Tanning Lamp Maintenance Lamps show the highest decline in their output performance during the first 100 hours of operation. For this reason, some manufacturers define their lamps nominal output performance after 100 hours of operation.

The drop in power between zero and 100 hours generally amounts to about 10 percent to 20 percent, depending on the properties of the phosphor used inside the lamp. Most of the published maintenance curves were obtained with "free burning" lamps under optimal operating conditions. Therefore, the actual decline in output of lamps in tanning units often differs significantly from the corresponding declarations.

A definite recommendation cannot be given, however, as a rule, lamps should be replaced when they reach a decline of 70 percent of their starting performance. In other words, the decrease in power should not exceed 30 percent. This basic rule will assure the tanning effectiveness of your lamps over their "useful life."

There are two different classes of phosphor available for tanning lamps. One type is used in standard tanning lamps and shows a stronger decline in performance, recommending replacement after about 300 hours to 500 hours of operation. Another type of phosphor is considerably more expensive and largely used in the professional market of tanning lamps. The gradual decline in performance of these lamps extends their useful life up to 800 to 1,000 hours.

The best way to monitor the decreasing output performance of tanning lamps to determine the right time for replacement is to use a pocket-sized UVA meter. Generally, a UVA meter of this kind is not suitable for measuring the absolute UVA irradiance of tanning lamps with different emission spectra. Showing a relative measurement of irradiance tells the age of lamps. The UVA meter is easy to use, if certain steps are followed:

• Take an initial reading upon the installation of new lamps.
• Make sure the measuring conditions always are kept the same. Measure at the same location of your tanning unit, at the same distance and observe the same electrical conditions for each single measurement.
• Make sure that the acrylics and reflectors are clean. It is imperative that acrylics are changed according to the manufacturer's specifications.
• Wait for your measurement until your tanning unit is in a state of "thermal equilibrium," which takes about 5 minutes to 10 minutes after turning it on.

If these steps are followed, measurement readings for comparative purposes will be obtained. Pocket-sized UVA meters are used to measure UVA values. Although these meters only register UVA levels, it can be assumed that the UVB values will diminish by approximately the same relative amount.

Equipment-Related Factors

The total operating time of the lamps is probably the most important factor determining output performance. However, some additional factors stem from the tanning unit used and how well it is functioning.

Equipment related factors such as dirty or dusty reflectors will reduce power. They can be avoided by regularly cleaning your equipment. Other factors include the permeability of the acrylic cover and the cooling system.

Make sure to check that the reduction of irradiance is not due to insufficient permeability or penetration of the acrylic sheet. Simply use your UVA meter and compare the readings made with and without the acrylic sheet.

Acrylic care is probably the most overlooked element to tanning bed maintenance. It must be noted that it is essential to optimize lamp performance through the use of acrylics that allow for proper transmission of UV energy.

If UVA readings obtained with the acrylic sheet on the tanning unit are more than 20 percent lower compared to those without the sheet, you probably have an aging acrylic sheet that acts as a filter. Additionally, yellowing of the cut edges on acrylics indicates it is time to replace the acrylic sheet. It is important that the acrylics be changed with the manufacturer's specifications.

As is generally known, a lamp can provide maximum power only if it is operated within an optimum temperature range that is approximately 108 degrees Fahrenheit. If the temperature is too low or too high, it will lead to a drop in output. To check whether the cooling system of your unit conforms to the optimal operating conditions of the lamps, the following procedure can be recommended.

During the warm-up phase of approximately 30 minutes after switching on your unit, constantly record the UVA irradiance by use of a UVA meter. The best readings will be obtained in the center of the tanning area. If the reading becomes steady at maximum UVA values, it can be assumed that the cooling of the unit is proportioned correctly.

On the other hand, if the measured values pass through a maximum before settling at a lower reading, the flow of cooling air is probably too weak. If there is a constant rise, in the readings throughout the entire warm-up phase, but without a noticeable maximum being obtained, this should be interpreted as a sign that the unit may be over-cooled. Such problems can be adjusted if the unit allows you to change the cooling air flow. If not, contact the manufacturer of the unit.