Technical Corner: A Quantum Leap Forward in HVAC Hygiene (Part 2)

Recent technical articles by ASHRAE and indoor air quality associations point out the far-­‐reaching effects of poor air conditioning hygiene on building owners and occupants.

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Personally I have seen air handlers in a large hotel with a black layer of mold lying on the floors, walls and ceiling often a 1/16 of an inch thick or more. When one sees this sort of thing i actively working commercial buildings, you cannot help but wonder just what is in the air occupants breath? Since most biological spores are below the limits of human visibility an occupant just can’t see them but many times can discern their smell.

I have witnessed the skeletons of dead animals inside the filter rack compartment in hospital air handlers providing air to patients.

_Of course most maintenance staffs throughout the country have witnessed at one time or another condensate drain pans filled with fungus, bacteria, and a “biological soup” as shown in the accompanying photograph we took at a major hospital.

Since all of the air breathed by occupants passes across this debris, what sort of air are you actually breathing in? Do occupants breathe in bacteria or mold spores generated by the air handler, and can this affect one’s health?

The short answer is yes.

Air conditioning interiors are dark and damp, ideal environments for growing fungus (mold) and bacteria. Mold and bacteria produce odors, most always a “musty” smell, but can take on other forms of odor as well.

And microbes are not just limited to common bacteria or mold either.

Take a hospital for example. Ar conditioners are set up to re-circulate air (it is too expensive to furnish fresh outside air all the time to occupants). When air is recirculated in hospitals, patients coughing release germs into air, which is recirculated back to the air handler.

A certain amount of these germs alight onto interior surfaces, where they can grow and amplify.

How do we know this occurs? We once had a swab taken from an interior surface of a hospital air handler and found bacteria not generally considered present or expected in the environment.

To be continued……………………..

Please feel free to leave your comments below.

Lynn Burkhart is the founder and president of Controlled Release Technologies, Inc. located in Shelby, North Carolina. More information about the company, and its products, can be found at and by calling (800) 766-9057.

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