What is a Germicidal Bulb?

In an effort to fight bacteria and germs, developers created ultraviolet (UV) lamps featuring a germicidal bulb. These bulbs emit a low-wattage UV light to sanitize everything from medical equipment to water and food. This unique use of light comes in low-pressure and medium-pressure bulbs, depending on the job. These bulbs are a big help for many industries, but they do pose several health hazards for the humans using them.

A germicidal bulb does not look much different from traditional fluorescent bulbs used for lighting. They are not the long, white overhead bulbs found in buildings but are more like the small desktop lamp fluorescent bulbs found in many offices. These bulbs operate on very little energy, often requiring less than five watts per bulb.

A low-pressure germicidal bulb is created from quartz, not glass, and produces a kind of light that is much different from that of its fluorescent cousin. The coiled metallic wire inside the bulb, known as its mercury arc, allows ultraviolet light to pass out unmodified. When functioning, the bulb emits very little visible light.

The low-pressure ultraviolet sanitizer produced by a germicidal bulb primarily is used for ridding hospital surgical tools of harmful microbes. They also are used by the food industry during food preparation to ensure that items are germ-free. Geologists also utilize low-pressure bulbs when looking for certain minerals, because they often have a fluorescent glow under UV lighting.

A medium-pressure germicidal bulb is less common than the low-pressure bulb. One reason that it is not used as frequently is because of its higher concentration of power. Its stronger beam of UV light also looks different, producing a slightly bluish glow.

The primary use of medium-pressure ultraviolet lamps is in water purification. During industrial water sanitation processes, such as the kind used in a water treatment facility, the water passes under these intense bulbs to strip it of any impurities. This is considered a safer option than treating the water with chemicals to do the same job.

Germicidal bulbs are helpful in many ways, but humans need to be careful around them. The top concern is skin exposure to this raw UV light, because it can easily cause sunburn and, if the skin is exposed over a long time, it could cause skin cancer. Another risk is retina damage from looking into the bulb. The light can burn the cornea, causing serious damage. People handling germicidal bulbs must take many precautions to prevent these harmful effects.