- Institutional and commercial buildings often have fluorescent lamps.Michael Hitoshi/Digital Vision/Getty Images
A fluorescent lamp is a gas discharge lamp that produces visible light by using electricity to excite mercury vapor. Fluorescent lamps are common in institutional and commercial buildings. Smaller, more compact sizes of fluorescent lamps are becoming popular in homes due to the fact that fluorescent lamps convert electricity into useful light in a more efficient manner than incandescent lamps. Although this leads to lower energy costs, fluorescent lamps have a number of drawbacks or hazards.
- Some ballasts include a sensor.fluorescent lamp image by Valentin Mosichev from Fotolia.com
Fluorescent lamps use a ballast to stabilize the current within the lamp and to provide the initial voltage required to start the arc discharge. A fluorescent ballast can fail if the wrong size lamp is used or a burned-out lamp is left in the fixture. Incorrect wiring or incorrect line voltage also can cause failure. Some ballasts stop functioning if they fail, but others continue to function, which leads to overheating. When a fluorescent lamp shuts itself off only to turn back on, the fault might be due to a failing ballast. Some ballasts are integrated with a sensor that shuts off the ballast when when it gets too hot and turns back on after it cools. The problem is that any number of faults, such as a power surge or component failure, can cause this safety precaution to fail. Another hazard of overheating ballasts is leakage. Magnetic ballasts are usually embedded in tar to reduce emitted noise. This tar may melt and leak from the ballast when it starts to overheat.
- Long fluorescent lamps may have starting voltages up to 950 VAC.Fluorescent overhead lamp in office image by Alexey Kuznetsov from Fotolia.com
Fluorescent fixtures that are longer than 24 inches and those used in areas of high humidity, such as outdoors, should have an electrical ground in order to operate properly and to prevent electric shocks. This is because fixtures with longer lamps typically operate at higher voltages than their shorter counterparts. Some long fluorescent lamps have high starting voltages, as much as 950 volts alternating current (VAC), representing a real threat of a shock hazard if inadvertent contact is made with electrical connectors. In order to prevent this, the lamps should be properly seated in their sockets and proper grounding fixtures used.
Breakage and Mercury Hazards
- Mercury is in all fluorescent lamps.fluorescent bulb image by Albert Lozano from Fotolia.com
Some fluorescent lamps can cause shrapnel injuries when they break due to pressure inside the lamp. When this happens, the phosphor from the glass might get into the wound and prevent blood clotting. A small amount of mercury is in all fluorescent lamps. The mercury is in a liquid form when the lamp is cold, but it turns into a gaseous form when the lamp becomes heated. Mercury vapor is a highly toxic substance, as is liquid mercury. Mercury can cause major respiratory tract damage, kidney damage, brain damage and central nervous system damage. Even though the mercury inside fluorescent lamps is in a small amount, it is still considered toxic and must be disposed of carefully.