You asked … Ventilation

You asked … Ventilation
Posted on 06/17/2021
You asked … Ventilation

We have received many questions from parents about the actions we have taken to improve ventilation at OCDSB schools in response to COVID-19.

Since August 2020, the OCDSB has received $22.8 million in federal and provincial funding towards improving ventilation and air quality in district sites. We have put this funding to use in a variety of ways.

Actions taken before September 2020

The District prioritized work on ventilation during the summer of 2020 to ensure that schools would be ready to re-open in September 2020. The work included:

  • Recommissioning of all heating, ventilation and air conditioning (HVAC) equipment, which included operational testing/inspection, repairs as needed, thorough cleaning and filter changes; and
  • Reprogramming of ventilation systems to comply with the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) standards and public health recommendations, including:
    • Creating purge cycles before, during and after school that exchanges the building air with 100% outdoor air at a rate of approximate six complete air changes per hour; and 
    • Increasing ventilation rates during other school hours to a fixed, constant rate of 3-4 air changes per hour.

Actions taken since September 2020

Short-term measures focus on enhanced air purification using high-efficiency particulate air (HEPA) filtration. The District ordered 1,250 units. Of these, 800 units were distributed in the fall of 2020 and the remaining 450 units were received and distributed in the spring of 2021. 

Distribution of the HEPA filtration units is based on the following criteria:

  • Classrooms where the increased ventilation measures noted above were not possible due to the nature of the HVAC equipment;
  • Isolation Rooms with a higher potential for airborne virus particles;
  • Classrooms where the more important steps of wearing masks, hand washing and distancing may not be achievable (e.g., all special program classrooms); and
  • All junior and senior kindergarten rooms across the District.

Long-term measures

Staff are working on implementing infrastructure upgrades at various sites in order to provide increased ventilation capability and/or add permanent filtration options. 

This work includes:

  • Air purification improvements, including upgrading to MERV-13 filters, new ultraviolet (UV) filtration and bi-polar ionization filtration systems.
  • Window replacement
  • Major equipment renewal (such as HVAC replacements, unit ventilator upgrades, rooftop unit upgrades and HVAC control upgrades). These measures will allow us to implement the enhanced ventilation program noted above.

Physical work is currently underway for some of these projects. The larger types of capital projects (window replacement and HVAC upgrades) are at various stages of the design, tender and award phase. Most of this work will begin in July 2021 and will extend until the end of December 2021.

But what about carbon dioxide monitoring?

On the topic of ventilation, we have also received questions about carbon dioxide monitoring.

Most of our schools have carbon dioxide (CO2) monitoring performed on an ongoing basis through our Building Automation Systems. Before COVID, CO2 levels were used to balance ventilation rates throughout the day (ie: increase ventilation when CO2 levels are high and decrease ventilation rates when CO2 levels are low). 

When COVID started, we adopted the ASHRAE recommendation to remove CO2/demand-based ventilation controls. What this means is that while CO2 levels are still being monitored, CO2 levels have been disconnected from ventilation rates, which are set at higher levels to encourage the flow of fresh air through schools.

Learn more about carbon dioxide monitoring in schools here.

I have more questions about my school’s ventilation. Where should I go for help?

Please contact your principal to learn more about actions taken at your school.

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