QUV/uvc Part I: What is the QUV/uvc and why was it developed?

The QUV/uvc is a new version of the QUV accelerated weathering tester. The main difference between it and other QUV models is that it is designed to operate UVC lamps, which are functionally identical to those used in ultraviolet germicidal irradiation (UVGI) applications. These lamps emit about 90% of their light energy between 250 and 280 nm, which is in the UVC range, and almost all of that is concentrated at a single spectral line at 254 nm.  Also called low-pressure mercury lamps, UVC lamps are identical to fluorescent lamps, except there is no phosphor coating inside the glass tube to alter the spectral output of the 254 nm spike.

UVC lamp technology has been in use since the 1950s or earlier to disinfect air, water, and solid surfaces. DNA and RNA chemically break down under exposure to UVC energy, which makes it a very effective tool for deactivating viruses, bacteria, and mold spores.  Not surprisingly, interest in this technology increased in 2020 as a result of the COVID-19 pandemic. UVGI devices have become increasingly popular for disinfecting rooms and other surfaces in medical facilities, aircraft, and public transportation vehicles. Other UVGI systems are being used in HVAC systems or special light fixtures to reduce pathogen concentrations in indoor air.

However, an important question arises. If UVC energy can chemically break down DNA, what does it do to synthetic materials such as paints or plastics? Will the materials in a room, aircraft, or other transportation vehicle degrade when exposed to repeated UVGI cleaning cycles? How will PPE materials hold up to UVC disinfection? We know that UVA and UVB irradiance cause damage to a range of materials, and UVC irradiance consists of even high-energy photons, so this is a very relevant topic.

This is indeed the question the QUV/uvc was designed to help answer. For generations, material scientists and engineers have relied on the QUV to determine how durable their materials are when exposed to natural light. Now, they can use the same technology to test their materials against today’s UVC disinfection systems.

Other than the lamps, what is different about the QUV/uvc?

There are three main differences:

1. The QUV/uvc uses different onboard sensors to detect UVC wavelengths for accurate measurement and control of the irradiance and UVC dose. Although many UVGI devices could, in theory, be used to expose materials for durability studies, few have the ability to operate at specific irradiance levels and continuously monitor and control at that level.
2. Since UVC exposures are not intended to simulate natural weather conditions, the water delivery functions have been removed to streamline chamber operation and maintenance.
3. An increased focus on user safety. Although all QUV chambers have safety features to prevent significant UV light exposure by the user, the QUV/uvc takes this to the next level. The safety features prevent even minimal exposure to UVC light by the user. 

A Series: Testing Durability of Materials Exposed to UVC Light

You are reading Part I.
Read Part II.
Read Part III.
Read Part IV.