UV Lamp Systems – A Glossary

There are so many technical terms used to describe UV lamp systems for disinfecting room air, air streams and in-duct component surfaces. With feedback from our customers, we’ve uncovered that it can be quite difficult to navigate the right UV bulbs for your needs. So we’ve come up with a handy glossary of terms to help you out when deciding which brands and products to choose from.


This stands for Ultraviolet Germicidal Irradiation. Confusingly, it’s often used interchangeably with the term UVC. UVGI describes the use of radiation to kill or inactivate organisms. UVGI is the radiation generated by UV germicidal lamps that makes organisms inactive, either by killing them or making them unable to reproduce. UVGI lamps are most effective if they emit radiation at a wavelength of 253.7nm UVC refers to ultraviolet radiation that falls within the range of 100-280nm.

When selecting a UVC lamp, it’s important to ask about the wavelength of radiation it emits because organisms differ in their susceptibility to UV radiation. For example: a UVC lamp that emits a wavelength of 254nm can inactivate bacteria such as Agrobacterium Lumefaciens, moulds like Aspergilius Amstelodami and viruses including Influenza.

A UVC lamp emitting a wavelength of 187nm won’t inactivate those bacteria, mould or viruses – but it will breakdown smells associated with cigarette smoke, formaldehyde and other VOCs.


This is the intensity of electromagnetic radiation on a surface – it’s typically measured in microwatts per square centimetre. The irradiance of your UV lamp and housing matters because it’s one of the factors that impacts how long you need to expose an organism to UVGI in order to inactivate it.

we often confuse irradiance with luminance – it matters because UV is invisible to the naked eye… that blue light you associate with UV light isn’t actually a determinant in the irradiance of a UV bulb…confusing, right? No matter which brand of UV bulb you choose the UVGI output of the bulb will decrease over time.  So, ask your UV bulb supplier a two-fold question a) What is the lifetime of your UV bulb? The answer to this will likely be between 1-2 years. b) What is UV output of the bulb at day 1 and at the end of its lifecycle (day 365 / day 730).