from www.lightnowblog.com
Results of the latest round of CALiPER testing were released recently, and as usual they can tell us a thing or two about the current state of solid-state lighting. As you may know, DOE’s CALiPER program supports testing of a wide array of SSL products available for general illumination, and publishes the results in summary and detailed reports, as well as a searchable database that allows side-by-side comparisons with previous rounds and benchmark products. CALiPER Round 13 focused on three types of LED luminaires for commercial and industrial applications: high-bay luminaires, wallpacks, and 2′x2′ troffers.
One thing it shows is that even in commercial lighting applications, which require high levels of light output and carefully designed light distribution, SSL luminaires are now clearly able to compete on a level playing field with traditional products. Most of the indicators from CALiPER Round 13 shed a positive light on the LED products in these categories, underscoring the fact that obtaining photometric data, understanding how it relates to the needs of the application in question, and comparing SSL and conventional options carefully are key to choosing the right products.
Round 13 shows that the average luminaire efficacy of products continues to increase, and color quality continues to improve. The average luminaire efficacy of the LED products tested in Round 13 was more than 60 lm/W, and most of them met or exceeded the efficacy of the traditional benchmark products tested. And while there were still some LED products that didn’t perform well, particularly with regard to light distribution, there was significantly less variation in product performance than in previous rounds, and a majority were found to meet or exceed manufacturer performance claims. Many of the products tested are taking advantage of the inherent strengths of SSL to achieve uniform light distribution similar to that of conventional luminaires, and in some cases are even improving on the uniformity of distribution.
Of special interest in Round 13 were the 2′x2′ troffers. These were all integral luminaires, with SSL technology designed into the product as a whole in order to take full advantage of it – quite a different animal indeed from the LED products that are designed to simply replace the 4′ linear fluorescent lamps used in 2′x4′ troffers. While those LED linear replacement lamps still fall short of their fluorescent counterparts in terms of light output and distribution, the LED 2′x2′ troffers tested in Round 13 fared much better, with some of them meeting the specifications developed by the DOE Commercial Building Energy Alliances and the DesignLights Consortium, a collaborative of utility and regional energy efficiency organizations.
Despite improvements, Round 13 shows that accurate reporting and product literature are still concerns – not only for LED lighting products, but also for their benchmark counterparts. In all cases, but especially for luminaires, it’s important to know which version of a product the photometric data applies to, and not to assume that other versions of the product perform similarly. The products that were found to have accurate manufacturer claims – which were in the majority – tended to include detailed photometric performance specifications that referenced LM-79 and avoided the use of equivalency statements. Products that omitted this detailed photometric data and made vague equivalency claims tended to fall short of expectations. What’s more, although only a portion of the products carried equivalency claims, most of those claims were found to be misleading or false, which means that buyers and specifiers should examine and understand photometric performance of both the LED products and conventional luminaires that they may be replacing, rather than rely on equivalency statements in product literature. A new DOE Technology Fact Sheet, “Establishing LED Equivalency,” offers guidance on understanding SSL equivalency claims.
Friday, December 16, 2011
Monday, December 5, 2011
Trust, but verify: Reducing Risk Prior to LED Implementation
Copied from: http://www.creeledrevolution.com/blog/2011/12/05/trust-but-verify-reducing-risk-prior-to-led-implementation/
Those old enough to remember the 1980s may recall then President Ronald Reagan’s, “Trust, but verify” messaging as part of the United State’s Cold War negotiations with the former Soviet Union. While evaluating LED luminaires may not seem as important as dealing with a nuclear arms race, the same “Trust, but verify” philosophy should be used to reduce risk prior to any large scale implementation of LED products.
But what should you verify? To better limit risk it’s important to understand where risk resides. Some typical questions could include:
• How do I know I’ll get the necessary sustained light levels over the duration of my application?
• How do I know that the luminaire mounting is strong enough to withstand vibration over time?
• How do I know the luminaire and its paint finish are durable enough to resist corrosion?
It’s important to understand the difference between specifying product features versus specifying product performance. Specific product features may imply performance, but by themselves fall short of ensuring any specific level of performance. For example, a street light luminaire that advertises a product feature utilizing four mounting bolts, instead of two, may imply a certain level of increased performance. For instance, it may imply resistance to conditions such as vibration. But without credible performance data that specifically addresses vibration resistance, no assumption regarding a product’s resistance to vibration should be made. Specifying product performance removes product features from the specification and puts the focus on what actually reduces risk, some level of product performance.
Lets get back to the questions. Would the level of risk be more greatly reduced by pointing to either product specific features or credible performance data? Well if the movie Jerry Maguire was about a great lighting designer, he would have probably shouted, “Show Me the Data!” There are relevant standards in place that can be referenced to quantify levels of durability for the three questions above and more. Once the necessary performance level is determined and specified, potential suppliers should verify their ability to provide certain levels of performance with credible data so as to reduce risk.
But, what about product warranties – they minimize risk, right? Although warranties are designed to reduce risk, warranties also present certain risks as well. The first risk is based on the strength and credibility of the company offering the warranty in the first place. Two nearly identical five-year warranties may seem equal at first glance, but if there is a high degree of uncertainty that one of the two companies may even survive for five years, it’s unlikely these two warranties would be viewed as equals. Overall product reliability is another factor to consider when determining the potential strength or value of a warranty. Companies with proven performance are probably less likely to experience catastrophic failures on a scale that may jeopardize their ability to honor warranty claims compared to new companies entering the market.
So the goal to managing risk shouldn’t be left solely to a good warranty. Even the best warranties do not eliminate risk, since associated costs may be incurred should warranty claims need to be made. Therefore, specifying performance during the product selection process is the best way to minimize risk. Remember, “Trust, but verify.”
Those old enough to remember the 1980s may recall then President Ronald Reagan’s, “Trust, but verify” messaging as part of the United State’s Cold War negotiations with the former Soviet Union. While evaluating LED luminaires may not seem as important as dealing with a nuclear arms race, the same “Trust, but verify” philosophy should be used to reduce risk prior to any large scale implementation of LED products.
But what should you verify? To better limit risk it’s important to understand where risk resides. Some typical questions could include:
• How do I know I’ll get the necessary sustained light levels over the duration of my application?
• How do I know that the luminaire mounting is strong enough to withstand vibration over time?
• How do I know the luminaire and its paint finish are durable enough to resist corrosion?
It’s important to understand the difference between specifying product features versus specifying product performance. Specific product features may imply performance, but by themselves fall short of ensuring any specific level of performance. For example, a street light luminaire that advertises a product feature utilizing four mounting bolts, instead of two, may imply a certain level of increased performance. For instance, it may imply resistance to conditions such as vibration. But without credible performance data that specifically addresses vibration resistance, no assumption regarding a product’s resistance to vibration should be made. Specifying product performance removes product features from the specification and puts the focus on what actually reduces risk, some level of product performance.
Lets get back to the questions. Would the level of risk be more greatly reduced by pointing to either product specific features or credible performance data? Well if the movie Jerry Maguire was about a great lighting designer, he would have probably shouted, “Show Me the Data!” There are relevant standards in place that can be referenced to quantify levels of durability for the three questions above and more. Once the necessary performance level is determined and specified, potential suppliers should verify their ability to provide certain levels of performance with credible data so as to reduce risk.
But, what about product warranties – they minimize risk, right? Although warranties are designed to reduce risk, warranties also present certain risks as well. The first risk is based on the strength and credibility of the company offering the warranty in the first place. Two nearly identical five-year warranties may seem equal at first glance, but if there is a high degree of uncertainty that one of the two companies may even survive for five years, it’s unlikely these two warranties would be viewed as equals. Overall product reliability is another factor to consider when determining the potential strength or value of a warranty. Companies with proven performance are probably less likely to experience catastrophic failures on a scale that may jeopardize their ability to honor warranty claims compared to new companies entering the market.
So the goal to managing risk shouldn’t be left solely to a good warranty. Even the best warranties do not eliminate risk, since associated costs may be incurred should warranty claims need to be made. Therefore, specifying performance during the product selection process is the best way to minimize risk. Remember, “Trust, but verify.”
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