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Disinfection Update - November 2020

What is a Shadow Area when referring to mobile UVC devices?

UVC Dosimeter cardsWhat is a shadow area? It is an area that is not in direct line of sight of UVC disinfecting energy, and can simply be described as the backside of an object. When placing a mobile UVC device in any environment there will always be a so-called shadow area that will receive much less UVC, since it will mostly reach the area from reflection; hence, it will be less disinfected, if disinfected at all. Ideally, shadow areas should be avoided as much as possible.

To help minimize shadow areas, try to place the mobile device in more than one location to be sure to "hit" the important areas, which most often are high touch points on chairs, bed rails, door handles, tray tables, phones -  really all objects that are frequently touched by persons.

Some manufacturers recommend a single position, and claim to disinfect shadow areas. By definition an area is a shadow area that does not receive the same intensity of UVC energy as an area in direct line of sight. This typically results in longer run times, which can be a limiting factor in using a mobile device – because time is money! And short turn-around times are critical. Hence it is more efficient, and effective, to run quick multiple cycles in various locations to limit, or eliminate, any shadow areas.

To help assess if an area has received the desired dosage of UVC, Dosimeters can be placed in those areas to validate that the desired energy level has been reached.

Dosimeter cards are available in:

UVC Dosimeter card

Tri-card label with 25mJ/cm2, 50mJ/cm2, 100mJ/cm2

UVC Dosimeter card


UVC Dosimeter card

MRSA / C. diff.

American Ultraviolet is the exclusive North American Distributor for Intellego Technologies.

Learn more about the American Ultraviolet UVC Dosimeters.

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Visit the Disinfection Update E-newsletter archives (which begin with March 2020) to read helpful stories about the effectiveness of UVC Disinfection.

None of the American Ultraviolet UVC products detailed above are certified, or approved under any applicable laws, as a medical device, and as such, American Ultraviolet, and its Representatives and Distributors, do not currently intend for them to be used as medical devices anywhere globally. Products have not been evaluated by the FDA.