At a recent tanning trade show, several attendees asked Team Wolff about UV meters. Here is some basic information about a tool every salon operator should have.
A handheld UVB/UVA meter is an excellent tool for your purpose. This type of meter gives you an indication of a lamp’s total UV output, and while not as accurate as expensive precision testing gear, does allow you to track decline in UV output over time in a narrow fashion.
The meters are not accurate enough to compare different beds with each other, or different lamps with each other. This is due to the spectral character of the tested product in relation to the sensitivity of the meter at specific wavelengths. Also, when you try to compare one set of sunbed/lamp data with another, you are actually looking at results from many variables other than lamps, such as the bed geometry, lamp density, distance from the lamps to the tanner during a session, acrylic solarization, etc.
Ideally, you should test a sunbed/booth’s output after re-lamping it. Warm the unit and lamps for 15 minutes, and always test at the same time of the day. This is so that variables, such as heat build-up, are as close to the same conditions as possible from test to test. You should consider doing all meter-reading after the first 15 minutes of each test day. Record your “zero hour” readings, then meter again every 100 hours and compare to the original readings.
Over time, a sunbed’s acrylic shields degrade due to exposure to UV light. The acrylic’s ability to allow UVB to pass through diminishes more rapidly than UVA transmission. Most acrylic shields transmit 94-96% of the UV when new, but as they age (2,000-5,000 hours), the effectiveness will decrease, with emphasis on reduced UVB transmission. This degradation of the acrylic material is a process known as solarization. To measure the transmissive quality of acrylic shields, a UVB meter is better than one that measures for UVB/UVA. Meter without the acrylic, then with the acrylic in place. If there is a significant difference, it’s time for a new acrylic. Because sunlamps emit predominantly UVA, and acrylic solarization most significantly affects transmission of UVB, the UVB/UVA meter will not give you accurate enough data to protect your business from “no tan” complaints due to acrylic solarization.
Do not rely upon the lamp manufacturer’s life expectancy claims; when UV output declines by 25-30%, replace your lamps before you get complaints from tanners about unsatisfactory results. ν
While not as accurate as expensive precision testing gear, a UV meter does allow you to track decline in output over time in a narrow fashion.
