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UV Light Testing
Verify that UV Light is Real

When you're using a UV-C light for disinfection, you want to know that it's working. With hundreds of models being sold and no national certification system, you're mostly on your own. Fortunately, there are four ways to verify what you bought is the real deal.

Light Meter

The first and most thorough method is with a UV Light Meter. These are handy little electronic devices that measure the exact UV-C light intensity of anything that uses UV light. An example of that is the Sper Scientific Direct UV Light Meter UVC - 850010.

You can find that at the link here: https://www.sperdirect.com/uv-light-meter-uvc-286-prd1.htm

There's just one problem. These units typically cost almost $800 each, far more than what most people are spending on UV gadgets. These are great for corporate settings but impractical for the home user.

Sper Scientific Direct UV Light Meter UVC - 850010
Sper Scientific Direct UV Light Meter UVC - 850010.

Photochromic Measurement Cards - Single-Use

The second option is a card that changes color and indicates dosage levels when exposed to UV-C light. These are called photochromic UVC measurement cards.

They're relatively inexpensive, running about $5 a card. The way they work is that you put a card at each high-touch location you want to check. Then leave the room and run the disinfection cycle.

The card will change color, indicating the amount of UV-C exposure it received. If it didn't change to the right color, you know you need to expose that area to a more extended dose or move the machine closer.

The problem with these cards is that they're single-use. After you've used it once, you can't do it again. But for small businesses that just want to make sure they're properly disinfecting surfaces, these are a reasonable option.

We like the cards made by American Ultraviolet at this link here: https://www.americanultraviolet.com/germicidal-healthcare-solutions/

Photochromic Measurement Cards by American Ultraviolet
Photochromic Measurement Cards by American Ultraviolet.

Testing UV-C Lamps with Dosimeter Card

We ran the lights for 30 minutes, just 6 inches away from the dosimeter cards. A card that hasn't been exposed to UV-C light will have a yellow center. As the light runs, the center will change color and darken to show the level of exposure.

The first lamp we tested was a WTL UV Germicidal Lamp, and it was REAL. You can see in the picture and the time-lapse video, the card definitely darkens and shows that it's working. We did additional tests using the light on germ covered surfaces, and we measured how effective it was at sanitizing. It performed well.

The second lamp we tested was the "2020 Newest UV Light Bulb E26/27" sold by New Sunshine on Amazon. That lamp was FAKE. We ordered two, and they were BOTH fake.

There was NO change in the color, even though the lamp was just 6 inches away and it ran for a full 30 minutes. We can only assume all the lamps of this model and/or sold by New Sunshine on Amazon are also FAKE.

You can see pictures and videos of both tests below. Stop the videos right at the end, and you can see when we hold an unexposed card up to the exposed card. The real lamp changed the color of the card; the fake one did not.

Real UV-C Lamp


How to Use Dosimeter Cards

Photochromic Verification Cards - Multiple Uses

The third option is cards that simply change color when exposed to UV-C lights, but they don't tell you the dosage levels.

The cards run about $15 after shipping. You place the test card in the area that's supposedly exposed to germicidal UV-C light. If a UV-C lamp is running, the letters UVC will appear in green on the card.

It's reasonable to combine a multiple-use card like this to verify you've got a UV-C light, along with a Photochromatic Measurement card to verify exposure levels.

We like the QuantaDose™ UV/UVC INTENSITY CARD available here: https://www.quantadose.com/


The Banana Test

The fourth option is the banana test. Put what you believe is a UV-C light up close to the banana. Mark off a strip of the banana with duct tape, then let the light shine for 15 minutes. When you peel the tape away, you should see a clear line where the light has "tanned" the banana. If the banana skin hasn't darkened, you probably have a fake UV-C light.

The video below shows how this works.

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On-site testing in Key West,
give us a call at (305) 294-7928.
The staff at WeBeFit will answer
and they can schedule your consultation.