The City of Melbourne conducted a research project, The City of Melbourne Breath pilot, to examine how simple changes to ventilation systems in office buildings can significantly decrease the transmission of Covid-19, as well as reduce energy consumption. The need for the study arose from the impending return of up to 400,000 central business district (CBD) office workers.
“Bringing people back to the city safely remains a key priority for the City of Melbourne, and that’s why we have undertaken this pilot study,” said acting lord mayor Nicholas Reece.
Over three months, the pilot tested and evaluated three different ventilation systems in a vacant CBD building: displacement ventilation air conditioning, which supplies air from the floor level; in-ceiling air filters; and natural airflow through open windows.
The study found that:
- all three ventilation systems reduced the potential transmission of airborne viruses when compared to standard ceiling-based air conditioning;
- displacement ventilation air conditioning was the most effective and energy efficient system tested. It reduced Covid-19 transmission by 83%, while also reducing energy consumption by 20%. It is the most expensive to install, but there are no additional ongoing maintenance costs;
- in-ceiling air filters reduced virus transmission by 49%, but resulted in a minor increase in energy consumption; and
- opening windows reduced virus transmission by 53%, but increased energy use by up to 20% due to seasonal temperature variations. The study noted that opening windows is not available in all office buildings, and is not a viable solution due to Melbourne’s climate.
“This industry-leading research has identified simple but effective changes that can be implemented in office buildings to help workers feel safe, comfortable and protected. The research findings are publicly available online and free for any organization to access. We encourage building owners, tenants, and partners to take them on board, and to help us create more healthy and sustainable workspaces in the CBD,” said Reece.