They are plasma devices, like a neon sign, and will pass as much current as the external circuit will provide, even to the point of self-destruction.
High-pressure bulbs are 3 to 5 inches long and typically powered by a ballast with 250 to 2,000 watts.
The most common is the 400 watt variety that is used as an added face tanner in the traditional tanning bed.
The goal with high-pressure tanning bulbs is to produce a high amount of UVA only.
During installation, even a small amount of oil from fingertips can cause the quartz envelope to fail in operation.
The plasma of excited mercury atoms inside the lamp emits ultraviolet light directly.
Some of the short-wave ultraviolet excites the phosphors, which then emits photons in the proper spectrum for tanning.
This includes magnetic, pure solid state, and high frequency ballasts.
This allows the ballast to energize the lamp with more than raw power, and instead operates using a combination of electrical force and induction.
High-pressure lamps range from 300 to 1,000 hours, and should be replaced when they have reached their maximum life to prevent any possible damage to the ballast,[4] although this is very rare.
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.
[5] There are no accepted published numbers for rating the overall power for lamps, except the TE (time exposure), which is almost as useless for making comparisons.
The UVB to UVA ratio percentage is considered a technologically outdated form of measuring a lamp's overall UV output and Wolff "Metric" now lists actual UVA, UVB and total UV flux powers.
The amount of UV that is generated from a low-pressure lamp is highly dependent on the temperature in the tanning unit.
As a rule, tanning lamps produce the highest amount of ultraviolet light when this temperature is between 90 and 110 °F (32 and 43 °C).
Cooling systems for tanning equipment are usually designed to maintain a range of temperature instead of providing maximum airflow for this reason.
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.
[10] Proper disposal or recycling will prevent the mercury content of the lamps from entering the environment.