Posted by Doug Root on 31st Aug 2021

Are All UV Bulbs Germicidal?

You may have heard it said at some point or other that extreme care must be exercised when handling or in the presence of UV bulbs. There is some truth to this - but it depends on what type of UV bulb is the one in question.

Not all UV lights are the same, despite the fact that all of them emit ultraviolet light. There are actually three types of UV light bulbs, classified according to whether they emit UVA, UVB, or UVC light.

In short, not all UV bulbs are germicidal, though many of them are. It’s going to come down to the wavelength of light emitted from the bulb.

UVC Light Bulbs and Their Uses

UVC light (A.K.A. UV-C or UV C light) is the shortest wavelength of UV radiation. It is effectively invisible to the human eye and occupies the range of wavelengths between 100 and 280 nanometers, or nm.

UV light that falls within this range of wavelengths can be extremely hazardous to human health. UVC light can cause significant, extensive burns to human skin and it is also very damaging to human eyes, causing a condition known as photokeratitis. For this reason, you should never expose yourself to a UVC bulb, nor should you ever look directly at one. Even a small amount of exposure can be damaging to skin and eyes, and overall health.

UVC light is not only hazardous to human health. It is also highly damaging to all forms of genetic material, which makes germicidal UV light particularly effective at disinfecting and sterilization. UV radiation causes disastrous, irreversible damage to genetic material. When microbes and viruses are irradiated with UVC, their DNA (or RNA) is damaged, making cellular replication impossible. As a result, the microbes or viruses can no longer reproduce and die.

Even among UV bulbs classified at UV germicidal lights, not all are the same. They may emit a specific wavelength of radiation or several different wavelengths in addition to other forms of light as well. Nonetheless, these types of UV lights are largely put to use for sterilization, sanitation and disinfection, especially in the following areas:

●Disinfection and sanitation of food preparation surfaces.

●UVC light can be used to destroy the virus responsible for COVID-19, SARS-CoV-2.

●Air sterilization, such as Upper Room Ultraviolet Germicidal Irradiation (UVGI), to keep HVAC systems clean and clear. It can also be used to sterilize air purifiers.

●Wastewater treatment and purification systems, since it doesn’t require the use of harsh or harmful chemicals.

●Sterilization of surfaces associated with medical procedures

●Surface sterilization of high-traffic surfaces, such as in restaurants and places of public transit.

●Food irradiation: Irradiating food with UVC light helps inhibit the growth of pathogens and may even help prevent early spoilage.

Despite the far-ranging uses of UVC germicidal lamps, not all UV bulbs emit UVC radiation and therefore have different applications. There are still two other broad classifications of UV bulbs, which are often referred to as blacklight-blue lamps or black lights, and emit either UVA or UVB light.

UVA Light and More Interesting Uses for UV Bulbs

UVB radiation, which occurs in frequencies ranging from 280-315nm, lies next to UVC on the scale. While not as expressly harmful as UVC, UVB light is still implicated in sunburn and can be damaging to skin. Exposure may also be linked to a range of adverse health conditions, such as skin cancer.

It is UVA light, with wavelengths ranging from 315 to 400nm, and closer on the electromagnetic spectrum to visible light, that has more relatively innocuous uses. Exposure to UVA light is not nearly as overtly harmful as UVC light, and UVA light has been widely used in commercial and recreational applications, often known by its more recognizable name, a black light.

Black lights are commonly used for mood lighting in clubs and other places of public gathering, but believe it or not, blacklight actually has some more practical applications, including but not limited to the following:

●Black lights can be used to detect the efficacy of sanitation procedures or protocols, as different forms of human and animal waste will glow under a black light. They can also be used to detect pet stains.

●Black lights can be used to detect leaks in mechanical and industrial systems, as many vital fluids are treated with a tracer that glows under a black light.

●Black lights can be used to detect forgeries of banknotes or counterfeits of art.

These are only a few of the many potential uses for black lights, the practicality, and applications of which vary significantly from UVC bulbs. If you have any further questions about the differences between the several types of UV lights or would like to learn more about how UVC lights can be used to enhance and improve sterilization procedures, please feel free to contact us at 888-988-2852.