Posted by Doug Root on 17th Mar 2020

Germicidal UV-C Bulbs - What You Need to Know About Disinfecting & Neutralizing Bacteria & Viruses

Updated March 17th, 2020


In light of the situation with the novel coronavirus, COVID-19, we have received many requests about alternative uses for our UV germicidal lamps. While UV germicidal lamps have been known to effectively eliminate many viruses, airborne bacteria, and mold spores, we are unaware of its effectiveness against COVID-19, specifically. Additionally, UV radiation (UVR) used in most germicidal lamps is harmful to both skin and eyes, and germicidal lamps should not be used in any fixture or application that was not designed specifically to prevent exposure to humans or animals. We cannot stress enough to handle and use UV germicidal lamps as intended, and with extreme caution.

We understand everyone’s concern and need to maintain a sterile environment. We urge everyone to take all reasonable measures possible to disinfect your surroundings, using antibacterial cleaners and sanitizing wipes, as well as the CDC guidelines for staying safe during these uncertain and stressful times. Here is a quick link to the CDC's recommendations to best prepare your household:

We hope this helps everyone navigate through these unprecedented times.

A germicidal lamp is a special type of lamp which produces ultraviolet light (UV-C). This short-wave ultraviolet light interrupts DNA base pairing which in turn causes the formation of pyrimidine dimers which leads to death of bacteria, viruses and protzoa . In air cleaning applications, ozone production is an unwanted by product and ozone can be dangerous when released and not collected. In instances of water purification you will need to use an ozone producing lamp(NM under 253.7). 

NOTE: Germicidal lamps are designed for specific applications and should never be used to make DIY sterilization equipment. 

Low-Pressure Germicidal Lamps

The low-pressure germicidal lamps look just like a standard fluorescent lamp, however they are clear. They have a wavelength of 253.7 nm. Germicidal lamps are used to sterilize tools, surfaces and air in medical facilities and commercial buildings. most popular germicidal lamps are the clear low pressure type from names like PHILIPSLight Emissions TechnologyUSHIOOSRAM. They are clear because they have no fluorescent phosphor coating on the inside of the lamp. These lamps are also made of a different type glass. Most fluorescent tubes are made of standard borosilicate glass however germicidal bulbs are made with a special fused quartz glass. With the glass and no phosphor coating, the 253.7 nm ultraviolet light produced by the mercury arc is passed outside the lamp and used for sterilization rather than general light. 

Germicidal lamps are very common now in sterilization applications. OEM's use these lamps in HVAC equipment, water purification and surface sterilization. You will see that in many of the part numbers they carry the "OF" label which means that the lamp is Ozone Free. It is very important to change your germicidal UVC lamps regularly as the light output dimenishes over time and you may not be killing the viruses or bacteria. 

These lamps are extremely dangerous when viewed by the naked eye or exposed skin. Short-wave UV light is harmful.  It is imperative that these lamps be shielded from human contact. OSRAM Sylvania PURITEC HNS lamps carry these warnings: PURITEC HNS germicidal lamps emit high-intensity UV radiation that can cause sunburn and conjunctivitis. The skin and eyes must therefore not be exposed to direct or reflected unfiltered radiation.

The 2 types of germicidal lamps you will find are linear tubes and compact plug in type.            

Germcidal bulbs

Our most common lamps are listed below, we see these in 75% of applications, these lamps are ozone free:


Mid Range Germicidal Lamps

Mid range germicidal bulbs are not clear like their low pressure counterparts. These lamps produce a 287 nm wavelength and have a special phosphor coating on the inside of the lamp. These lamps produce UV-B light. USHIO produces a few versions of these specialty germicidal bulbs. G6T5/EG8T5/E G15T8/EG25T8/E.

If you are looking to replace your germicidal lamp in an OEM's so with caution. Please make sure the unit is off and you do not look directly at the light. Remove the germicidal lamp and get the part number off the lamp. This will help team find the replacement lamp. The rest is simple, go to and type your germicidal lamp number into the search box!