Safety-Related mesaurements of UV-C Air Disinfection

Measurement of Actinic and Safety-Related Irradiance of UV-C Air Disinfection

App. 012

Shortwave UV-C radiation is highly bactericidal because it is absorbed by the DNA of microorganisms which destroys its structure. Referred to as ultraviolet germicidal irradiation (UVGI), UV-C wavelengths around (260-270) nm are most effective in combating airborne bacteria, viruses and other microorganisms such as mildews and yeasts. Disinfecting the air can prevent the transmission of a variety of airborne infections such as tuberculosis and pandemic influenza. It can also prevent contamination of raw materials and food. Therefore, UV-C air disinfection systems are being increasingly used within healthcare environments, public places, industry, and research facilities.

Requirements for UVC Air Disinfection Measurement Equipment

Manufacturers need to optimise the efficacy of the UV germicidal action of air purification systems whilst ensuring no hazard is presented to occupants. New developments in germicidal UV sources, of particular note are UV-C LED arrays (265-280)nm and far UV lamps such as excimer KrCl (222nm), require new calibration strategies in order to allow low measurement uncertainties. We offer spectral mismatch correction for all used UV sources.

Out specialist UV-C detectors and meters (UVC Radiometers) are designed to withstand the high-energy UV radiation present within air disinfection systems whilst offering the dynamic range to enable low level hazard measurements. To measure the irradiance of such extended sources, radiometers must be designed with a cosine field of view function. The required cosine-correction optics and photodetector components must also be pre-aged because of the high-energy UV radiation. Occupant safety [1] must be ensured for rooms fitted with ceiling-mounted air disinfection systems. The monitoring of exposure to UV-C [2] of long term occupants (e.g. healthcare workers [3]) within rooms fitted with air purification can be achieved with the use of personal dosimeters such as the X2000 dosimeter. For spectral measurements our high end spectroradiometers like the BTS2048-UV can be recommended.

The importance of ensuring personal safety in the presence of UVC-based disinfection systems has also been stated in a report by the German Commission on Radiological Protection [4].

Germicidal UV Standards

See also our application note about available Germicidal UV Standards. This list can give an quick overview about the diversity.

Large Research Project about UV-C Devices

In a large study we have made measurements as a contractor of the Federal Office for Radiation Protection in Germany (BfS). A total of 41 disinfection devices that work with UV-C radiation were tested. Traceable measurements were performed including measurement uncertainty evaluations according to JCGM 100:2008 and JCGM 101:2008 and a conformity assessment according to ILAC-G8:09/2019. For instance, the corresponding risk groups were analyzed according to DIN EN IEC 62471 and evaluation of the framework of DIN/TS 67506 was made. Additionally, some upper air devices were tested according to DIN EN ISO 15858 and finally, DIN EN 60335-2-65 was applied. A comprehensive report with the measurement data and the framework of product standards and laws was published by the BfS [5]. All measurements were performed with our low stray light BTS2048-UV spectroradiometers with OoR Filter method and combined stray light correction matrix and our UV-37 series detectors, see links below.