WHAT ARE METAL HALIDE LIGHT BULBS?

A metal-halide lamp is an electric light that produces light by an electric arc through a gaseous mixture of vaporized mercury and metal halides[1][2] (compounds of metals with bromine or iodine). It is a type of high-intensity discharge (HID) gas discharge lamp.[1] Developed in the 1960s, they are similar to mercury vapor lamps,[1] but contain additional metal halide compounds in the arc tube, which improve the efficiency and color rendition of the light.

Metal-halide lamps have high luminous efficacy of around 75 - 100 lumens per watt,[2] about twice the efficiency of mercury vapor lights and 3 to 5 times that of incandescent lights,[1] moderately long bulb life (6,000 to 15,000 hours)[2][3] and produce an intense white light. As one of the most efficient sources of high CRI white light, metal halides are the fastest growing segment of the lighting industry.[1] They are used for wide area overhead lighting[2] of commercial, industrial, and public spaces, such as parking lots, sports arenas, factories, and retail stores,[1] as well as residential security lighting and automotive headlamps (xenon headlights).

The lamps consist of a small fused quartz or ceramic arc tube which contains the gases and the arc, enclosed inside a larger glass bulb which has a coating to filter out the ultraviolet light produced.[1][3] Like other HID lamps, they operate under high pressure (4 to 20 atmospheres)[1] and require special fixtures to operate safely, as well as an electrical ballast. They also require a warm-up period of several minutes to reach full light output,[2] so they are not typically used for residential room lighting, which is turned off and on frequently.

Power Output	ANSI Codes
20W	M175
39W	M130
50W	M110
70W	M98, M139, M143
100W	M90, M140
150W	M102, M142
175W	M57, M137
200W	M136
250W	M58, M138, M153
320W	M132, M154
350W	M131, M171
400W	M59, M135, M155
450W	M144
750W	M149
1000W	M47, M141

What are Metal Halide Light Bulbs? Questions and Answers