Microbial Activity in HAVAC Systems

Microbial Activity in HAVAC Systems - A Serious IAQ Threat.
Contaminated indoor air is a growing issue worldwide. Experts know that certain airborne contaminants cause widespread discomfort and health problems, leading to absenteeism and a decrease in productivity. Healthy indoor environments could save billions in health care costs, lost work time, output and possible litigation.
The most offending contaminants are bioaerosols, regarded as the leading cause of allergies, SBS (Sick Building Syndrome) and BRI (Building Related Illness).
Bioaerosols are airborne contaminants that include microbes and the metabolic gases, cell fragments and spores, other toxins and waste products.
Airborne and surface microorganisms include pathogens (viruses, bacteria and mold which cause measles, chicken pox, Legionnaires' disease, aspergillosis, tuberculosis and other infectious diseases); allergens (bacteria and mold which cause allergic rhinitis, asthma, humidifier fever and hypersensitivity pneumonitis); and toxins (mycotoxins and endotoxins which cause toxic and allergic reactions, irritations and odors).
Among allergens, mold and mold products are the most common worldwide ? and mold can proliferate in A/C systems year-round. Exposure to mold initiates the release of histamines. Scratchy eyes and throat, congestion, breathing difficulties, allergy asthma and other complications can follow.
Almost every space is air-conditioned today, and a damp A/C coil is especially conducive to the growth of molds and bacteria. The unit's fan disseminates and recirculates microbes along with space and occupant-generated germs ? both room to room and person to person.
We can't count on help from air filters for two reasons: (1) Microbial growth occurs downstream of filters, so microbes will still flood the rest of the system and space; (2) Viruses and many bacteria are too small to be stopped by the majority of filters in use today.
IAQ experts agree that chemical bio-remediation is impractical, as it's harmful to humans, equipment and the environment; and it is only temporary. There is growing interest in UVC as the most practical, effective and continuous solution.
This UV is the "C" band, not the more familiar A and B. It's been used for more than 70 years to kill harmful microorganisms in many applications. But it wouldn't work in HVAC systems because conventional UVC lights suffered drastic output losses and thus "killing power" when exposed to cold and/or moving air.
The new generation of Steril-Aire UVC Emitters? is engineered to provide peak output specifically at HVAC conditions. Output is significantly greater than that of conventional UVC fixtures in HVAC applications. Independently verified output, award-winning fixture designs and patented application procedures all work in concert to kill infectious microbes while continuously eliminating mold and bacteria on coils and in drain pans.
Though originally developed to improve IAQ, Steril-Aire's multi-patented methodology also rewards users with significant energy and maintenance benefits. The UVC Emitter eliminates the bio-film and dirt that foul surface heat transfer ? continuously cleaning and maintaining coils and drain pans to "like new" conditions. The process brings crucial improvements in coil heat transfer, efficiency and pressure drop. Many building operators report energy savings of 15-30% and much higher.
Those who use Variable Frequency Drives (VFDs) quickly see more of a VFD's promised energy savings once the Emitters have cleaned the coils. As a result, those considering VFDs may have more incentive to use them in concert with UVC Emitters. Constant speed fan users will need to check system conditions as many will be able to revert to original design settings for substantial energy savings.
By keeping coils and drain pans clean and odor-free, UVC Emitters reduce or eliminate costly coil, drain pan and plenum-cleaning programs; and maintenance crews are no longer exposed to biocidal and cleaning agents or other chemicals required for these tasks. Also, coils and drain pans no longer seed the system with mold, bacteria and their products so ducts and occupied spaces stay cleaner and odor-free too. By combining energy and maintenance savings, a typical UVC installation will pay for itself in 3-5 months.