All About Mercury Vapor Lamps
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What is a Mercury Vapor Lamp?

History of the Mercury Vapor Lamp
The history of the mercury vapor lamp goes all the way back to 1835, when an English inventor and scientist by the name of Charles Wheatstone first started experimenting with what would happen when an arc of electricity was passed through mercury vapor. His experiments resulted in different colors being emitted depending when a prism was introduced into the mix. Then a few years later in 1860 another Englishman -- John Thomas Way -- developed a very primitive version of the mercury vapor lamp. Later in 1892 Leo Arons of the University of Berlin also came up with an early version of the lamp. However, Arons lamp emitted light that had too much of a bluish-green tinge. It wasn't until 1901 that a version of the mercury vapor lamp we know of today is an invention of American electrical engineer Peter Cooper Hewitt. On September 17, 1901, Hewitt received a US patent for his invention. Then two years later, Hewitt developed an upgraded version of his mercury vapor lamp that offered better light color quality. One drawback of Hewitt's original mercury vapor lamp was the large amount of mercury that the lamp needs. In the 1930s, researchers worked to see if they could still use the same process, just with less mercury required. These newer lamps were ultimately made by companies such as General Electric.Mercury Vapor Lamp Pros
Energy Efficiency -- When compared to incandescents -- and even some fluorescent options -- mercury vapor lamps use less energy and have greater luminous efficacies.
Bright White Light -- Mercury vapor lamps are highly regarded for their ability to produce a very clean white light, especially when compared to earlier lighting options.
Long Lamp Life -- Generally speaking, mercury vapor lamps will last for at least 24,000 hours, with many lasting even longer. This makes them a great option for hard-to-get fixtures, such as in factories, sports arenas, and streetlights.
Mercury Vapor Lamp Cons
Phasing Out -- Probably the largest con to mercury vapor lamps is that the United States government is phasing them out as a lighting option. In fact, the passing of the Energy Policy Act of 2005 banned mercury vapor ballasts in the US. And the European Union is reportedly working to begin banning mercury vapor lamps as of 2015.
Blue-Green Light -- Due to the materials used to produce light in a mercury vapor lamp, the light it emits can sometimes have a very blue-green tinge to it. This has ultimately made these type of lamps a less desirable option for retail applications and other indoor uses. They can cause human skin color to look strange.
Warm Up -- Mercury vapor lamps require a lengthy warm up time. This can be anywhere from four to seven minutes.
Mercury Issues -- Like with other lighting options, the fact that mercury vapor lamps contain mercury has caused quite a concern for users. Because of this, disposal in not easy. The US Environmental Protection Agency (EPA) has specific rules on how burned-out mercury vapor lamps should be thrown away.
UV Radiation -- Another cause for concern is the fact that mercury vapor lamps emit UV radiation. Although the outer bulb helps to keep much of the radiation away from the end user, if the outer bulb was to break and the inner arc tube kept emitting light, the amount of UV radiation could potentially cause serious health risks for those exposed to it.
Retrofitting Mercury Vapor Lamps
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Shop retrofit kits for your mercury vapor light
Mercury Vapor Lamp vs. Fluorescent/CFL
As we have already mentioned, mercury vapor lamps offer a lot of great advantages -- vivid light and long lamp life -- which has given them the nickname of "the workhorse" of lighting, making them great choices for places that need reliable lighting such as streetlights and sports arenas. When compared to fluorescents and CFLs, these newer technologies do have major drawbacks when it comes to surrounding ambient temperature as they have a hard time operating in very cold areas, making them potentially not as great an option as mercury vapor lamps for outdoor applications. On the flip side, fluorescents and CFLs do have certain characteristics that help make up for some of the disadvantages with mercury vapor lamps. For instance, fluorescents take much less time to heat up and emit light. Plus they offer even longer lamp life and greater energy efficiency. It's important to note that switching to a fluorescent lighting solution does not do away with mercury. They still contain a small amount, and as such have their own disposal rules and regulations.Mercury Vapor Lamp vs. LEDs
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Shop LED Replacements for Mercury Vapor