TCHC’s quest to improve Indoor Air Quality for tenant comfort
Historically, high rise residential buildings, including Toronto Community Housing (TCHC) buildings, have been built with a pressurized corridor ventilation system where rooftop make-up air units supply fresh air to the building corridors. The washroom exhaust fans help to pull the fresh air from the corridor into the unit through openings below the unit entry door to make-up the air that had been pulled out of the tenant units by the exhaust fans.
There are a few challenges with this ventilation approach, especially when buildings are quite tall, or when the openings beneath the unit entry door are fully sealed off and prevent fresh air from entering tenant units. In some cases, this results in ventilation that is not balanced from floor to floor and can even cause the transfer of odours between tenant units.
Since 2018, TCHC has been working with the University of Toronto and The Atmospheric Fund (TAF) to study ventilation systems and improve air quality in our buildings. Improved air quality is important for occupant health and comfort.
The work completed to date has been focused on the use of computer modeling tools that help us to identify the most effective retrofit strategies for TCHC. The next phase of work in the partnership is to do physical testing in buildings to validate the computer model results.
Building Prototypes for Testing
“We are studying two buildings that are nearly identical, except one has two additional floors; one building is currently undergoing a major system upgrade while the other does not yet have work underway,” says Brendan Slyne, a Design Manager in the Mechanical & Electrical Engineering Unit of TCHC's Facilities Management Division. His team oversees design for all heating, ventilation, air conditioning, plumbing and electrical systems across our buildings.
“This situation provides us with the chance to measure and compare performance of a centralized pressurized corridor make-up air system against a decentralized Heat Recovery Ventilation system.”
In the testing complex, TCHC is transitioning from a pressurized corridor ventilation strategy to a compartmentalized ventilation strategy. This means that each unit has its own ventilation system. Although TCHC’s current centralized system is common to this type of building and provides adequate ventilation, the compartmentalized approach is more efficient and would provide improved indoor air quality. It guarantees that air flow to each unit is balanced and unaffected by its location in the building. With the new compartmentalized system, each unit will be directly supplied with fresh air. If there is an issue with air quality in one unit, it will only affect that unit and will not move throughout the building into other units.
The ventilation retrofit to one of the buildings is still in the early stages, but we are excited to evaluate the outcome. We know that these types of retrofits can be disruptive to tenants while they are going on. But this testing will make sure performance improvement will have a positive impact on lives of tenants over time.
NSERC Grant
To make sure this important research continues in our communities, TCHC has applied for the Natural Sciences and Engineering Research Council of Canada (NSERC) grant through a joint proposal with the University of Toronto. The NSERC is a federal agency responsible for funding natural sciences and engineering research in Canada. It directly funds university professors and students as well as Canadian companies to perform research and training.
TCHC’s unique portfolio of buildings presents opportunities for groundbreaking research to provide insight into innovations that impact our tenants in a positive way. The partnership with the University of Toronto and TAF will help validate the work TCHC is already doing to improve air quality in buildings and pave the way for the preferred ventilation system in our future retrofit projects.
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