What is UVC?
UVC is ultraviolet light generated in the 200-300nm frequency range. This range of light is filtered out by the Earth’s atmosphere and does not reach the surface.
How does UVC disinfect surfaces?
UVC disinfects by disrupting the DNA and RNA in the cells or virus. This stops the cell or virus from replicating and renders it unable to cause or spread infection.
How far away with UVC work from the fixture? How large of an area will it disinfect?
Using the B Direct unit as an example, it can roughly disinfect 230-square-feet from an eight-foot distance. Further distances increase the area of disinfection but lowers the power of UVC reaching the surface. The trade-off is a longer run time to achieve the recommended dose of UVC. This generally adds a few minutes to the calculation.
How long does it take to work?
An operating time of 15-30 minutes should be enough for most applications. Distance and required dosage can fluctuate this amount of time.
Can humans work under the UVC lights?
No. UVC is harmful to humans. It is not the kind of UV light that will give you a tan. Brief, non direct exposure to UVC, especially at a distance, will not represent any lasting harm. However, it should always be avoided. If a human was three feet away from a B Direct II the maximum dosage would be about 45 seconds. That is the recommended dosages for a single 24- hour period.
What safety features do these fixtures have?
The B Air is an enclosed system that can run in the presence of humans and animals. There is no way for the bulbs to be seen while this unit is running. It is safe for 24-hour running in an office or lobby.
The B Direct series has three safety features that are standard and fail safe. There is an audible alarm and a visual light blinking while the unit is running. The motion sensor on the unit will also cut the power to the unit if anyone comes in range. Each unit has a motion sensor built in and more can be added to the system if needed. If any of the safety features fail the unit will not power on until it is serviced.
What does UVC do to the surfaces it disinfects?
Long exposure to UVC light will deteriorate cheaper plastics. White foam and low-density foam like packaging material is susceptible to deteriorations. This is the same as leaving something out in the sun for a year. Acrylic plastics and others are developed to be UV resistant. But long-term exposure is not required to disinfect the surface. These units would only operate in measured minutes not years. They are not required to run for longer than the calculated dosage.
How often do the lamps need to be replaced?
Philips recommends replacement annually but calculated run times can give a more accurate recycling timeline based on the required dosage. Heavy usage might need replacement twice a year. Philips rates the lamps at 9,000 hours with 90% efficiency. However, the number of times the lamp is turned on and off can impact this. Paper strip testing kits for UV dosage will eventually be available to measure the efficiency of the bulbs on the system.