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So, what are UVB percentages and what do they tell you about lamp performance?
There isn’t an industry standard for determining a lamp’s UVB output, just as there is no industry standard for determining the “tingle factor” of a tanning lotion. For example, a product designated Tingle Factor 30 from Company A may perform completely differently than a Tingle Factor 30 from Company B. However, you know within the lotion lines from Company A that their 30 is stronger than their 20, and the same goes for Company B; but, you can’t compare Company A’s tingle to Company B’s tingle.
It’s basically the same concept with tanning lamps. The UVB ratio is just a number that sunlamp manufacturers use to market their products. A UVB percentage number is reached by dividing a sunlamp’s measured amount of UVB energy by its UVA energy. This is a common method of “rating” sunlamps; but it is only a relative figure and tells us very little about the tanning power, effectiveness or useful life of a given lamp. It is not an accurate measure of a lamp’s true performance.
Exposure to UVB radiation is a critical component for the production of melanin in human skin, which is then darkened by exposure to UVA. The determining factors in a sunlamp’s performance are the total amount of UV energy, and whether the UVA and UVB are from the most effective spectral regions.
Two sunlamps are shown in this simple graph. Both deliver the same amount of UVB energy, but emit greatly differing amounts of UVA. The lamp on the left (1) has a 5% UVB ratio versus the on the right (2) with only 4%. If one only looks to the UVB% values, Lamp 1 with its higher UVB/UVA ratio could mistakenly be construed as a stronger or more effective lamp. Not true; Lamp 2 has a lower UVB ratio because it emits so much more UVA.
An effective sunlamp must produce a balance of both UVA and UVB. Adding more UVB typically creates a lamp that delivers more skin “reddening,” but is not a better “tanning” lamp.
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Michael Stepp joined Wolff System as President in 1998, bringing years of lighting industry experience with GTE Sylvania, Osram Sylvania and Philips. Married for 38 years, he has a daughter and granddaughter.
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