COVID and HVAC Filters
For Commercial and Industrial Systems
Twin City Filter Service is a premier supplier of high quality filters to the commercial and industrial HVAC filter community. We pride ourselves in the depth of our knowledge. And yes, the right filter, correctly maintained, can assist in the battle against COVID-19 in commercial and industrial buildings. To help our customers, friends and peers, we have gathered useful COVID filtration information as it pertains to the commercial and industrial HVAC filter community.
February 2022 Update. (Reviewed June 2023). Resources: ASHREA, NAFA, REHVA, BOMA, IFMA, AFE, USGBC, International Filter News, The Wall Street Journal, Bloomberg.
Synopsis of facts most repeated in the literature:
- Building air exchange rates should be no less than 3, with 3-6 preferred (a hospital rate is normally 12).
- Medical buildings and most airplanes are designed for HEPA. Your building is likely not.
- If your system is designed for it, use MERV 13 or higher.
- If your system is not designed for MERV 13, use the highest MERV your HVAC system is designed for, and consider plans for building upgrades. Do not use filters with higher ratings than your HVAC system specs.
Read on and stay safe.
Why Air Filtration is so Important in the Fight Against Covid
This Bloomberg article points out how concerned we were about surfaces and how concerned we should be about aerosols and HVAC filtration.
University of Oregon Air Flow Animation
From the University of Oregon Institute for Health in Indoor Environments, an animation showing indoor aerosol fate and transport. The last simulation suggests greater air intake, perhaps via an Economizer.
NAFA Air Filtration Best Practice Guidelines
NAFA’s robust Best Practices page has multiple COVID links and downloads.
Guidance for Building Operations During the COVID-19 Pandemic
Ashrae’s Guidance for Building Operations (PDF download) is a short concise article with many useful citations and links. Also see https://www.ashrae.org/technical-resources/resources.