Humber College has not utilized portable recirculating HEPA filtration units, but we’ve allowed our college community to bring their own if they choose. We’ve been able to address any concerns pertaining to the relationship of Covid-19 transmission and HVAC operations by talking to one of the points below.
1. Ensure that the HVAC equipment provides sufficient Supply Air and Outside Air to the spaces. Use ASHRAE 62.1 as a reference.
2. Maintain space temperatures (21-23 deg.C) and humidity (30-50% RH) levels as much as possible.
3. Change the minimum filtration level at RTUs and AHUs at MERV 13 minimum
4. Continue all Preventative Maintenance work and show proof when asked upon.
5. Continue all cleaning and disinfection procedures at a higher frequency.
Local recirculating HEPA filtration can definitely be a supplemental solution to a centralized HVAC system, but it has limitations. For one, replacing a dirty HEPA filter locally may require additional procedures and we argued that as long as we satisfy all the points above, there will be no need for a recirculating HEPA filter at the room level. I hope this helps.