Safety Tips for Using Germicidal Lamps

What Are Germicidal Lamps?

Using a UV germicidal lamp
Germicidal lamps, including a UV germicidal lamp for home, emit radiation in the UV-C portion of the ultraviolet (UV) spectrum that includes wavelengths between 100 and 280 nanometers (nm). The lamps are used in a range of applications where disinfection is the primary concern, such as air and water purification, food and beverage protection, and sterilization of sensitive tools like medical instruments.

Germicidal light, such as that used in handheld UV light sterilization devices, destroys the ability of bacteria, viruses, and other pathogens to multiply by deactivating their reproductive capabilities. The average bacteria may be eliminated in 10 seconds at a distance of 6 inches from the lamp. The wavelength with the greatest effectiveness is 253.7 nm that defines the germicidal lamp category with an optimized wavelength for maximum absorption by nucleic acids. Germicidal lamps that produce energy wavelengths shorter than 250 nm (particularly 185 nm) are very efficient in producing ozone, which is needed for certain applications to oxidize organic compounds.

Hazard and Risks from Germicidal Lamp

UV Radiation UV radiation (UVR) used in most germicidal bulbs and handheld UV sterilizer devices may be harmful to both skin and eyes, and germicidal bulbs should not be used in any fixture or application that was not explicitly designed to avoid exposure to humans or animals. UVR is not felt instantly. The user may not realize the danger until after the exposure leads to damage.

Symptoms typically occur within 4 to 24 hours after exposure to UV light. The effects on the skin are of two main types. That is acute and chronic. Severe effects appear within a few hours of exposure, while chronic effects are long-lasting and cumulative and may not appear within a few years. An acute effect of UVR is the redness of the skin called erythema that may appear similar to a sunburn. Chronic effects of exposure to UV light include accelerated skin aging and skin cancer.

Use of Germicidal Lamps

UV sterilizer devices
UV light has been used in research laboratories as an effective germicide and virucide for most vegetative organisms and viruses. Even though it is used for disinfecting the interior surfaces of biosafety cabinets (BSCs) before and after use, UV does not penetrate well and will only disinfect the outer surface of any material stored in a BSC.


The UV light used in handheld UV light and installed at the ceiling level in some laboratories is used for air and surface disinfection. It is used secondarily to ventilation controls such as directional airflow, dedicated exhaust, and increased air exchanges.

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