H.L. Turner Group affiliate Turner Building Science & Design’s (TBS) Steve Caulfield, PE, spoke with the Concord Monitor’s Granite Geek David Brooks, to explore approaches to protect against COVID.
With a growing need to improve indoor air quality for businesses across the nation due to the COVID-19 virus, Caulfield, a Certified Industrial Hygienist with over 30 years of experience, and the other mechanical engineers at TBS have been busy performing building evaluations and developing solutions to provide safer and cleaner indoor spaces.
“We’re seeing a lot of people trying to increase the amount of air replacement, the air change rate. The problem we run up against is the engineering problem that on a hot day your system is only designed to cool so much outside air. Beyond that you either raise the temperature or humidity in the space, or both,” Caulfield said. “You can’t just go to every building and open every outside air damper.”
As David Brooks explains, this same complication comes up with air filters. Air filters are calibrated on the MERV (Minimum Efficiency Reporting Value) scale, with bigger numbers removing smaller-sized particles. Most buildings have filters that are rated as MERV 8, but as Caulfield points out, “it’s not until you get to about a MERV 13 that you start removing 90% or more of virus-sized particles.”
Unfortunately, a MERV 13 filter generally won’t fit into the designated filter space, and the tighter filter puts an additional burden on motors. As Brooks points out, the added work could burn out motors and will certainly reduce airflow, allowing viruses to build up – the exact opposite of what you want.
For over 30 years, the professionals at TBS have been working to understand the complicated yet delicate nature of balancing HVAC design and system controls to optimize indoor air quality. To find out how to improve the air quality in your building, contact our experts.