PSA: Time to remove the overrides

Hey friends,

Let's start this week's newsletter with a public service announcement:

If you've overridden your building's ventilation control sequences to mitigate the risk of COVID-19, it's (probably) time to release those overrides.

You're (most likely) wasting energy, increasing operational costs, and having a negligible impact on occupant safety.

In April, at our monthly members-only Zoom gathering, indoor air quality (IAQ) expert Aaron Lapsley gave an excellent presentation on a data-driven approach to IAQ.

The highlight for me was some of the results coming out of studies by a company called SafeTraces. They've developed the technology to safely mimic how a pathogen travels through a building so it can be tested.

So what does the data say? As Aaron said on LinkedIn:

"Increased filtration and outside air levels are great for indoor air... BUT they are unlikely to make your building less risky for pathogen transmission, i.e. they are very unlikely to move the needle on people getting other people sick indoors.

Pathogen transmission risk is vastly more concentrated at the room level than via recirculation of air from central (or even fairly localized) air handlers."

That's because 99.99% of simulated pathogens don't make it back to the AHU from the human that sneezed or talked them into a room.

The CDC's and ASHRAE's guidance recommending building operators to throw their outside air dampers wide open was based on an understandably conservative assessment of the available science at the time.

But that time has passed, my friends.

It's time for all of you building operators out there to remove the overrides on the OA dampers and demand-controlled ventilation sequences.

What do you think?