HVAC Litigation

I had to delete post.

Could he be referring to mold contamination from water intrusion? I’ve had several combination commercial units over the years that were replaced as a result of mold and or bacterial contamination brought on by the presence of excessive moisture. The owners tried cleaning the units, then installed UV cleansing systems, but still could not stop the mold and or bacterial infection from recurring.

The simple presence of some moisture surely would not in and of itself be reason to replace an HVAC system. We all encounter condensation leaks, plumbing leaks onto a unit or roof leaks from the exhaust vent penetration with water flow all the way to the fire box. I’ve never heard of a unit being replaced for any of those reasons as long as the housing was not rusted through or showed some other signs of disrepair.

Understand that UV will denature bacterial DNA with extended exposure. I am not aware of any studies which indicate that UV exposure to mycelium fragments or spores in the fraction of a second exposure typical when these particles are in the air flow have much of any effect.

I very much would love to have the opportunity to do some viability studies comparing the entrance/exit viable plate counts for both bacteria or fungi. I my lab, I have a laminar flow hood where fungal culturing is done. 2 high intensity UV lamps are used for 20 minutes prior to biological work. This is done in a static environment to eliminate bacteria from the stainless steel work surface.

If anyone can provide copies independent research to show that momentary exposure to UV is effective in deactivating fungi or bacteria, please forward and I will post on our indoor air quality forum under the HVAC discussion forum


Jeff Deuitch
Administrator, The Indoor Air quality Forum

Well first if you are doing EW work I would not be posting this question on a public discussion board. It can be used against you to discredit you by the opposing council. I have seen it happen.

What you need to do is to contact the manufacturer of the equipment. Get it in writing from their technical department, they will provide it for you. This will be Gospel in the eyes of the court.

Good luck on the case.

Hey Jeff;

Check out these links:








Sounds as though the EPA found some of these UVC devices to actually be quite effective.

What’s your take on these systems?

Thanks for the links.

I have read the EPA document and there seems to be good promise for non spore forming bacteria and for one virus examined. Interestingly there were no results listed for any controls. That is, input/output culture reductions with no UV present.

Can anyone tell me if the intensity (dosages) employed were typical of those used in ordinary HVAC systems or were these specialized devices? Notice how the efficiency in most trials went way down when spore forming bacteria were used? Fungal spores are orders of magnitude more difficult to kill than bacterial spores. Most bacteria do not produce spores. Notable exceptions are species in the genera *Bacillus *and *Clostridium. * Bacillus anthracis has received widespread attention since it the causative organism of the disease known as anthrax.

Thanks again for the post.

Jeff Deuitch
Administrator, The Indoor Air Quality Forum
Palmetto, FL