UVC-GI -Ultra Violet Germicidal Irradiation measurements
Not all UVC-GI – Ultra Violet Germicidal Irradiation lamps are created EQUAL.
Assuming a UVC lamp data sheet showed a power consumption of 15W, 55V. UVC output of 4.9W@254nm it is imperative for you to know, that this is a laboratory value.
Meaning: The maximum the lamp theoretically produce under optimum conditions.
- UVC lamps output will reduce overtime due to an internal solarisation effect. The older the lamp gets, the lower the maximum output will be!
2. UVC lamp’s output is dependent to it’s working conditions. “Overheating” are common when you cover the UVC lamp to prevent radiation externally. This will cause a decisive output reduction, as UV lamps (low pressure mercury vapor discharge lamps) are very temperature sensitive.
An ambient air temperature difference of just 1°C to 5 °C will lead to an UV output variation of up to 15%!
3. Appropriate ballast. Not any ballast enlightens the lamp correctly. A wrong ballast will overheat the lamp although blue light is still irradiated. BUT the required UVC output is dramatically below expectations.
4. When the switch is on = UVC power on. It is a low pressure discharge. It takes some time to get to the optimal level of 254nm.
5. NEVER use a fan to cool the UVC lamp. Air flow on the discharge lamp will have an dramatic (negative) impact on the internal gas pressure and thus output goes down considerably
6. Measuring using a UVC radiometer – assure if it is calibrated. Measure at the correct distance between the photodiode. The longer the distance of the UVC LAMP to the UVC radiometer, the results will dropped dramatically.
7. UVC rays are optical rays that can be reflected, bend, absorbed or transmitted, they are not the same throughout.
UVC rays reflect differently and get absorbed differently to light in terms of material values. E.g. UVC rays will get 100% absorbed by plastic, glass or borosilicate. A conventional mirror will reflect visible light by 98% and more, but it won’t reflect any UVC rays.
CONCLUSION
Measure your UVC Devices accurately with UV Cense or a calibrated UVC radiometer.
UVCense dosimeters are the perfect complement to professional UVC disinfecting equipment. A Bluetooth® enabled dosimeter is available for healthcare and commercial applications, permitting a direct connection to UVC disinfection equipment and logging of dose measurements. For permanent applications, our dosimeters snap into wall holders, enabling easy dose verification.
UVCense dosimeters are ideal in our medical office setting. They are sturdy, reliable, compact (fit into most of the smaller UV sterilizing units), extremely easy to use and read, and eliminate the insecurity of not knowing the germicidal efficacy of our UV sterilization devices. I highly recommend them as an integral part of any infection control effort.
UVCense dosimeters are available for sale from Agis Medical Supplies Pte Ltd – call (65)62599788 for more details
Delta Ohm Photo Radiometer HD 2102.2 with calibrated UVC probes LP471UVC
Home test for UVC validity
For Home use, it is possible to verify if the UVC lamp is legit. Just expose the banana to the UVC. The color of the banana skin will get burnt or turn darker after 5-10 mins.
