Tanning lamp
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Tanning lamps (or sometimes called tanning bulbs) are the part of a tanning bed, booth or other tanning device that actually produce the ultraviolet. While there are literally hundreds of different tanning lamps, they can usually be classified in two basic groups: low pressure and high pressure. Within the industry, it is common to call high pressure units "bulbs" and low pressure units "lamps", although there are many exceptions and not everyone follows this example. This is likely due to the size of the unit, rather than the type. Both types require an oxygen free environment inside the lamp.
Virtually every tanning lamp or bulb requires a ballast to provide power. While an incandescent lamp, like a typical household light bulb uses a resistor filament to restrict the flow of power inside the lamp, tanning lamps do not. They are plasma devices, like a neon sign, and will flow as much power as you make available to them, even to the point of self destruction. [1] Thus a ballast is needed to regulate the amount of electricity that flows to them.
The primary purpose of the tanning lamp to create a suntan artificially. This is accomplished in a tanning bed, tanning booth, tanning canopy or free standing single bulb tanning unit. The quality of the tan (or how similar it is to a tan from the natural sun) depends upon the spectrum of the light that is generated from the lamps. Most tanning lamps produce much more UV than the sun on a typical day. This gives the user a faster base tan, but one that fades faster and offers less protection from the sun than a natural tan.
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[edit] High Pressure Bulbs
High pressure bulbs are 3 to 5 inches long and typically powered by a ballast with 250 to 800 watts, with some reaching higher levels. The most common is the 400 watt variety that is used as an added face tanner in the tradional tanning bed. High pressure lamps use quartz glass, and as such do not filter UVC. Because UVC can be deadly, a special filter glass (usually purple) is required that will filter out the UVC and UVB. The goal with high pressure tanning bulbs is to produce an ultra high amount of UVA only. Using a tanning bed or other device with high pressure bulbs but no filter glass is extremely dangerous and should never be done. UVC is used in germicidal lamps and for water purification [2] but damages human skin.
The contents of a high pressure lamp are inert gas (such as argon) and mercury[3]. There are no phosphors used, and the mercury is clearly visible if it is not in a gaseous state. Great care must be taken when handling the high pressure bulb (and any other quartz bulb) and you should never touch it with your fingers. Leaving even a small amount of oil from your hands will cause premature failure of the bulb, and can even cause it to break, due to the extreme heat generated at normal use, which can cause the oil deposited on the bulb to boil. Because the bulb contains mercury, great care should be used if a bulb is broken, to prevent accidentally exposing yourself to the toxic mercury. Most commercial replacement bulbs come with a special pocket wipe, usually containing alcohol, to clean the bulb in case it is accidentally touched when installing.
[edit] Low Pressure Lamps
Low pressure lamps more closely resemble the common fluorescent lamp used in offices everywhere (see image at top of page). The lamps are sized by using common codes for fluorescent lamps such as F71T12BL50BP In this example, the F71 denotes the length, nominally 71 inches. The T12 section refers to the width of the lamp in 1/8th increments, making a T12 lamp 1.5 inches in diameter. The other numbers are optional, but commonly used, with the BL standing for a blue phosphor when the lamp is active, the 50 indicating a 5% UVB (95% UVA) rating, and the BP indicating bi-pin ends, which all F71 lamps have. Lamps with RDC, or Recessed Dual Connector lamp ends may have the code RDC on them, and are typically found in F73 and more rarely F72 and F74 sizes. The RDC connector is actually a plastic piece that fits over the two bi-pins and allows the lamps to be installed in telescopic lamp ends. These are less common as the lamp end parts are significantly more expensive for the tanning bed manufacturer to use.
Like all fluorescent lamps, low pressure tanning lamps work when the ballast directs enough energy to the lamp that a plasma is generated inside the lamp. The lamps are coated on the inside with special phosphors and contain a small amount of mercury (20ml typical). Unlike high pressure lamps, the glass that is used in low pressure lamps automatically filters out all UVC. Once the plasma is fully flowing (less than one second), the plasma literally strips away the outer electrons from the mercury, sending them into the phosphor, which produces photons in the proper spectrum for tanning. The electrons, now in a lower energy state, will jump back into place onto the first mercury atom they find with an electron missing.
[edit] Ballasts
In the older style (but still most popular) "choke ballast", each end of the lamp has its own cathode and anode, however, once the lamp has started, the plasma flows from one end of the lamp to the other, with each end acting as a single cathode or anode. The starter is a plasma switch itself, and temporarily connects the cathode on one end of the lamp to the anode on the other end of the lamp, causing the lamp ends to heat up quickly, or "preheat". Many F71 lamps are still called "pre-heat bi-pin" for this reason.
Newer electronic systems work differently and always treat one end of the lamp as a cathode and one end as an anode. whereas the choke style always works at 230VAC at 60hz (220-230VAC/50hz in Europe [4]), newer electronics work very differently. This includes magnetic, pure solid state, and high frequency ballasts. These new ballasts operate at voltages up to 600VAC, and at 20,000hz, with some high frequency ballasts operating as high as 100,000hz or higher. This allows the ballast to energize the lamp with more than raw power, and instead operates using a combination of electrical force and induction. This allows a 100 watt lamp to fully light with as little as 65 watts.
The obvious advantage of the newer electronics is that they use less electricity, cost less to operate, and operate at temperatures that are well below choke ballasts. Choke ballasts can case serious burns if they have been in operating for a while. Some new electronic ballasts get as little as 10F hotter than ambient temperature, even after running for an extended period. The obvious disadvantage of the newer electronics is price. It can cost 3 to 5 times more per lamp to use electronic ballasts than traditional choke ballasts, which is why choke ballasts are still used in the majority of new tanning systems.
Another disadvantage of the older style choke ballast is they are designed for European electricity, and require incoming voltage in the range of 220VAC and 230VAC. Most US homes have 240V service and businesses use 208V / three phase service that requires these beds to use a buckboost transformer in order to receive the proper voltage. Too low a voltage will result in the lamp starter not letting the lamp ignite (or at the least, very slowly) whereas too high a voltage can lead to premature failure in the starters and lamps. Average cost of these transformers is $200 to $250. While this makes the newer electronics cost about the same for the typical tanning bed, buckboost transformers are usually sold seperately, so the total cost is not always obvious to the consumer at first glance.
[edit] Low Pressure Lamp Sizes and Wattages
Tanning lamps come in several configurations which are considered standards within the industry,including:
- F59 and F60 - 80 watt lamps (shorter lamps to go in front of face tanning "buckets")
- F71, F72, F73, F74 - Typically 100W, although some F74 are 120W.
- F71 - 160W versions of the F71 for use in more expensive salon equipment, but a special ballast is required.
- F59 - 140W versions, shorter versions of the above lamp
- F79, 2M - 200W (2 metre) used only in very expensive tanning booths and beds.
The power listing for lamps is not absolute, as you can power a lamp with less wattage than listed if you use certain solid state ballasts. You can also use a 160W lamp with a 100W ballast, although there are no advantages to this. Using a 100W lamp with a 160W ballast, however, can lead to quick failure as the cathode/anode of some 100W lamps can not take the extra power. The lamps will operate at any hertz level (50hz to 120,000hz or higher). Only the ballasts and other electrical systems on the tanning bed are sensitive to hertz rating.
[edit] Lamp Life
Like all fluorescent lamps, the low pressure lamps will burn for a long period of time, however, they will loose their ability to produce a reasonable amount of UV after a short while. Typical lifespans for low pressure lamps are from 600 to 1600 hours of actual use although they may actual burn and produce very little UV for as much as 5000 hours. High pressure lamps range from 400 to 800 hours, and should be replaced when they have reached their maximum life to prevent any possible damage to the ballast [5], although this is very rare. Lamp manufacturers generally rate the "life" of the lamp to be the period of time that the lamp will continue to emit at least 70% to 80% of the initial UV, depending on the manufacturer
[edit] Lamp Types
In addition to standard lamps, there are also lamps with reflectors built inside. This is accomplished by taking the raw glass before any phosphor is used and pouring a white, opaque, highly reflective chemical on the inside of the lamp. This is done only on a certain percentage of the lamp, such as 210 degrees or 180 degrees, so that the remaining lamp is NOT coated. After this coating has dried or has been treated to insure it will stick to the surface of the glass (using heat, for example) the lamp is coated on the inside with the phospor blend as usual. Anywhere from 3 to 5 different chemicals are typically used in a blend, with the actual preportions and chemicals closely guarded as trade secrets.
The 100W version of a reflector lamp is typically called a RUVA (Reflector UVA) or less commonly HO-R (in tanning, HO means 100 watts). The 160 watt version are called VHO-R (Very High Output - Reflector). Although many people use the name VHR® to describe 160W reflector lamps, that is actually a registered trademark of Cosmedico, Ltd. and can only be legally used when describing their products.
[edit] UV Output Rating
This is one of the most confusing aspects of tanning lamps in the US, as lamps are not rated for their total output, but rather their ratio of UVA to UVB. Most people would be led to believe that a 6.5% lamp is stronger than a 5% lamp, while both lamps might have the same total UV output (or the 5% could even be stronger across the spectrum). As such, the rating on lamps only tells you the relative amount of UV, making a 5% lamp really a lamp whose UV spectrum is 5% UVB and 95% UVA.[6] There is no accepted published numbers for rating the overall power for lamps, excepting the TE (time exposure), which is almost as useless for making comparisons.
The TE isn't generally published (although usually available from the lamp manufacture if you ask), and because the US FDA biases tests against UVB, this number still can cause a weaker lamp to appear to be a stronger lamp simply because it has more UVB. Adding to this further is the fact that tanning lamps are not rated with minute exposures, only tanning beds are. This does make some sense since using the same number of the same lamp in two very different tanning bed models will give you very different results, which could vary by several minutes of maximum exposure. With this in mind, there are no magic numbers to actually compare the total output of UV between any two low pressure lamps.
[edit] Lamp Maintenance and Replacement
Tanning lamps are maintenance free, but must be kept clean as the UV can easily be blocked by dust drawn in from the cooling system, or from improperly cleaned acrylics (the clear shield that covers the lamps in a tanning bed). Most manufacturers recommend wiping the lamps and other internals clean every 200 to 300 hours of operation. Most salons will replace their tanning lamps once per year, while home tanning bed owners can expect 3 to 5 years of use. This depends solely on the number of hours the lamps have been used and the rated life of the lamp, which varies from model to model.
High pressure lamps must be handled very carefully, as any oil from the skin that is left on the bulb can cause the bulb to overheat and lead to early failure. The filter glass must also be handled carefully as it is extremely fragile by its nature. These should only be cleaned with special chemicals designed for this purpose. Operating any tanning equipment that uses high pressure bulbs without the special filter glass is extremely dangerous, and illegal in a salon, due to the high amount of UVC generated in the bulbs.
The amount of UV that is generated from a low pressure lamp is highly dependent on the ambient temperature in the tanning unit. As a rule, tanning lamps produce the highest amount of ultraviolet when this temperature is between 90 and 110 degrees Fahrenheit (32 to 43 degrees Celsius). As the temperature moves away from this range, the amount of UV produces is reduced. Cooling systems for tanning equipment are usually designed to maintain a range of temperature instead of providing maximum airflow for this reason. Higher temperatures will also reduce the expected life of the tanning lamp. This is why it is important to perform regular maintenance including checking cooling fans and insuring that vent holes are not blocked. The owners manual for the tanning equipment is the best source for maintenance schedules and methods.
[edit] Other Uses
In addition to their use in tanning beds and booths, tanning lamps (or other UV producing lamps) are used for the treatment of psoriasis, eczema, and to cure or age wood used to build violins, guitars and other musicial instruments. Water purification and medical instrument sterilization are both done using UVC, which low pressure tanning lamps do not emit and high pressure lamps are filtered to remove because of the danger of exposure to UVC.
[edit] Mercury Hazards
All fluorescent lamps contain mercury and at this time, no suitable replacement has been found. Many US states have banned disposal of lamps containing mercury[7] and have established regulations requiring that lamps that contain mercury are identified as such, however, this has caused problems for manufacturers as lamps are not produced locally, and often not in the US. As such, there have been several efforts to universally label all lamps that contain mercury with a universally accepted symbol, Hg. [8] Old lamps should be handled as you would any hazardous material in your locality and persons should take special precautions when dealing with brokens lamps to avoid contact with the mercury. This is particularly true for pregnant women. [9] These laws and guidelines are not unique to tanning lamps, and would apply to all fluorescent lamps, other lamps that contain mercury, as well as other products that contain mercury with the exception of pharmaceuticals.[10]
[edit] Footnotes
- ^ The Fluorescent Lamp: A plasma you can use.
- ^ Light Sources product description
- ^ Identifying Lamps That Contain Mercury
- ^ Electrical Power In Europe
- ^ When High Pressure Lamps Begin to Fail
- ^ Wolff System FAQ, page 24
- ^ State Regulations for Lamp Recycling for the North East US
- ^ NEMA program to label all lamps with Mercury
- ^ March of Dimes, Mercury and Pregnancy.
- ^ NEWMOA Mercury-Added Labeling Guidelines
[edit] See also
[edit] External links
- Title 12 CFR 1040.20 US FDA regulations that cover tanning lamps and devices
- UV index and UV dose
- List of Lamp and Ballast Recycling Vendors
