Prior to the onset of the COVID-19 pandemic in early 2020, most people would never think about how many times the air inside their office building was cycled, filtered, and ultimately exchanged for fresh outside air. However, as employees are beginning to return to the office this summer, many are thinking about how clean the air inside their office really is. Building readiness continues to be a major concern.
The definition of an air exchange is pretty straight forward. Essentially it is the number of times the total volume of air in a room or building is completely replaced over the course of an hour. In most cases a single-family home is designed to have between .35 and 1 air exchange per hour1 depending on the square footage and number of occupants. Unfortunately, the answer to how frequently air should be exchanged in an office building or commercial space is not quite as straight forward as a single-family home.
Variables such as the number of people in the office, the office layout, they type of facility, and even the function of the room all come into play when determining the number of times, the air should be exchanged within a building. We recommend consulting ASHRAE Standards 62.1 & 62.22 to ensure that your building is properly ventilated based on its needs. Alternatively, you can reach out to our team of Engineers and let us hep you figure it out!
In most cases, offices did not shut down completely during the pandemic. Building managers still ran the HVAC system to cycle air in within the building to prevent the buildup of mold, dust, and other contaminants within the building. In fact, most building managers have actually increased the number of air exchanges that take place every day to increase ventilation and reduce the risk or COVID-19 transmission within the building, which can have a detrimental effect on the energy efficiency of the space. If your building is one of the few that did shut down completely during the pandemic, we encourage you to have your building’s maintenance manager reach out to us so that we can assist you in safely restarting the buildings critical systems including the HVAC and water systems (You can read more about that here »).
Quick References
1. https://www.cdc.gov/coronavirus/2019-ncov/community/office-buildings.html
2. https://www.ashrae.org/File%20Library/Technical%20Resources/Bookstore/previews_2016639_pre.pdf
3. https://smartairfilters.com/en/blog/ashrae-per-hour-office-residential-school-virus/
4. https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2
5. https://smartairfilters.com/en/blog/what-is-air-changes-per-hour-ach-how-to-calculate/
1https://smartairfilters.com/en/blog/ashrae-per-hour-office-residential-school-virus/
2https://www.ashrae.org/technical-resources/bookstore/standards-62-1-62-2