Learn the science behind mercury vapor lighting. This article explains the uses and benefits of mercury vapor lighting, and situations when you may want to choose it as a light source.
Mercury vapor lighting (also known as high pressure mercury vapor), often referred to as ‘lightning in a bottle’, is an effective commercial lighting option.
Mercury vapor lights use mercury and a ballast as do fluorescent lights, but the similarities end there. Instead of a near-vacuum, the mercury vapor light has a fill gas pressure close to that of surrounding air, and the gap between the electrodes is much, much smaller.
“Lightning in a Bottle”
Rather than the gentle glow of a long fluorescent tube, mercury lights are bright, compact sources. Mercury vapor lights, and their metal-halide cousins, have been described as “lightning in a bottle.” They are discharge sources like fluorescent, but the mercury vapor lights produce a blindingly bright continuous arc across the electrodes.
The higher pressure of the mercury vapor light changes the light’s output compared to the low pressures in a fluorescent bulb.
Very Visible Light
Instead of having predominantly ultraviolet light, the mercury vapor light produces predominantly visible light without the aid of phosphors. The light is very blue, but very much visible.
In some mercury vapor bulbs, an additive (a “dopant”) is mixed into the glass to block the remaining ultraviolet light.
Efficient Lighting Sources
Mercury vapor lights are very efficient, and are used in commercial landscaping, roadway overhead lighting, warehouse and factory lighting, and sports field lighting.
Like fluorescent lamps, they have a life that is measured in many thousands of hours.
Slow Warm-up Time
One noticeable characteristic of mercury vapor bulbs is a slow warm-up time. They emit only a very faint glow for the first couple of minutes, and do not reach full brightness for about ten minutes. If you quickly turn them off and back on, it takes several minutes again to regain full brightness.
Thanks to our guest lighting expert – Lance Kaczorowski, who brings a wealth of expertise to the site:
Kaczorowski, a native of New York City, now resides in Fort Wayne, IN.
Kaczorowski has a 4-year degree in Mechanical Engineering from the University of Texas at Austin, and also a 2-year degree in Electronics Engineering Te...