Optimizing UV-C exposure for airborne disinfection
September 27, 2021
By Kaila Hutchison, Product Marketing, PTFE
In our previous blog, we began to address how UV light is a well-known disinfection approach to microorganisms that live in air, water, and on surfaces. Where common methods of disinfection come to mind – such as chemical germicides or anti-microbial metal materials (Silver, Iron, Copper) – UV has become more prevalent across industries looking to add another layer of defense. We explained how UV-C light is effective at disinfection and which key elements ensure proper UV dosage.
Yet, since the onset of the COVID-19 pandemic, we are turning our attention more towards disinfection methods for airborne infectious diseases, which many people perceive to be more complicated than the inactivation of microorganisms on surfaces.
Disinfection for airborne pathogenic microorganisms
Disinfection of airborne pathogens relies on emerging technology and device builds that optimize the UV-C exposure to a moving airstream. We see more and more evidence of this as it moves into mainstream applications across industries.
With UV-C lamps falling into the remit of medical applications, the FDA – among other regulators – has worked to provide information and guidance to navigate this area of technology. We uncover that UV-C radiation is only effective at inactivating airborne virus and bacteria when exposed directly.
What we know so far:
|Does UV-C light disinfect?||Yes!|
|What is the key to UV disinfection?||Proper UV wavelength band and dosage|
|What spectrum of fluence (UV-C light dosage) most effectively inactivates pathogens?||Specifically, a 240-280nm wavelength band|
|How do we maintain efficient UV-C wavelength band and energy?||Direct and uniform UV light exposure|
So how do we optimize for direct and uniform UVC light exposure?
Before we go any further, visit our on-demand technical webinar on UV Air Disinfection to understand the technology behind this concept.
High-performing UV-C air disinfection equipment is dependent on the reflectivity of the reaction chamber, the light expressed around all surface areas within the chamber (regardless of direct or indirect LED bulb exposure), and a uniform exposure to eliminate hot/cold spots.
But, with various reaction chamber materials types, using the right one can have a dramatic effect on the UV-C dosage, thereby reducing the disinfection chamber device efficiency to airborne pathogens.
In an article published this year in NIST (Journal of Research of the National Institute of Standards and Technology), a practical method using photochromatic indicators as a proven tool for dose validation was used to compare between different reflective media commonly seen in UV-C disinfection equipment. It found that microporous PTFE as a material type is up to 4x more effective than polished aluminum foil for optimizing UVC exposure.
Comparison of Reflective Properties of Materials Exposed to Ultraviolet-C Radiation
|Commonly used reflective media materials||Reflectivity||Difference from direct / indirect exposure||Uniformity of exposure|
|Microporous polytetrafluoroethylene (POREX Virtek® PTFE)||Highest||Minimal||yes|
|Polished Aluminum Foil||Medium||Significant||Prone to localized hot/cold zones|
|White acrylonitrile butadiene styrene (ABS)||Lowest||Significant||None|
(black aluminum foil)
Using microporous PTFE
Using POREX Virtek® PTFE to line reaction chambers in UV-C disinfection devices will:
- Ensure uniform exposure to all areas of the reaction chamber to eliminate hot/cold spots
- Provide no differentiation of light dosage and exposure in both direct and indirect light – typically caused from one LED bulb
- Intensify UV fluence, which eliminates the costly need for multiple UV-C light sources or reduces energy consumption needed to overcome challenges of indirect light spots within reaction chambers
Catch up on your knowledge for reflectivity with our demo videos on YouTube:
UV-C Air Disinfection Chamber Demonstration Porex Virtek PTFE vs Aluminum & Plastic
I’m so proud to say that our POREX Virtek® PTFE makes the world safer, healthier and more productive by setting a new standard of efficacy in disinfection equipment designed to inactivate airborne pathogens. Our reflective media helps to ensure these disinfection chambers are delivering the proper amount of UV-C energy to every nook and corner. Visit our Markets section for more information about our UV Reflective Media solutions.