Reasons Why New Evaluation Methods Are Needed For Air Cleaning Devices

There are many new untested air cleaning devices

Air cleaning devices have a wide range of functions, applications, and uses. These days they’ve drawn notable attention because of their ability to lend a helping hand in the fight against preventing the spread of COVID-19. In fact, since the pandemic started the HVAC industry has seen many new air cleaning device manufacturers and some producing an array of products for various applications. Some of the existing products such as; electrostatic filter media, plasma generators, high MERV rated media, and UVC germicidal irradiation have been around long enough that they have been independently tested and in some cases even earned UL product listings. Some of the newer products include; Ionizers, Photocatalytic Oxidation Generators, and Hydroxyl Radical Generators. Many of these new products have varying mechanisms of action that perform the actual “cleaning” of the air. Needless to say anyone trying to make heads or tails out of manufacture provided product literature can easily be overwhelmed.

With a simple measurement standard how could the water be so muddy?

An air cleaning device efficacy is typically measured by the change in downstream contaminates measured. A simple measurement of contaminates upstream of the air cleaning device divided by the resulting contaminate rate downstream (#/m^3). The resulting ratio is typically considered its efficiency. Air cleaners with a high efficiency are considered better than those with a low efficiency. However, this often-misunderstood simplification of the matter results in manufactures construing data for marketing purposes. Given all the new products any test that is to be a standard will need to accommodate to the variant in the mechanism of action. This very topic was the subject of an ASHRAE (American Society of Refrigeration, Air Conditioning, and Heating Engineers) technical feature article written by Brent Stephens, PH.D., Elliott T.Gall, PH.D., Mohammad Heidrinejad, PH.D., Delphine K. Farmer, PH.D.. The title of the technical feature was “Interpreting Air Cleaner Performance Data”. The focus of the feature was to highlight how easily manufacturers can skew product testing data that is presented to the public. Clearly defined parameters and consistent / continued testing is what a product needs to be fairly evaluated for its ability to clean air.

Two Takeaways...

Two things important to consider according to ShackHVAC, & ASHRAE is the air cleaning devices efficiency and the products UL listing. A product’s UL listing means the product has undergone specific testing to verify it meets required industry standards. If a product has attained a listing it means it meets those specific standards and is periodically retested for compliance certification. Having a UL listing as an air cleaner certifies that the efficiency data presented has been fairly evaluated based on its mechanism of action. Openly presenting the air cleaners testing parameters reinforces its reliability and viability as a product that potentially could be more beneficial than harmful.