ASHRAE Epidemic Task Force – Update on Ventilation Recommendations
Initial, knee jerk, recommendations from ASHRAE were to increase ventilation air and forego demand based strategies. As a response to COVID19, ASHRAE established Epidemic Task Force to help deploy ASHRAE’s technical resources to address the challenges of the current pandemic and future epidemics as it relates to the effects of heating, ventilation, and air-conditioning systems on disease transmission in healthcare facilities, the workplace, home, public and recreational environments.
On October 22nd, 2020, enVerid hosted a webinar presented by William Bahnfleth, Ph.D., P.E., chair, ASHRAE Epidemic Task Force, The webinar provided an update on the Epidemic task force recommendations for building mechanical systems readiness.
The ASHRAE Epidemic Task Force first sat on March 29th to develop recommendations for building mechanical systems. Since that time, there has been significant research into strategies that mitigate viruses and also consider the economic impact of those strategies. A key study showed that increasing filtration was as effective as increased ventilation at reducing the risk of infection. It also correlated the cost of implementing the two strategies. The following graph from this study has two key takeaways:
- MERV13 filters are as effective as increased ventilation
- Proper filtration is much less expensive than ventilation
The ASHRAE Epidemic Task Force has updated recommendations as follows:
- Provide minimum ventilation per ASHRAE 62
- During pandemic, demand based ventilation strategies should be disabled
- Increase filtration to MERV13
- Air cleaners with standalone HEPA/UVC have demonstrated to be effective.
- From other studies (Harvard) it is shown that 6ACH in a space is optimal. (Note: ACH is not a reference to ventilation air, rather the total supply air to the space. With greater ACH, the filtration systems become more effective.)
- Maintain space T & RH
Check out the complete webinar here: https://enverid.com/resources/webinar-series-covid-iaq-new-best-practices/
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