Linear Fluorescent Frequently Asked Questions
What is the difference between Color Temperature and Color Rendering?
The appearance of light is often referred to as warm, neutral and cool. Color temperature is the metric, in degrees Kelvin, that gives a quantitive value to the terms warm, neutral, cool and all variations. Color rendering (CRI) is a numerical value that indicates how well a particular light source will render colors accurately compared to natural daylight. Together color temperature and color rendering provide a lot of information about the quality of light for specific applications.
Fluorescent Energy Efficiency Guidelines
Linear Fluorescent lighting energy efficiency is dependent on the lamp/ballast system.
Typical configuration options for office / classroom applications:
- T12 system: 40W bulb + magnetic ballast = lowest efficiency (Federal regulations require phase out of T12 system by 2012)
- Standard T8 system: 32W bulb + electronic ballast = higher efficiency
- Advanced T8 system: 30W, 28W or 25W bulbs + compatible electronic ballast = highest efficiency
Retrofit Energy Savings Estimates:
- From T12 system to Standard T8 system - 25% energy savings
- From T12 system to Advanced T8 system - 43% energy savings
- From Standard T8 system to Advanced T8 system - 12% energy savings
What is the role of phosphors in Fluorescent Bulbs?
The color of light produced by a fluorescent lamp depends on a blend of rare earth phosphors used to coat the wall of the tube. A 2800K color temperature bulb produces a "warm" appearing light. A 4100K bulb produces a "cool white" light.
Specific blends of rare earth phosphors with names like Cerium, Europium and Yttrium (also used in LEDs) can produce a range of color temperatures from 2500K to 6000K. In addition, these phosphor blends allow for high color rendering (82 to 95 CRI), and improved lamp efficacy.
What are the benefits of TCLP compliant lamps?
Typical fluorescent lamps contain toxic mercury in the range of 8 to 14 milligrams. For a number of years manufacturers have offered a low-mercury version of their popular lamps. Philips "Alto," Osram "Ecologic," GE "Ecolux" - these lamps contain 3.5 to 4 milligrams of mercury. Promoted as "green," the lamps are TCLP compliant meaning they pass, according the manufacturer, the Federal standard that qualifies them as non-hazardous waste. In some states, TCLP compliant lamps do not need to be recycled, they can go directly into landfills, reducing disposal costs. Other states require recycling regardless of the mercury content in the bulbs.