Make-Up Air Units

Uploaded by onphajm on 13.04.2010

The following video is part of a series of videos being produced by ONPHA to provide
general information about various building components and the preventive maintenance
that should be undertaken to maintain them.
Carrying out regular, ongoing preventive maintenance on all components and systems in your property
is important, whether it is a large multi-residential development or a small site with only a few
units. It's a known fact that having a preventive maintenance plan in place is, over the long
run, more cost effective than making repairs as components fail.
The various types of make-up air and ventilation systems in a multi-residential building are:
kitchen and bathroom fans, roof top units, garage fans, and other exhaust fans that vent
air directly outdoors or are part of a larger duct system.
A building's make-up air and ventilation systems are designed to provide the occupants with
a healthy environment and plenty of fresh air. Building exhaust systems take out large
volumes of air from the building space. If this air is not replaced at the same rate
it is expelled, the building will experience a negative pressure (the air pressure outside
the building is greater than the air pressure inside the building).
Some of the most common indicators of a negative pressure problem include the suction pressure
that makes exterior doors difficult to open, exhaust fans that don't work properly, drafts
around doors and windows, poor indoor air quality, and infiltration of outdoor air.
These problems are more pronounced during the cold season when windows are kept closed,
reducing the natural pressure-balancing effect.
This is a common style of a rooftop-mounted make-up air unit. Fresh outside air is drawn
in and passes through a series of filters to remove dust and other air- borne pollutants.
The amount of fresh air brought in is regulated by electrically operated dampers depending
on how much fresh air is required at any given moment. In some units the incoming air is
heated slightly by a gas burner. This heated air is then blown into the building, through
a series of ducts and fans.
Following a regular preventive maintenance plan will keep vents and equipment properly
serviced and maximize energy efficiency. This will also prevent unwanted moisture, bad odours
and potentially dangerous gases in garages and mechanical areas from accumulating in
the building.
Other benefits of a properly maintained ventilation system include:
supplying conditioned replacement air that can be heated, cooled, humidified or dehumidified
as required assisting in the reduction of mould
greatly reducing the infiltration of cold outdoor air and drafts through open doors
allowing the proper operation of exhaust systems improving indoor air quality
keeping cooking smells and cigarette smoke in units
eliminating suction pressure at exterior doors decreasing the load on existing HVAC systems
lowering energy costs by as much as 35%, and maintaining a more comfortable and productive
environment for your building.
As well, preventive maintenance of equipment, vents, exhaust, pump and motor systems will
extend the service life of your equipment and reduce utility costs by avoiding excessive
wear-and-tear and wasted energy.
In fact, it is a requirement under the Ontario Building Code to ensure a sufficient supply
of fresh air in residential areas, such as units and common areas, as well as service
areas like electrical and elevator rooms.
An effective make-up air unit maintenance program includes the inspection of:
Roof-top make-up air systems Filters
Ducts Air flow, and
Your annual preventive maintenance plan should include regular inspection, cleaning, and
servicing of your ventilation system by a professional service. Work done by a professional
tradesperson ensures it is performed properly, efficiently, and according to the manufacturer's
specifications. This is especially true for natural gas make-up air units, and larger
properties that require additional technical equipment and more qualified labour.
Sample Maintenance Tasks include: Check Chimney and exhaust systems
Check and lubricate moving parts Check belts and pulleys
Check motor shaft play Change filters
Check fresh air intake Ensure work area around equipment is clean
and safe Complete service logs and contractor reports
Replacing make-up air units is an expensive and labour intensive endeavour. New units
for a typical 50-unit apartment building can cost from $5,000 to $25,000 for the unit alone.
Installation costs can vary significantly and may involve renting a crane and obtaining
special permits for blocking lanes. Make-up air equipment can take 8 to 12 weeks to be
manufactured, as most roof top units need to be custom ordered.
Your site staff can perform some simple maintenance tasks, provided they have completed proper
safety and shut down training. Staff can replace filters and screens, and clean and dust mechanical
rooms, around furnaces, air grills, and air ducts. The only equipment required to perform
these tasks are a mini shop vac, filters, a dustpan and a broom.
The results will be improved air quality and a cleaner appearance. Make-up air vents in
your common areas will no longer have those unsightly dirty grill covers. Properly working
kitchen and bathroom vents will result in reduced moisture and odour problems. You will
also save money on your hydro and gas bills. Your equipment will run more efficiently and
last longer with clean filters and vents, properly adjusted belts, and lubricated parts.
Regular preventive maintenance of your building's ventilation system and its components will
ensure that any small problems are detected before they become big ones. This also means
seamless and reliable operation for the people who call your building home.