NOT ALL RESIDENTIAL AIR CLEANERS ARE SAFE
Be sure to research what you sell to protect yourself from future product liability issues.
BY AARON ENGEL
T
he HVACR market has been inundated with dozens of air cleaning technologies and equipment over the last decade. Contractors have discovered this growing niche to be a lucrative market for promoting indoor air quality to consumers. The emergence of many research reports on the dangers of ozone, a gas that is a byproduct of some cleaning methods, however, should prompt contractors to research what methodologies are the safest or they could be opening themselves up to future product liabilities issues. Arm yourself with knowledge on how air cleaners work and determine whether they produce harmful byproducts, such as ozone, to not only provide your customers the safest possible IAQ, but to protect your business from possible liability issues.
OZONE DANGERS Ultraviolet germicidal irradiation (UVGI) technology isn’t new and has been used to disinfect air for decades and water for more than a century. There’s no doubt UV lamp systems effectively disinfect biological contaminants especially those that pass two UVGI effectiveness test standards: ANSI/ASHRAE Standard 185.1 for UVGI lamps in induct airstream irradiation; and ANCI/ ASHRAE Standard 185.2 for UVGI lamps for in-duct surface irradiation. Besides ductwork and plenum air supply disinfection, UV lamps also prevent mold
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Arm yourself with knowledge on how air cleaners work and determine whether they produce harmful byproducts, such as ozone, to not only provide your customers the safest possible IAQ. and other biological growth on evaporator coils and air handler interiors. Unfortunately, some UV technology for HVACR systems generate ozone, which multiple studies within the last several years have proven harmful to human respiratory systems. While ozone is sometimes an unintended byproduct, some UV lamp systems may also intentionally produce ozone by design. For example, some manufacturers purposefully use specific UV wavelengths that create ozone to produce the distinct, clean-smelling ozone odor. Whether or not a UV lamp generates ozone is dependent upon its wavelength. UV is produced in various forms: UV-A used for blacklights (320 to 400 nanometers (nm)); UV-B used in tanning beds (280 to 320-nm); and the most lethal germicidal wavelength, UV-C (254-nm) is ideal for disinfection. UV-C deactivates microorganism reproduction by altering their DNA structure. While UV-C is the most lethal for microorganisms, UV lamps using the UV-V wavelength at 185nm produce ozone.
UVC lamps at or above 254-nm do not generate ozone, whereas UV lamps at the 185-nm generate ozone through photolysis of oxygen and further reaction, according to the Environmental Protection Agency’s (EPA) “Residential Air Cleaners.” This new 75-page, comprehensive document outlines the strategies, advantages and disadvantages of all residential air cleaner methodologies. It states that ozone-generating models are detrimental to homeowners’ respiratory tracts, lungs and general health. Prior to the EPA document’s release, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) had already taken a similar position on ozone-generating air cleaners and their detriment to occupant health. ASHRAE’s 2015 publication “Position Document on Filtration and Air Cleaning states in Section 2.6: “Ozone is harmful for health and exposure to ozone creates risk for a variety of symptoms and diseases associated with the respiratory tract; Ozone emission is thus undesirable.” Section 3.2
of the document further states: “devices that use the reactivity of ozone for the purpose of cleaning the air should not be used in occupied spaces because of negative health effects that arise from exposure to ozone and its reaction products.” Still, other organizations have also carved out regulatory ozone requirements for consumers. For example, the U.S. Food and Drug Administration (FDA) was the first to set an ozone emissions limit of 0.05 ppm (50 ppb) for all medical devices. In 2008, the California Air Resources Board (CARB) targeted ozone emissions with a state-wide regulation requiring certification of all electronic air cleaners under UL 867’s test standard of 0.05 ppm (50 ppb) limit. CARB is expected to soon publish an update on ozone dangers of some air cleaners.
OTHER TECHNOLOGIES HAVE OZONE POTENTIAL Besides some types of UV lamps, the EPA has also stated electrostatic precipitators (ESP) and ionizers, which are air cleaning devices positioned in the airstream of HVACR systems, are also potential ozone contributors. Both methodologies use a powered electrostatic process to charge particles, that in turn, become attracted to oppositely-charged plates or other indoor surfaces to remove airborne particulates.
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FEBRUARY 2020
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