Metal Halide Lighting

Metal Halide lighting is very commonly specified and designed for lighting in indoor and outdoor athletic facilities. This is because they produce a high light output for their size, making them a compact yet powerful light source.

Metal halide lamping produce light by passing an electric arc through a high-pressure mixture of argon, mercury, and a variety of metal halides. The heat generated by the arc then vaporizes the mercury and metal halides, which produce light as the temperature and pressure reaches full capacity.

Since metal halide lamps operate under high pressure and temperature, they require special fixtures, known as "ballasts", to provide proper starting and operating voltages and regulate the current flow in the lamp. About 24% of the energy used by metal halide lamps produces light which makes them more efficient than fluorescent lamps, and substantially more efficient than incandescent bulbs. This is yet another reason why they are so common in sports settings.

With the introduction of specialized metal halide mixtures in recent years, metal halide lamps are now available with color temperature as low as 3000K (very yellow) to 20,000K (very blue). This can be useful to the architect or owner for the appearance of the lighting source.

The biggest drawback to metal halide lighting is the startup. A “cold” (below operating temperature) metal halide lamp cannot immediately begin producing its full light capacity because the temperature and pressure in the inner arc chamber require time to reach full operating levels. Starting the initial argon arc sometimes takes a few seconds, and the warm up period can be as long as five minutes (depending on lamp type). During this time the lamp exhibits different colors as the various metal halides vaporize in the arc chamber.

If power is interrupted, even briefly, the lamp’s arc will extinguish, and the high pressure that exists in the hot arc tube will prevent re-striking the arc. This is a major life-safety concern as it could create manufacturing shut down or a safety issue. A few metal halide lamps are made with quartz capabilities where the lamp, ballast and socket are built to withstand the 30,000 volt re-ignition pulse supplied via a separate anode wire. But these tend to be costly and are only used as a last resort.

At the end of a metal halide lamp’s life, they exhibit a phenomenon usually known as “cycling”. As the lamp gets older, it requires a higher voltage. Once this required voltage exceeds the supplied voltage, the arc fails and the lamp goes out.

Below are samples of the most commonly used Metal Halide lamps:

Metal Halide Lamp 1