We are reviewing the current state of ventilation in our buildings, and how this affects the spread of COVID-19. We were pleased to discover a June 2, 2021 Centers for Disease Control (CDC) policy on this important matter. The U.S. government agency recommends ‘a layered approach to diluting potential contaminants’ in buildings. But what does this mean?
What’s At the Heart of CDC’s Layered Approach?
Centers for Disease Control believes in applying ‘multiple mitigation strategies’ to reduce COVID-19 spread in buildings. It agrees ventilation improvements are essential for diluting potential contaminants in buildings. Although it wants to team these with layered ‘physical distancing, face mask wearing, hand hygiene, and vaccination’.
The CDC continues by emphasizing SARS-CoV-2 virus particles spread more readily between people indoors. Particularly when compared to outdoor conditions where a light wind can scatter concentrations. That’s because lower concentrations are statistically less likely to cause infections, especially if building occupants also take precautions.
Building Interventions Diluting Potential Contaminants in Buildings
Most new buildings may not require ventilation modifications the agency says. However, upgrades could ‘increase the delivery of clean air and dilute potential contaminants’. It recommends servicing ventilation systems when preparing a building for reoccupation after lock down.
There’s no certainty whether viruses can cause contamination on return air grilles, in return air ducts, and on heating, ventilation, and air conditioning filters. Although we imagine wearing face masks and sanitizing hands would further reduce that risk. Building owners should at the very least consider the following strategies according to CDC:
1… Open windows, inspect / maintain exhaust systems, disable demand controlled ventilation, reposition outdoor air dampers.
2… Use fans to increase effectiveness of open windows. Reposition supply / exhaust diffusers to create directional airflow.
3… Add portable HEPA-type pleated, mechanical fan / filter systems, consider adding upper room ultraviolet germicidal irradiation
We’ve included a link to the CDC policy statement in case you would like to explore the technicalities further. Seek advice from a ventilation specialist before reaching any decision.
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Preview Image: HEPA-Type Air Filter Diagram
