On January 11, 2022, Humber College sent this message out to all employees regarding campus ventilation.

In response, we would like to share this message with all members, written by Des McCarville, Professor of HRAC, certified member of the JOHSC, and local steward in FAST:

As someone who has been involved in discussing the role of ventilation in the transmission of the COVID – 19 virus, I felt obliged to respond to today’s email from the VP HR. It is unfortunate that the email was sent on the day that Ontario reached a high in hospitalizations due to COVID as well as new ICU admissions.

Perhaps a little history is in order first. The HVAC systems at Humber reflect the age of the existing buildings. Some are recently constructed and fairly effective while others have been around for many years and are consequently inadequate.

With this in mind, Local 562 early expressed concerns about the efficacy of ventilation systems at the College. In July 2020, a few months into the pandemic the World Health Organization released an opinion that ventilation systems could be a possible vector for the disease. Local 562 raised this issue at the Union/College “Return to Campus” (RTC) meeting on July 15, 2020. The College’s reply was that Public Health Agency Canada (PHAC) considered the method of transmission to be “droplet based” and that the ventilation system was not a vector. Nothing needed to be done. The Local raised the issue again on August 26, 2020, and again, was told there would be no changes to ventilation. On September 2, 2020, the College provided a summary of the current ventilation system at Humber, and once again, re-affirmed there would be no changes to the system, as the current system met health guidelines.

In September of 2020, the Centre for Disease Control (CDC), based in Atlanta also raised the possibility of airborne transmission through the HVAC ventilation system. The Local cited this reference at a meeting of the Humber North Joint Health and Safety Committee meeting, also in September 2020. The College’s response was the same as it was in July. Nothing would be done unless PHC determined this to be the case.

Finally, in October of 2020, PHAC acknowledged to the possibility of airborne transmission. At the November meeting of the Humber North JOHSC, the College accepted this finding but continued to rely on administrative controls to reduce the risk of viral transmission. Similarly, at the November 11, 2020 and November 25, 2020 RTC meetings, the College also acknowledged this finding but maintained no changes to ventilation were necessary. These controls consisted of requirements for social distancing, masking, hand hygiene and remote off-site learning. Labs that have been allowed to function have done so at a reduced occupancy.

To a large extent, this strategy has been successful and the College should be commended for this effort. Facilities should also be applauded for its effort to increase the use of MERV 13 filtration in HVAC systems. This level of filtration has been proven to remove virus particles from the air stream. However, there was always the question of the ventilation system as a whole. It was always apparent that unless the virus was eradicated completely, a thorough examination of ventilation would be necessary.

Surprisingly, this does not seem to have been done. When the College determined that Humber would return to “normal” in January 2022, it did not reference any of the ASHRAE Indoor Air Quality (IAQ) standards mentioned in the VP Human Resources email. Rather, it chose to populate classrooms using the Space Utilization Report (SUR) of 2019. This report outlines the number of occupants that can safely be placed in a classroom that contains desks and chairs. It says nothing about ventilation.

For example, I was assigned a room for a class of 46, which the SUR stated could contain 46.  Having some experience in that room from 20 years of teaching at the College, I asked Facilities to review the assignment. Using the 2013 ASHRAE IAQ standard, Facilities determined the maximum occupancy should be 29, including me. I showed the information to my AD, a professional engineer. He ignored the data and referred back to the SUR number of 46.

It soon became apparent that using the ASHRAE standard of 2013 would greatly reduce the ability of the College to “fully” populate the classrooms as normal. This would require more classes, more professors and obviously more money. The cynic in me might ask “Did the College search for a standard that would justify full classrooms such as the standard was announced in December 2021? – ASHRAE IAQ 2019.”

At first glance this would seem to be a proper solution. The 2019 standard is newer and more recent, so shouldn’t it be better when we are dealing with COVID-19?  There are two answers to this question, one obvious and the other that will require investigation.

First the obvious answer: The 2019 standard was created before the pandemic! Consequently, it has nothing to say about how ventilation systems can mitigate transmission of this virus. To use it as the basis for room occupancy when the transmission rate of the virus has increased by 4 to 8 times beggars belief.

The second answer will require discussion and investigation by the JOHSC. But to be as brief as possible, standards such as the ASHRAE IAQ 2019 do not exist in a vacuum. They co-exist with other standards required by Building Codes and sometimes these standards can stand in opposition to each other. Designers of HVAC systems know this and often have to search for an acceptable median.

Such is the case with IAQ standards and Energy Efficiency standards. IAQ standards will push for as much outside air as possible given the presumption that this air is healthier than recirculated indoor air. But in the middle of January, this ventilation air has to be heated and in the middle of July, it must be cooled. Such action will raise the energy (carbon) footprint of a building. In a period of profound concern for the effects of climate change, it is understandable that HVAC designers should want to reduce to as great an extent as possible the introduction of outside air. They will be continually tweaking standards to achieve this result, as they may have done with the 2019 standard. Did this tweaking result in a reduction of outside air?

This may in the long run give us a healthy working environment with as a low of an energy cost as possible. But is it the proper strategy to be following in the middle of a pandemic caused by the transmission of an air-borne virus? Clearly, this is a strategy that needs further investigation and discussion. But for now, we should be increasing our ventilation rates and matching our class sizes to what these systems can safely deliver. We should pause the return to on-site lectures and labs until we are sure it is safe to do so. At the moment, we do not have that information.

Des McCarville

Local 562 Health and Safety Rep – Humber North JOHSC