Lighting-Gallery.net
Lamps => Modern => Topic started by: RadiantMV on March 17, 2022, 06:01:31 PM
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Is it true that ceramic metal halide lamps have a higher UV output than a standard metal halide? And if so is it usually UVA?
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I’m curious to know this as well. I wonder how one could make a shield as a precaution if necessary.
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I know some of the lower wattage CMH lamps intended for indoor use usually have a UV block doping applied on the outer envelope. It's usually marketed as fade block or similar on the lamp packaging or literature. Anyway the open rated CMH lamps should have acceptable max UV output so maybe use those. As for the enclosed rated ones, use of a proper enclosure should also help to block UV output.
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Like quartz, the ceramic arctube is transparent to UVC, so the amount of UV from CMH lamps are the same as QMH lamps.
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For practical purpose the amount and composition of the emited UV is mainly dictated by the standards governing the intended use.
Technically it is thematter of the outer bulb properties, but these are always designed according to what the related standards mandate. So the UV emission of a CMH designed for shop indoor use is way lower even when the outer material is quartz than e.g. a MV intended for street lighting even when the outer is ahard glass.
Thething is the basic hard glass lets pass way larger portion of the UV than a quartz intentionally doped the way to not pass virtually any.
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The first CMH lamps were unprotected and had very high UV-A flux plus a considerable portion of UV-B and UV-C. During around 1995-1998 all manufacturers changed over to UV-Block quartz for the compact lamps and PAR types. However the large lamps with ellipsoidal and tubular bulbs still transmit most of the UV-A and UV-B.