Determine the UV Dose

Determine the UV Dose

Identify the targeted microorganisms along with the desired log reduction.


The UV Dose determines what portion of a specific microorganism is destroyed after a particular fluence of radiation is administered.


Target the UV Dose at 50mJ/cm2 at 3-log reduction to deactivate the average bacteria/virus

Targeted Pathogens – UV Dose (Fluence) for a Given Log Reduction

Below is a screenshot taken from tables that cover a large variety of UV-C targeted pathogens, including spores, bacteria, viruses, and algae. The tables provide the UV Dose, Fluence, for a given log reduction. The complete table listing is available via the link below.

Determine the Required UV Exposure Time

Given that:     Exposure Time = UV Dose / UV Intensity


It is significant to consider the UV Dose to be administered, the UV Intensity of the Light Fixture, and the distance of objects from the light source. The placement of the Mobile Unit, and the number of units to be used are also critical factors.

The following charts provide some guidelines for Exposure Times for both the Handheld and the Mobile Units, at various distances, at a Dose of 50 mJ/cm2.

Validate with Dosimeter Cards

Before disinfecting an area, Dosimeter Cards can be placed on objects and surfaces in order to validate that sufficient germicidal irradiation has been delivered to kill targeted pathogens.


Dosimeter Cards react to UV-C at 254 nm, which is the peak wavelength for germicidal effectiveness, and change colors to indicate the level of UV-C irradiation administered to these surfaces.


Dosimeter Cards are available from one of our partners, American Ultraviolet. The link below discusses how to properly use the cards to verify the amount of UVC exposure administered during a disinfection process. An instructional video is also provided.

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