Metal Halide Lamps

SECTION 2: Hazards identification

Ultraviolet (UV) Radiation The quartz arc tube, when operating, generates a considerable amount of ultraviolet radiation. The UV is filtered to acceptable levels by the glass outer envelope during normal use. However, if the outer envelope is broken, the UV filtering is lost. Lamps having ordering codes beginning with the letters “MVR” or “MXR” have the following warning notice required under Federal Regulation 21 CFR 1040.30: “WARNING: This lamp can cause serious skin burn and eye inflammation from shortwave ultraviolet radiation if outer envelope of the lamp is broken or punctured, and the arc tube continues to operate. Do not use where people will remain for more than a few minutes unless adequate shielding or other safety precautions are used. Current has commercially available SAF-T- GARD Multi-Vapor lamps that will automatically extinguish when the outer envelope is broken.” The self-extinguishing metal halide lamps referred to above have order codes beginning with the letters “MVT”. If the outer glass envelope of a SAF-T-GARD lamp is broken, although the arc tube will have self-extinguished, its support structure will still be electrically connected and could present an electrical shock hazard. Therefore, regardless of the type, if the outer envelope of the lamp is broken, turn the power off before replacing the lamps. Section 3. Lamp Composition and Detailed Ingredient Information Glass These lamps consist of an inner quartz arc tube enclosed in an outer envelope of heat-resistant glass. Depending on the lamp type, the envelope is either clear or coated with one of two different materials. The “MVR” and “MVT” lamps are coated with a phosphor material while the “MXR” lamps are coated with a diffusing material. Phosphor The phosphor used on the outer envelope of the coated lamps consists of yttrium vanadate phosphate. The material used as a diffuser in the “MXR” lamps is specially prepared kaolin clay that contains no crystalline silica or asbestos as impurities. Arc Tube The quartz arc tube contains a small amount of mercury, ranging from less than 5 milligrams in low wattage lamps up to 165 mg in a 1500-watt lamp. The arc tube contains a small amount of inert gas argon used as a fill gas. It also contains a small amount of other materials, used as an emission mix on the electrodes, but there would be no significant exposure from lamp breakage. Also, contained in the arc tube are small amounts of sodium and scandium iodide, and in some cases thorium iodide. Metals Internally, the support wires used in the lamp construction are made from nickel-coated iron or stainless steel while the electrodes are tungsten. Many of the metal halide types will use a brass base and some have high melting point lead-soldered connections to that base.