Metal Halide lighting systems belong to the High Intensity Discharge (HID) family of lights. Metal-Halide lamps create light by means of an electric arc between tungsten electrodes. The bulb itself is filled with a mixture of specialized gases and metal salts. The gases facilitate the initial striking of the arc, which then heats and evaporates the metal salts creating plasma. The plasma greatly intensifies the light output but operates at a very high pressure and temperature.

The color and quality of light depend on the mixture of gases and salts present inside the bulb. Due to their small form factor and relatively high light output compared to fluorescents and incandescent lights, they were adopted for a variety of uses.

While initially bright, the high pressure and heat severely limit metal-halide lamp lifetimes. Metal-halides are only rated for up to 10,000 hours. To make matters worse, metal-halides lose 40% of their initial brightness by 5,000 hours and the light output continues to steadily decline. If used indoors, the heat generated by these bulbs strains the air conditioning systems and expends further energy.

Disadvantages:

  • Short lamp life – Requires constant replacement bulbs and maintenance, driving up costs and electrical waste.1850_hibay
  • Quick lumen depreciation – Though initially bright, the light output beings to dim rapidly after installation. Can result in spotty lighting if not all lamps are replaced at the same time.
  • Ballast noise – Over the course of its lifetime, some metal-halide ballasts begin emitting a loud, annoying buzzing sound.
  • Hot running temperature – Raises ambient temperature when used indoors, placing unnecessary strain on the air-conditioning system. The heat poses a fire hazard so proper precautions must be taken. In rare cases, lamp may explode at end of lifetime.
  • Warm-up time – Metal-halide systems require 5-15 minutes of warming up time to achieve operating temperature and pressure. Starting takes longer in colder climates.
  • Re-Strike Time – When extinguished, the metal salt vapor must solidify before the lamp can be relit. This process takes 5-10 minutes. This may pose problems if there is a power outage and immediate illumination is required (tunnels).

Commonly found in:

  • Warehouses
  • Gas Stations
  • Sports Arenas
  • Gymnasiums
  • Auditoriums

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