Island Sun Times

Perhaps a better question would be, “What is the difference between a 10-minute, 20-minute and 30-minute sunbed?”

An indoor tanning lamp’s performance is directly related to the equipment in which it is installed. The same lamp may result in different exposure schedules in various equipment models. Factors such as the transmissive quality of the acrylic shield, the distance of the lamps from the tanner, the ballasts used, bed geometry, electrical current/voltage, number of lamps and the distance between them, and the effectiveness of the sunbed’s reflector system all influence what the exposure schedule and maximum timer interval will be.

By using a “standard” or “typical” sunbed for evaluation, a lamp manufacturer can estimate a lamp’s TE or exposure time. When consistently applied, this method can give you a pretty good idea of what to expect in your application. Given the same sunbed, a “10-minute” lamp will deliver twice the erythemal effectiveness as a “20-minute” lamp. This is usually accomplished by increasing the UVB (280-320nm) and UVA2 (320-340nm) outputs, at the expense of UVA1 (340-400nm). Higher wavelength UVB and UVA2 are most closely associated with skin photoaging (wrinkles), vitamin D synthesis, melanin formation and some pigment darkening. UVA1 penetrates the skin further and contributes to robust pigment darkening and longer-lasting tans.

All tanning units, regardless of timer interval or lamp type may produce a maximum of four MED (minimal erythemal dose). An MED refers to the least amount of UV radiation a person can receive which induces a distinct erythema or “pinkening” of the skin within 7-24 hours following exposure. Always replace lamps with the product that is listed on the tanning unit label or a FDA compatible alternative. A compatible replacement lamp should not change the sunbed’s exposure schedule by more than +/- 10%; therefore, a compatible replacement lamp for a 20-minute bed should have a TE in the 18-22-minute range (10% of 20 minutes is +/- two minutes). Then, use a hand-held UV meter to monitor your lamp’s depreciation and replace when the output drops 30 percent from initial readings.