Halogen Lamp Safety

Halogen lamps get hotter than regular incandescent lamps because the heat is concentrated on a smaller envelope surface, and because the surface is closer to the filament. This high temperature is essential to their operation. Because the halogen lamp operates at very high temperatures, it can pose fire and burn hazards. Some safety codes now require halogen bulbs to be protected by a grid or grille, especially for high power (1–2 kW) bulbs used in commercial theatre, or by the glass and metal housing of the fixture to prevent ignition of draperies or flammable objects in contact with the lamp. Similarly, in some areas halogen bulbs over a certain power are banned from residential use.

Additionally, it is possible to get a sunburn from excess exposure to the UV emitted by an undoped quartz halogen lamp. To reduce unintentional UV exposure, and to contain hot bulb fragments in the event of explosive bulb failure, general-purpose lamps usually have a UV-absorbing glass filter over or around the bulb. Alternatively, lamp bulbs may be doped or coated to filter out the UV radiation. When this is done correctly, a halogen lamp with UV inhibitors will produce less UV than its standard incandescent counterpart.

Handling precautions

Any surface contamination, notably fingerprints, can damage the quartz envelope when it is heated. Contaminants will create a hot spot on the bulb surface when the bulb is turned on. This extreme, localized heat causes the quartz to change from its vitreous form into a weaker, crystalline form that leaks gas. This weakening may also cause the bulb to rapidly form a bubble, thereby weakening the bulb and leading to its failure or explosion, and creating a serious safety hazard. Consequently, manufacturers recommend that quartz lamps should be handled without touching the clear quartz, either by using a clean paper towel or carefully holding the porcelain base. If the quartz is contaminated in any way, it must be thoroughly cleaned with rubbing alcohol and dried before use.

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