Please click on any of the questions below for answers to frequently asked questions about UVC sterilization. Of course we also welcome phone calls and e-mails regarding these, and any other questions you may have. Please visit the contact page for individual numbers and addresses of American Ultraviolet associates in your area.
Can I put UVC fixtures in my home?
Do germicidal lamps kill viruses?
What is UVGI and how does it work?
Can Ultraviolet Light Kill Coronavirus (Caution Required)?
Will germicidal UV take care of mold?
How often do the lamps need to be replaced?
How much intensity do I need to kill certain organisms?
Can germicidal lamps be turned on and off continuously?
To be effective, how close to the surface do the lamps need to be?
Do I need ozone-producing lamps?
When do I need to use ozone-producing lamps?
What damage will the lamps do to me?
What effects does UV light have on surrounding materials?
Can germicidal UVC penetrate surfaces or substances?
How do you determine the square footage that one germicidal UVC lamp will cover?
Do the lamps need a ballast to work?
How are UVC lamps used to disinfect the air?
Why doesn't the government, or insurance companies, reimburse for UVC fixtures?
What safety precautions should be taken when using germicidal UVC?
Q: Can I put UVC fixtures in my home?
Yes - ultraviolet fixtures from American Ultraviolet have been 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 throughout the world - any place a concern for clean air exists.
Q: Do germicidal lamps kill viruses?
Yes -germicidal UVC lamps kill up to 99.9% of most viruses, airborne bacteria and mold spores.
Q: What is UVGI and how does it work?
Ultraviolet (UV) energy is a portion of the electromagnetic spectrum. The electromagnetic spectrum is the range of all types of known electromagnetic energy (also known as electromagnetic radiation). The term radiation simply means energy that travels and spreads out as it travels. Read Full Answer.
Q: 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.
Q: How often do the lamps need to be replaced?
Germicidal UVC lamps from American Ultraviolet are good for approximately 17,000 hours (two years) of continuous use, with only 20% decrease in output over the two years.
Q: 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.
Q: 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 American Ultraviolet Germicidal Fixture.
Q: Can germicidal lamps be turned on and off continuously?
There are three common types of germicidal UVC lamps:
"Cold Cathode" lamps are instant-start, using a large cylindrical cathode instead of a coil filament, so lamps have a long life that is unaffected by frequency of starting.
Q: How do germicidal lamps kill?
Ultraviolet light in the germicidal wavelength - 185-254 nanometers - renders the organisms sterile. When organisms can no longer reproduce, they die. To learn more please visit the Basics of UVC section within the Overview section.
Germicidal UVC lamps do not produce much heat - about the same as fluorescent lamps.
Q: 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 in an American Ultraviolet Germicidal Fixture.
Q: Do I need ozone-producing lamps?
Some Germicidal UVC lamps produce ozone. Whether or not you need ozone-producing lamps depends on your particular application. Most of the time you do not need ozone, unless there are shaded areas that the UVC light cannot reach, and the space will not be occupied by people. Ozone can travel in the air to where UVC cannot reach directly, but should not be used in spaces where people will be present, without proper PPE. American Ultraviolet only uses ozone-producing germicidal UVC lamps when specifically required by unique applications, or customer requirements. American Ultraviolet standard UVC lamps do not produce any ozone. Our lamps only emit from 240NM and up.
Q: When do I need to use ozone-producing lamps?
Certain germicidal UVC lamps can generate energy at 185 nanometers, as well as 254nm. The 185nm wavelength produces abundant amounts of ozone in air. Ozone is an extremely active oxidizer and destroys microorganisms on contact. Ozone also acts as a deodorizer. Another advantage is that it can be carried by air into places that UVC radiation cannot reach directly. American Ultraviolet standard UVC lamps do not produce any ozone. Our lamps only emit from 240NM and up.
Q: What damage will the lamps do to me?
Prolonged, direct exposure to UVC light can cause temporary skin redness and eye irritation. American Ultraviolet systems are designed with safety in mind and, when properly installed by a professional contractor, do not allow exposure to ultraviolet irradiation and allow for safe operation and maintenance. If you are exposed to direct germicidal light, it can burn the top surface of your skin. If your eyes are exposed, it would be similar to a "welder's flash", and your eyes can feel dry or gritty. At no time do germicidal lamps cause any permanent damage.
Q: 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.
Q: Can germicidal UVC penetrate surfaces or substances?
No - germicidal UVC sterilizes only what it comes in contact with. If you have a room sterilizer, such as one of our TB models, and there are light fixtures or fans hanging from the ceiling, the UVC light will stop when it hits these fixtures. This may require additional fixtures placed strategically in the room to ensure complete coverage.
Q: 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.
Q: Do the lamps need a ballast to work?
Yes - a germicidal lamp is one part of a system, and the system cannot be fully defined and optimized unless the lamp and ballast combination is determined. It is the interaction of the lamp and ballast that is the true determinant of system performance.
Q: How are UVC lamps used to disinfect the air?
Germicidal UVC lamps can be used in ceiling fixtures suspended above the people in a room, or within air ducts of re-circulating systems. The first method is called Upper Air Irradiation. The fixtures are shielded on the bottom so that the radiation is directed only up toward the ceiling and out the sides. These upper-air germicidal fixtures are mounted at least 7ft. above the floor so that people will not bump into them or look directly at the lamps.
The second method of air disinfection uses UVC lamps placed inside the ventilation system ducts. If a ceiling is too low for an upper-air irradiation fixture, this type of an in-duct germicidal fixture can be used. Also, because people are not exposed to the UVC radiation, very high levels can be used inside the ducts.
Q: Why doesn't the government, or insurance companies, reimburse for UVC fixtures?
Germicidal lamps were not placed on the Medicare or Medicaid list when the government requested it in the early 60s, because tuberculosis was not a major issue at that time. Because it's not on these lists, the government, and insurance companies, will not reimburse individuals for purchasing a UVC system.
Q: 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 American Ultraviolet's Utility Fixtures or Deluxe Surface Mounted Fixtures, irradiate the air in the entire room. In such installations, personnel should be protected by wearing either goggles or face shields, such as American Ultraviolet's Ultra-Spec 100 Safety Goggles and Ultra-Shield Face Shields designed for ultraviolet exposure, and by covering as much skin as possible with clothing or sun block.