Q: Our church is restoring two chandeliers with three rings of lamps, totaling 38 lamps. Presently, the rings are incandescent. The lamps on the top two rings are exposed so we want them to be decorative, preferably globe-shaped. We had planned on using compact fluorescent lamps, but a local lighting retailer suggested we consider cold cathode lamps. He says the CCFLs are dimmable like incandescent lamps. Our lighting consultant says the color temperature should be 3000K or 3500K for our application. What do you think? And where can we find the right lamps?
A: Using dimmable cold cathode lamps (known as CCFLs) is a good way to go. They have an average rated lamp life of 25,000 hours, as compared to CFLs at 10,000 hours. You can get them in a globe shape (known as a G-lamp), but make sure to get ones that have white glass envelopes, because they also come in a clear or frosted versions that would show the spiral tubing within.
Take a look at those made by TCP (www.tcpi.com). They offer a smaller diameter 3W G20 (8G2003WH) that gives the equivalent of 15 to 20 watts worth of illumination, or the slightly larger-diameter 5W G25 (8G2505WH) that gives 25 to 30 watts worth of illumination and the 8W G25 (8G2508WH) that gives 35 to 40 watts. If there are other companies out there making dimmable CCFLs let me know and send me samples to test. I am happy to get the word out about any company that makes a good product.
As far as color temperature goes, I would lean toward a 2700K as opposed to the cooler 3000K or 3500K, especially if there are incandescent lamps being used in other lighting fixtures in the church. The color differentiation would be noticeable, especially since CFLs and CCFLs don’t get more yellow when they are dimmed, as incandescent lamps do. But if you change out all the lamps in all the fixtures to CCFLs with a 3000K temperature then that would be good way to go as well.
Q: What does RLM stand for? Everyone knows what they are, how to specify them etc., but no one seems to know what RLM means. Help!
A: These days it means reflector luminaire manufacturer, but originally it meant reflector light microscopy. It is a fixture that is designed to project light downward, which has gained new interest in communities with Dark Sky ordinances.
