Fluorescent lights (also known as High Intensity Discharge, HID, or arc light) are a specific type of gas-charged luminaire that produce light through a chemical reaction that involves gases and mercury vapor interacting to produce UV light inside of a glass tube. The UV light illuminates a phosphor coating on the inside of the glass tube, emitting a white “fluorescent” light.
Using Fluorescent Lighting
In the past, fluorescent lights required a “warm up” period in-order to evaporate the gases into plasma. Several near-instantaneous starting technologies have since been developed, including “quick start,” “instant start,” and “rapid start.”
As fluorescent lights heat up, more voltage is required for them to operate. The voltage requirement is controlled by a ballast—a magnetic device that regulates voltage, current, etc.—which is necessary for a fluorescent bulb to light. As a fluorescent light ages, and becomes less and less efficient over time, it requires more and more voltage to produce the same amount of light, until the voltage eventually exceeds the capability of the ballast and the light fails.
Fluorescent Tubes vs Compact Fluorescents
The primary difference between the two is size and application. Most CFLs come in special shapes that allow them to fit in standard household light sockets. Linear fluorescent tubes also require an independent ballast that is separate from the bulb, whereas most compact fluorescent light bulbs have an integral ballast built into the base.
Both linear and compact fluorescent bulbs produce artificial light using the same technology. Compact fluorescent lights (CFLs) still use tubes but, as the name implies, are much smaller than linear fluorescent tubes. CLFs were designed to replace standard applications for incandescent bulbs, and are simply enhancements to linear fluorescent technology, by having a longer lifespan and being more efficient.
Drawbacks of Fluorescent Lighting
Fluorescent lighting has been around over 100 years and remains an inexpensive option for retrofitting old light fixtures. Fluorescents are typically a highly-efficient way to provide lighting over a large area, and are more efficient, and last longer than incandescent bulbs; however, it still has its drawbacks.
1. Fluorescent lamps contain toxic materials. The mercury, as well as the phosphorus, inside fluorescent bulbs is hazardous. If a fluorescent lamp is broken, a very small amount of toxic mercury can be released as a gas and contaminate the surrounding environment. The rest is contained in the phosphor on the glass itself, which is often considered a greater hazard than the spilled mercury.
When cleaning a fluorescent tube break, the EPA recommends airing out the location of the break and using wet paper towels to pick up the broken glass and other fine particles. Disposed glass and used towels should be placed in a sealed plastic bag. Avoid using vacuum cleaners as they can cause the particles to become airborne.
2. Frequent switching results in early failure. Fluorescent lamps age significantly if they’re installed in an area where they are frequently turned on and off. Extreme conditions can cause the lifespan of a fluorescent lamp to be much shorter than that of a cheap incandescent. Be that as it may, the life of a fluorescent lamp can be extended if left on continuously for long periods of time.
The aspect of early failure rates is something to consider if you are using fluorescent lights in conjunction with lighting controls, like motion sensors, that will activate frequently and time out.
3. Light from fluorescent bulbs in omnidirectional. Light that comes from fluorescent bulbs is omnidirectional. When a fluorescent bulb is lit, it scatters light in every direction, or 360 degrees around the bulb. This is grossly inefficient because only about 60-70% of the light given off by the lamp is being used and the rest is wasted. Certain areas tend to become overlit from the wasted light, especially in office buildings, and may require additional accessories in the light fixture itself in order to properly direct the output of the bulb.
4. Fluorescent lights emit trace amounts of ultraviolet light. In a 1993 study, researchers found that UV exposure from sitting under fluorescent lights for eight hours is equivalent to one minute of sun exposure. Health problems relating to light sensitivity may become aggravated by the artificial light in sensitive individuals.
Ultraviolet light can also affect valuable artwork like watercolors and textiles. Artwork must be protected by the use of additional glass or transparent acrylic sheets placed between the source of light and the painting.
5. Older fluorescents suffer brief warm-up period. You typically have to wait anywhere between 10-30 seconds for older fluorescents to reach their full brightness. Many newer models now utilize “rapid” start or similar technology, like that mentioned above.
6. Ballast or Buzz. Magnetic ballasts are required to operate fluorescent lights. Electromagnetic ballasts with a minor flaw can produce an audible humming or buzzing noise, however, the hum can be eliminated by using lamps with high-frequency ballasts.
7. Environmental impact and cost of recycling. As mentioned earlier, disposing of the phosphor, and more importantly, the toxic mercury in fluorescent lamps is an environmental issue. Regulations imposed by the government require special disposal of fluorescent lamps separate from general and household waste.
Most of the time, the energy savings outweigh the cost of recycling, but recycling remains an additional expense to ensure the bulbs are properly disposed of. In some cases, if the disposal of lamps is too expensive, people are no longer encouraged to recycle them.
If you have questions or would like additional information on whether fluorescent lighting is right for your business, call our office at 1-608-661-5555 to speak with Lighting Certified expert at Energy Performance Lighting.