Classroom ventilation exceeds standards: report

August 31, 2021 5:00 PM

Ventilation in all classrooms at Western meets – and in most classrooms even exceeds – the high standards of measurement to prevent potential airborne spread of coronavirus, according to a recent analysis of the university’s buildings.

Results of an airflow assessment in all classrooms should provide an enhanced degree of confidence as students, faculty and staff return to campus this fall, said Elizabeth Krische, associate vice-president, facilities management.

“The analyses show our ventilation systems are in outstanding condition; and the air exchange in our classrooms is operating as it should,” she said.

A classroom-by-classroom analysis can be viewed online.

Healthy building environments play an important role in combating infectious diseases, according to the Harvard T.H. Chan School of Public Health, which through its Healthy Buildings for Health program has outlined air-exchange recommendations as follows: three to four air exchanges per hour is a bare minimum recommendation; four to five air exchanges per hour is considered ‘good;’ five to six exchanges is rated ‘excellent;’ and more than six is rated ‘ideal.’

At Western, all but a handful of rooms meet the ‘ideal’ or ‘excellent’ standard – some of them with more than 20 air exchanges per hour.

An analysis of all classrooms at Western show they meet or exceed airflow standards. Infographic by Rob Potter, Western Communications
An analysis of all classrooms at Western show they meet or exceed airflow standards. Infographic by Rob Potter, Western Communications

“We have a sophisticated building automation system for our heating and ventilation, likely one of the best in the country, and have invested heavily in air-handling and ventilation systems,” Krische said.

“To help ensure both the health and peace of mind of the Western community, we hired a consultant to independently assess the air exchange in a representative 15 per cent of classrooms. Then five members of Western’s environmental systems team spent two weeks, full-time, measuring and analyzing 388 spaces including all classrooms and some general spaces to see if we could identify any gaps that needed to be addressed in combating the spread of the coronavirus,” she explained.

The findings 

The analysis found 99 per cent of rooms have ideal or excellent ratings when buildings draw maximum airflow from outside. Even when the outside air intake is reduced to ‘minimum’ levels (to cool a building more efficiently and provide greater comfort in humid weather, for example), 94 per cent of classrooms are at ideal or excellent ratings.

The few rooms that rated below four air exchanges per hour are now equipped with air purifiers to improve their air quality even further.

Beyond measure 

These measurements and measures are in addition to numerous other steps Western has taken to upgrade and monitor air quality since the pandemic began.

They include following industry recommendations of the epidemic task force of the American Society of Heating, Refrigeration and Air-conditioning Engineers (ASHRAE) such as: wearing masks; optimizing building ventilation, filtration and air cleaning; optimizing air distribution; and ensuring HVAC (heating, ventilation and air conditioning) systems are working as they should.

Western has also upgraded its MERV (minimum efficiency reporting value) air filters to MERV 13, where possible, and added air purifiers in specialty areas, such as music practice rooms and Health Services patient examination rooms.

Building ventilation fans are ramped up two hours earlier and extended two hours later in the day to keep the air as fresh as possible during normal business hours. Building fans now run continuously during hot/humid days, where in pre-pandemic years they would shut down intermittently to reduce energy consumption.

Some buildings have also undergone deep energy retrofits to improve function and efficiency.

Although Western’s environmental systems team focused primarily on classrooms and not the buildings’ common areas, Krische said, “you can extrapolate from these results that if there’s ideal flow in the classrooms, the rest of the building is functioning similarly well.”

Additional steps Western is taking to ensure a safe campus include a mandatory vaccine policy, an on-campus vaccination and testing centre, enhanced cleaning and sanitization measures, daily health screening and a requirement that everyone wear three-layer masks while indoors.