LED WATCH The Standards Wave BY JAMES BRODRICK Rolls On At <strong>the</strong> movies, we get so caught up in <strong>the</strong> on-screen action that we seldom think about all <strong>the</strong> months <strong>of</strong> behind-<strong>the</strong>-scenes work that made our two hours <strong>of</strong> cinematic enjoyment possible—much less about <strong>the</strong> army <strong>of</strong> people who patiently and painstakingly carried out that work. Not just <strong>the</strong> producer, director and screenwriter, but also those unsung heroes—from <strong>the</strong> art director, to <strong>the</strong> set designer to <strong>the</strong> gaffer—who played far less glamorous roles. So it is with a technology like solid-state lighting (SSL). Most people focus only on <strong>the</strong> “wow factor” <strong>of</strong> <strong>the</strong> end product, without considering all <strong>the</strong> little things that lie behind it. One <strong>of</strong> <strong>the</strong> most important <strong>of</strong> those “little things” is standards, which play a huge role in <strong>the</strong> development <strong>of</strong> any technology. Without standards and test methods to consistently characterize product performance and assure safety, an “anything-goes” mentality could create widespread confusion and make things difficult for manufacturers, consumers and specifiers alike. And that’s just what happened in <strong>the</strong> early years <strong>of</strong> SSL, which were likened more than once to <strong>the</strong> Wild West. But recent progress in standards development has brought a semblance <strong>of</strong> law and order to Dodge City, thanks to <strong>the</strong> coordinated efforts <strong>of</strong> such organizations as <strong>the</strong> IES, NEMA, American National Standards Lighting Group (ANSLG), American National Standards Institute, National Institute <strong>of</strong> Standards and Technology (NIST), Underwriters Laboratories, International Electrotechnical Commission, International Commission on Illumination (CIE) and Canadian Standards Association. These groups have helped develop standards that have already addressed many key aspects <strong>of</strong> SSL—from nomenclature, to chromaticity and performance specifications, to power supply and safety. Two <strong>of</strong> <strong>the</strong> most important <strong>of</strong> <strong>the</strong>se standards have come from IES: LM-79 specifies a standard test method for measuring <strong>the</strong> photometric and electrical properties <strong>of</strong> SSL devices in order to compare light output and calculate luminaire efficacy, while LM-80 lays out procedures for measuring lumen degradation over time, a key component <strong>of</strong> reliability and lifetime. Both are up for <strong>the</strong>ir regularly scheduled two-year reviews, with committees already formed and well-armed with lists <strong>of</strong> newly surfaced issues that may need to be addressed by updates that enable <strong>the</strong> standards to keep pace with a rapidly evolving technology. TWO ON THE WAY Two related standards from NEMA, which have been in development, are nearing publication. SSL-1, “Electronic Drivers for LED Devices, Arrays, or Systems,” is in <strong>the</strong> balloting stage and is expected to be published by <strong>the</strong> end <strong>of</strong> <strong>the</strong> year. A logical sequel to LM-79, which looks at lamp performance, SSL-1 focuses on <strong>the</strong> driver, which many feel is <strong>the</strong> weakest link in <strong>the</strong> SSL luminaire chain. The idea is to create some standards around drivers so that <strong>the</strong>y live up to <strong>the</strong> same lifetime claims as <strong>the</strong> LEDs. What good are LEDs that last for 50,000-plus hours, if <strong>the</strong>y depend on a driver that lasts only 30,000 hours About as good as <strong>the</strong> proverbial cow that yields <strong>the</strong> sweetest milk in town but has an unfortunate habit <strong>of</strong> kicking <strong>the</strong> pail over. SSL-6, “Solid State Lighting for Incandescent Replacement- Dimming,” looks at ano<strong>the</strong>r issue that’s been getting quite a bit <strong>of</strong> attention lately, namely, controllability. Many people assume that all LEDs are easily dimmable, but in fact that only holds true if <strong>the</strong> LED has an electronic driver with dimming capability and <strong>the</strong> driver is compatible with <strong>the</strong> chosen dimming control. SSL-6 provides interface recommendations for dimming control <strong>of</strong> integrated LED lamps intended to replace general service incandescent products. Like SSL-1, SSL-6 is in <strong>the</strong> balloting stage and should be published by year’s end, after which NEMA plans to initiate additional dimming standards. Both standards—SSL-1 and SSL-6—have been long-awaited and are sure to make a big difference when <strong>the</strong>y’re published, because <strong>the</strong>y’ll be filling what amounts to a huge void. THE QUESTION OF LIFETIME Still ano<strong>the</strong>r much-anticipated solid-state lighting document, which 22 www.ies.org
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