAE 62.1-2010, Ventilation for Acceptable Indoor Air Quality.
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Sourced or adapted from ASHRAE 62.2-2010, Ventilation and Acceptable Indoor Air Quality in Low-Rise
Residential Buildings.