UV-C Questions & Answers from UV Resources
1. What is UV-C?
UV-C is one of many electromagnetic frequencies emanating from the sun. Like other of these waveforms, its properties are unique to its wavelength.which is 253.7nm. The "C" frequency of the electromagnetic UV family has, amongst other things, germicidal effects. This was so important that Westinghouse quickly commercialized "germicidal" lamp in the early 1930's. Its humanitarian value has had worldwide success since.
2. Is UV-C harmful?
We’re exposed to parts of the UV spectrum daily (A&B) while outdoors but NOT to UV-C as it is absorbed by our Ozone layer.
o UV-C - includes the germicidal wavelength of 253.7nm and is used for air and water disinfection. Human overexposure causes temporary skin redness and a slight eye irritation (LESS THAN LED) , but no permanent damage, skin cancer, or cataracts.
o UV-B - is a narrower but more dangerous band of UV. Prolonged exposure has been associated with skin cancer, skin aging, and cataracts (clouding of the lens of the eye).
o UV-A - is more predominant outdoors than the other two. It helps to tan our skin and is used in medicine to treat certain skin disorders. It is generally a harmless wavelength.
Generally, UVA is least harmful; UVB contributes to DNA damage and cancer. It penetrates deeply but does not cause sunburn. Because of no reddening (erythema) it cannot be measured in SPF testing. There’s no good clinical measurement of UVB blocking, but it is important that sunscreens block both UVA and B.
UVC however, penetrates superficially and has not been associated with long term tissue effects.
3. How does UV-C kills germs?
Microorganisms are simple organic structures that readily absorb the UV-C wavelength, causing photo-disassociation (destruction). A microbes DNA (deoxyribonucleic acid, is first to be adversely effected due to its weaker molecular bonds. In hundredths of a second it suffers irreparable damage. The subsequent loss of genetic instructions causes cell death and/or the inability to replicate, rendering them harmless. Continuous exposure causes uninterrupted degradation, such as the sun does, only significantly faster. Click here to read more
4. Does UV-C work?
Yes, scientific and anecdotal references abound for UV-C’s efficacy both in literature and in reports of field applications. Of the government reports, NIOSH, OSHA, CDC, GSA, EPA are the most notable. Science in the public forum comes from the University of Cincinnati, Tulsa University, University of Colorado and McGill University (Canada) to name a few. The two labs conducting independent testing and showing very favorable results are ARTI and Battelle. The list of prestigious field studies are too numerous to mention. UVC is used worldwide, more in other countries per capita than in the US. Much of this broader use is for the disinfection of drinking water and treatment of sewage in waste water treatment.
5. What does UV "C" or UV "GI" mean? The letters "UV" relates to the magnetic wavelength spectrum known as UltraViolet light. This spectrum is more often broken down into four categories: Vacuum, Short Wave, Middle Wave and Long Wave’ or VUV, UVC, UVB & UVA. UVC is the frequency that is the most germicidal and the term UVGI refers to "Ultraviolet Germicidal Irradiation" as used by Federal Agencies such OSHA, NIOSH, GSA, EPA and the CDC when referring directly to UVC.
6. Do UV-C lamps produce ozone?
No, but UVC does provide exceptionable conditioning of the air much like the sun does outdoors. UVC fixtures are an air conditioning component that’s in addition to other system parts. Those include the filters, coil, heating core, fan, dampers, humidifiers, etc. All are designed to provide a specific function in the job of processing air for occupied spaces.
7: Can I put UVC fixtures in my home?
Yes - ultraviolet fixtures from Bluhue tech can be safely used in homes, as well as in hospitals, laboratories, clean rooms, doctors″ offices, commercial buildings, food processing plants and other commercial and residential environments - any place a concern for clean air exists.
8: Do germicidal lamps kill viruses?
Yes -germicidal UVC lamps kill up to 99.9% of most viruses, airborne bacteria and mold spores.
9: Will germicidal UV take care of mold?
Yes. Germicidal UVC lamps will kill up to 99.9% of mold and help prevent future mold growth.
10: How often do the lamps need to be replaced?
Germicidal UVC lamps from Bluhue tech are good for approximately 9,000 hours (1.5 years) of continuous use, with only 20% decrease in output over the two years.
11: Should UVC lamps be cleaned?
Yes - depending on the surrounding environment, UVC lamps should be checked periodically (approximately every three months), and can be cleaned with a dry cotton cloth or paper towel. Wear rubber gloves and clean with alcohol only. This will also help maximize lamp life.
12: How much intensity do I need to kill certain organisms?
The exposure of germicidal ultraviolet is the product of time and intensity. High intensities for a short period and low intensities for a long period are fundamentally equal in lethal action on bacteria. The inverse square law applies to germicidal ultraviolet as it does to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp in an Bluhue tech Germicidal Fixture.
13: How hot do the lamps get?
Germicidal UVC lamps do not produce much heat - about the same as fluorescent lamps.
14: To be effective, how close to the surface do the lamps need to be?
The exposure of germicidal ultraviolet is the product of time and intensity. High intensities for a short period and low intensities for a long period are fundamentally equal in lethal action on bacteria. The inverse square law applies to germicidal ultraviolet as it does to light: the killing power decreases as the distance from the lamps increases. The average bacterium will be killed in ten seconds at a distance of six inches from the lamp.
15: What effects does UV light have on surrounding materials?
Long-term exposure of germicidal UVC light to plastics will shorten the shelf life of the plastic by approximately 10%. Example: If the plastic would normally last about ten years, and it's exposed to germicidal UVC light the entire time, it would probably need to be replaced in 9 years. Plant life may be damaged by direct, or reflected, germicidal ultraviolet rays. Transient dyes and colors may be faded from prolonged exposure to ultraviolet rays.
16: Can germicidal UVC penetrate surfaces or substances?
No - germicidal UVC sterilizes only what it comes in contact with, the UVC light will stop when it hits these fixtures. This may require additional fixtures placed strategically in the room to ensure complete coverage.
17: How do you determine the square footage that one germicidal UVC lamp will cover?
This is determined by the wattage of the lamp. Example: A 15-watt lamp will cover approximately 100 square feet; a 30-watt lamp will cover approximately 200 square feet.
18: What safety precautions should be taken when using germicidal UVC?
In personal protection applications (the use of lamps for room irradiation in homes, schools, offices, etc.), indirect fixtures such as TB and Corner Mount fixtures are mounted above eye level. Only the upper air is irradiated and persons or animals occupying the area receive no direct exposure. Direct ultraviolet irradiations, such as Bluhue tech’s Utility Fixtures or Deluxe Surface Mounted Fixtures, irradiate the air in the entire room. In such installations, most of our devices are sensor controlled and will stop when a person or a pet walks past.
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