Straight Talk About Tanning Lamps

Nothing is more important to the success of your indoor tanning salon than using sunlamps that perform well. Based on more than 10 years experience using and testing sunlamps and tanning units, this article provides a unique perspective and insight into the world of lamps. The following are answers to some of the most commonly asked questions we have received from tanning salon owners. 

Q: Does it help to know the UVB percent of a sunlamp? 

A: We respond to this question by asking “percent of what?” This sums up why we believe that the indoor tanning industry should stop using UVB percent as a useful “indicator” of sunlamp performance. For example, if you have two sunlamps with the same “absolute” amount of UVB photons, i.e., 100 W/m^2, and one lamp is rated at 2% UVB and the other has 1% UVB all this tells you is that the 1% UVB lamp has twice as many, i.e., 10,000 W/m^2, UVA photons than the 2% lamp that has 5,000 W/m^2 of UVA. In both cases, the sunlamps have the same erythemal power.

HID/high-pressure tanning equipment may “appear” to have lower UVB percent ratings, i.e., 1% to 2% UVB even though they often have as many (or more) UVB photons than a low-pressure lamp with a 4% UVB percentage rating. This occurs because HID/high-pressure lamps have a much higher level of UVA photons than low-pressure lamps. Therefore, stop using UVB percentage as a meaningful indicator of sunlamp performance because a much more useful indicator is the tanning power of the lamps.

Q: How do you estimate the “tanning power” of sunlamps?

A: Measure the lamps with both a Solartech Model 5.0 (UVA/UVB) meter and a Model 6.0 UVB meter and subtract the UVB reading from the UVA/UVB (Total UVR) reading to get the UVA level. This provides an “estimation” of the tanning power of the lamp. Therefore, a sunlamp with more UVA photons, i.e., a higher mW/cm^2 reading, has more tanning power than a lamp with fewer UVA photons, i.e., a lower mW/cm^2 reading.

Q: When should sunlamps be changed?

A: Change sunlamps at the end of their useful life, i.e., when they have degraded 30 percent to 35 percent from the reading when new (i.e., at one hour of use). The hard part is determining when they have reached this point. The best tool for measuring when lamps have reached the end of their useful life is, in our opinion, a Solartech Model 7.0 (MED/hour) meter that can be used to a) calculate the performance degradation (see table below) of the lamps, and b) estimate the Te (4.0 MED) time of the lamps/equipment.

Measurement of the canopy should be made with the meter placed at 25 cm above the bench and the meter should be placed directly against the acrylic to measure the bench. (Use a plastic ruler that has been shortened to 25 cm with Velcro® attaching the meter to the ruler.) The tanning unit should be run through a complete cycle and then read at 3 to 5 minutes into the second cycle. Keep in mind that you must “standardize” your measurements in order to eliminate testing variables.

New MED/hour reading, i.e., after they have “aged” for 1 hour.

= 12.0 MED/hour (0.2 MED/minute) (12.0 ÷ 60 = 0.2) - 25% performance degradation, i.e., the point where you should order new lamps.

= 9.0 MED/hour (0.15 MED/minute) (9.0 ÷ 60 = 0.15) - 30% performance degradation, i.e., the “recommended” point to change lamps.

= 8.4 MED/hour (0.14 MED/minute) (8.4 ÷ 60 = 0.14) - 35% performance degradation, i.e., the lowest point to change lamps.

= 7.8 MED/hour (0.13 MED/minute (7.8 ÷ 60 = 0.13) - 40% performance degradation, i.e., the point where you will get complaints.

= 7.2 MED/hour (0.12 MED/minute (7.2 ÷ 60 = 0.12) 

On several occasions we purposely allowed sunlamps to age beyond the 30-percent performance degradation level in order to get client reaction. In our experience, a few clients will ask when you plan to change your lamps when they have degraded by 35 percent; most clients will comment when they have degraded by 40 percent; and almost of them will comment when they have degraded by 50 percent. The strange thing—for which we have science technology no answer—is that several clients asked for the tanning unit where the lamps had degraded by 50 percent; and one or two clients started to complain when the lamps had degraded by only 10 percent.

Click here for full size graph

Q: How can you estimate the Te (4.0 MED) time?

A: All that is required is to divide 4.0 by the MED/ minute reading to get an “estimation” of the Te (4.0 MED) time. [Note: The “official” Te (4.0 MED) time must be determined with results obtained using a spectroradiometer.” Using the values from the calculations above, we find:

= 12.0 MED/hour (0.2 MED/minute) (4.0 ÷ 0.20 = 20.0) = 20.0 minute Te (4.0 MED) time.

= 9.0 MED/hour (0.15 MED/minute) (4.0 ÷ 0.15 =26.7) = 26.7 minute Te (4.0 MED) time.

= 8.4 MED/hour (0.14 MED/minute) (4.0 ÷ 0.14 =28.6) = 28.6 Minute Te (4.0 MED) time.

= 7.8 MED/hour (0.13 MED/minute (4.0 ÷ 0.13 =30.8) = 30.8 minute Te (4.0 MED) time.

Q: Why do you recommend the use of new-era low-pressure sunlamps?

A: The graph above compares the D-UVR (skin damaging UVR) photons and the tanning power (Td) photons for a) sunlight at noon on a typical summer day in the Midwest; b) a traditional 160-watt lamp; c) a 1,000-watt HID/high-pressure lamp; d) a first generation 160-watt new-era lamp; and e) a second generation 160-watt new-era lamp. The results should speak for themselves. As you can see, HID/high pressure and new-era low-pressure lamps (especially the second generation new-era lamps) have a much better “ratio” between the D-UVR (skin-damaging UVR) and Td (tanning dose) photons (and much more tanning power) than does either a traditional low-pressure lamp and/or sunlight. In summary, they provide more of what your clients want, i.e., tanning power and less of what they don’t want, i.e., the potential to damage their skin.

Q: What is meant by sunlamp compatibility?

A: There are two different types of compatibility—“regulatory compatibility” and “manufacturer compatibility.” Regulatory compatibility means that a replacement sunlamp must be within ± 10 percent of the original lamp that came installed in the tanning equipment. Therefore, any replacement lamp that has a “compatibility sheet” proving it meets this standard is compatible from a regulatory point of view.

Manufacturer compatibility means that the tanning equipment vendor may, and often does, state that a specific sunlamp must be used in order to maintain its product liability insurance and keep its product warranty in force.

Keep in mind that salon owners utilizing an “incompatible” sunlamp become the “manufacturer of record” and must file new certification documents with FDA and using an incompatible lamp may make “null and void” your salon liability insurance.