Month: February 2014

Brodrick on LED Product Lifetime and Reliability

Republication of Postings from the U.S. Department of Energy (DOE) Solid-State Lighting Program by Jim Brodrick, U.S. Department of Energy Next to energy efficiency, long life is probably the most…

Republication of Postings from the U.S. Department of Energy (DOE) Solid-State Lighting Program

by Jim Brodrick, U.S. Department of Energy

Next to energy efficiency, long life is probably the most publicized of solid-state lighting’s (SSL) potential advantages, and plays a key role in any cost-benefit analysis. But understanding how LED lighting products fail, and communicating it effectively, aren’t easy matters — and are further complicated by the cost and impracticality of traditional life testing. The problem is laid out in a U.S. Department of Energy (DOE) SSL Technology Fact Sheet, Lifetime and Reliability, which summarizes what’s known about the topic, including typical causes of failure for LED lighting products, the difference between lifetime and reliability, and currently available methods for measuring and reporting a product’s lifetime.

Many folks are collaborating to better understand the issue of SSL lifetime — including an industry working group known as the LED Systems Reliability Consortium (LSRC), which is meeting this week at DOE’s 11th annual SSL R&D Workshop, in Tampa, FL. A spinoff of an earlier DOE working group that developed the report LED Luminaire Lifetime: Recommendations for Testing and Reporting, the LSRC recently completed a new study utilizing a highly accelerated life-test method — called the “hammer test” — intended to produce failures in SSL luminaires in a reasonable test period, with the goal of providing insight into potential failure modes. Entitled Hammer Testing Findings for Solid-State Lighting Luminaires, the new report was prepared for the LSRC by RTI International and is just the first step in the LSRC’s ongoing work on this important topic, which is helping to forge a common understanding and may influence future standards.

All lighting products eventually reach the end of their useful life. For conventional, lamp-based lighting systems, this most often occurs when the lamp burns out, which is why lifetime focus has traditionally been confined to the lamp itself. But LED lighting isn’t only lamp-based, and performance is affected by a host of system components, the failure of any of which — not just the LEDs, but also the electronics, thermal manage­ment, optics, wires, connectors, and seals — can lead to failure of the entire product. In addition to catastrophic failure (i.e., total burnout), there’s also the type of failure that can occur when the light produced is unacceptable in quantity (lumen maintenance) or quality, due to degradation or shift in luminous flux, luminous intensity distribution, color temperature, color rendering, or efficacy.

Among the components that can cause failure in an LED lighting system, most of the attention has focused on the LED packages, which rarely fail catastrophically. Of the various other failure causes, lumen depreciation has received the most attention and is often used as a proxy for LED lamp or luminaire lifetime ratings, even though — for the reasons just stated — it’s not an accurate proxy. The most widely used criterion for lumen maintenance failure is when a product reaches “L70” — that is, when its light output has dropped to 70 percent of what it was when the product was new. Because failures among a set of installed products don’t all occur at once, lumen maintenance ratings are usually based on the time at which 50 percent of a sampling of products have reached L70 — a point denoted as “L70-B50.”

But depending on the application, L70 may be too much — or too little — lumen depreciation. And there are other ways to convey lumen maintenance performance, such as identifying the expected lumen maintenance at a fixed time interval (e.g., 25,000 hours) — which may allow for more-effective comparisons between products, especially when the calculated L70 value exceeds the intended product-use cycle or the anticipated lifetime of another system component.

In the recent hammer test, commercial indoor SSL luminaires were subjected to extreme environmental stressors, including temperature cycling, temperature and humidity soak, and high-temperature bake, with power cycled to provide electrical stress as well. All of the luminaires survived more than 100 cycles of temperature shock (-50º C to 125º C), and nearly half survived more than 300 cycles. The failures that were observed typically occurred in the driver circuit, with board-level failures being most common. The 611 LEDs in these luminaires endured nearly 1 million LED-hours of cumulative exposure to the hammer test, with only four failures — two of which were attributed to solder-joint fatigue, and the other two to board-level corrosion.

The findings reinforce the belief that LEDs in lighting systems are highly reliable, even under extreme conditions, and indicate that other luminaire components are more likely to fail first. While the results suggest that SSL luminaires will have a low probability of random failure in the field during normal use, additional work is needed to determine actual wear-out mechanisms, quantify failure modes, and determine acceleration factors, in order to provide estimates of lifetime and reliability in normal operation.

Users may eventually be able to determine the best balance between lifetime, reliability, serviceability, warranty, sustainability, and cost for the lighting application in question. Typically, long life comes at a cost, but its advantages may not be realized if the expected use cycle is less than the lifetime. For example, a building scheduled to be renovated in the next 15 years may not benefit from lighting products with a 30-year lifetime. Instead, it may be better to use a less-expensive product that has a shorter useful life but higher reliability. On the other hand, shorter-lived products generate more waste and compromise sustainability goals.

As the technology matures, the dependence of LED package performance on other components will continue to require that discussions about lifetime be focused at the luminaire level, as lamp performance in different luminaires can vary. Innovative luminaire designs and control strategies — such as variable drive products that maintain lumen output — will further complicate lifetime measurement and reporting. As with many other performance attributes, LEDs have the potential to surpass conventional lighting for longevity — as shown by the negligible changes observed in lumen maintenance and color in the L Prize®-winning product after 25,000 hours of testing. But choosing the right product requires some understanding of expected failure mechanisms, lifetime, reliability, and serviceability, as well as asking the right application-specific questions.

1 Comment on Brodrick on LED Product Lifetime and Reliability

Lighting Controls Association Updates Energy Codes Course

The Lighting Controls Association (LCA) has updated EE203: Lighting & Commercial Energy Codes, a course in its popular Education Express program. Residing at the Association’s website, Education Express provides in-depth…

The Lighting Controls Association (LCA) has updated EE203: Lighting & Commercial Energy Codes, a course in its popular Education Express program. Residing at the Association’s website, Education Express provides in-depth education about lighting controls and controllable ballast technology, application, system design and commissioning.

Commercial building energy codes regulate the designed energy efficiency of nonresidential buildings. Current codes and standards require a broad range of lighting controls to ensure general lighting is turned OFF or reduced when it is not needed. In the United States, a majority of energy codes are based on the 90.1 energy standard, published by ASHRAE and the Illuminating Engineering Society, and the International Energy Conservation Code (IECC), published by the International Code Council.

EE203: Lighting & Commercial Energy Codes, which I authored for LCA as its acting education director, provides general introductory knowledge about the lighting control requirements imposed by the 2010 version of ASHRAE/IES 90.1 and the 2012 version of the IECC (as initially published, without addenda). Process maps outlining each step towards compliance provides a graphical learning experience and enables students to easily visualize the process.

lca

At the conclusion of the course, an optional online comprehension test is available, with automatic grading; a passing grade enables the student to claim education credit. EE203: Lighting & Commercial Energy Codes is accredited/registered with the American Institute of Architects (AIA) Continuing Education System (CES), which recognizes 2.5 Learning Units (LU)/Health, Safety, Welfare (HSW) credits; and the National Council on Quality in the Lighting Professions (NCQLP), which recognizes 2.5 LEUs towards maintenance of Lighting Certified (LC) certification.

Founded in 2006, Education Express serves nearly 20,000 students, who have benefited from more than 140,000 completions of learning modules and nearly 90,000 comprehension tests taken online, enabling them to earn education credit.

For more information about Lighting Controls Association’s Education Express, including a complete course listing, click here and then select the Education Express button.

No Comments on Lighting Controls Association Updates Energy Codes Course

Cooper LightingAnnounces 2014 Class Schedule for the SOURCE Lighting Educational Facility

Cooper Lighting recently announced the release of the 2014 SOURCE calendar of educational classes for the lighting and design community. The SOURCE, located at Cooper’s Peachtree City, GA office, offers…

SOURCE_2014_Calendar

Cooper Lighting recently announced the release of the 2014 SOURCE calendar of educational classes for the lighting and design community. The SOURCE, located at Cooper’s Peachtree City, GA office, offers a wide variety of seminars designed to broaden the understanding of lighting and its many different applications.

Most classes are offered multiple times throughout the year and include:

• Lighting Fundamentals
• LEDs, Controls, New Technologies and Retrofits for Energy-Efficient Solutions
• LED Exterior Lighting Solutions
• Healthcare Lighting Solutions
• LEDs and New Technology for Residential Lighting

Educating more than 9,000 professionals each year, classes at the SOURCE are ideal for a range of professionals and students from lighting designers, engineers and contractors, to utility personnel and facility managers. In many cases, classes offered satisfy continuing education credit requirements for professional organizations to which architects, designers and lighting professionals belong. The SOURCE supports the design industry by providing seminars and workshops that are pre-certified educational opportunities to obtain such recognition.

Click here to see the schedule.

No Comments on Cooper LightingAnnounces 2014 Class Schedule for the SOURCE Lighting Educational Facility

Cree Introduces Wireless Control System

Cree has introduced SmartCast Technology, a self-programming wireless lighting control system for its LED luminaires. Designed to be intuitive and easy to use, luminaires enabled with Cree SmartCast Technology create…

Cree has introduced SmartCast Technology, a self-programming wireless lighting control system for its LED luminaires. Designed to be intuitive and easy to use, luminaires enabled with Cree SmartCast Technology create their own secure network, learn about their environment and form groups to maximize savings, all with the push of a single button.

Cree SmartCast Technology is currently available in the company’s CR Series LED troffers, CS Series linear luminaires and KR Series downlights, as well as via a 0-10V interface for control of existing dimmable LED luminaires.

Click here to learn more.

No Comments on Cree Introduces Wireless Control System

Product Monday: LED T8 by Philips

Philips Lighting’s InstantFit LED T8 offers a “click to fit” LED retrofit alternative for linear electronic instant-start fluorescent lighting, offering up to 40% energy savings. The Philips InstantFit LED replacement…

Philips Lighting’s InstantFit LED T8 offers a “click to fit” LED retrofit alternative for linear electronic instant-start fluorescent lighting, offering up to 40% energy savings.

The Philips InstantFit LED replacement lamp requires no re-wiring as it includes a smart electronic design that is compatible with existing electronic instant-start ballasts and sockets. The result is a reduction in the time it takes to change from fluorescent to TLED lighting–to mere seconds.

The product will be available sometime this quarter. Stay tuned here.

New InstantFit LED T8 from Philips Slashes Cost and time to replace Fluorescent Tubes with LED technology

1 Comment on Product Monday: LED T8 by Philips

Lighting Controls Association Publishes Construction Forecast

My contribution to the Lighting Controls Association’s blog this month is a summary of indicators of current economic conditions in the construction industry, along with the latest AIA Consensus Construction…

My contribution to the Lighting Controls Association’s blog this month is a summary of indicators of current economic conditions in the construction industry, along with the latest AIA Consensus Construction Forecast. In short, overall nonresidential construction is projected to strongly rebound in 2014.

Read it here.

No Comments on Lighting Controls Association Publishes Construction Forecast

DOE Publishes Report on Accelerated Life Testing of SSL Luminaires

The U.S. Department of Energy (DOE) has published the findings of a new study utilizing a highly accelerated life-test method (called the “hammer test”) intended to produce failures in SSL…

The U.S. Department of Energy (DOE) has published the findings of a new study utilizing a highly accelerated life-test method (called the “hammer test”) intended to produce failures in SSL luminaires in a reasonable test period, with the goal of providing insight into potential failure modes. Entitled Hammer Testing Findings for Solid-State Lighting Luminaires, the report was prepared by RTI International for DOE’s LED Systems Reliability Consortium. In the testing described in the report, indoor SSL luminaires were subjected to extreme environmental stressors, including temperature cycling, temperature and humidity soak, and high-temperature bake, with power cycled to provide electrical stress as well.

Among the findings:

* All of the luminaires survived more than 100 cycles of temperature shock (-50ºC to 125ºC).
* Nearly half survived more than 300 cycles.
* The failures that were observed typically occurred in the driver circuit, with board-level failures being most common.
* The 611 LEDs in these luminaires endured nearly 1 million hours of cumulative exposure to the hammer test, with only four failures – two of which were attributed to solder-joint fatigue, and the other two to board-level corrosion.

The findings reinforce the belief that LEDs in lighting systems are highly reliable, even under extreme conditions, and indicate that other luminaire components are more likely to fail first. While the results suggest that SSL luminaires will have a low probability of random failure in the field during normal use, additional work is needed to determine actual wear-out mechanisms, quantify failure modes, and determine acceleration factors, in order to provide estimates of lifetime and reliability.

Click here to read the report.

No Comments on DOE Publishes Report on Accelerated Life Testing of SSL Luminaires

LED A-line Replacement Lamps Begin Making Inroads into the Market

NEMA’s index for LED A-line replacement lamps increased for the second consecutive quarter in Q3 2013. Shipments during the quarter registered a gain of 71.9 percent compared to the previous…

NEMA’s index for LED A-line replacement lamps increased for the second consecutive quarter in Q3 2013. Shipments during the quarter registered a gain of 71.9 percent compared to the previous quarter. Shipments rose 60.2 percent on a year-over-year basis. Halogen A-line lamp shipments improved as well, eclipsing the level during the same period last year by 140.7 percent. Sales of incandescent A-line lamps returned to positive territory during the quarter, following declines in the previous three quarters, advancing by 16.2 percent. However, the index declined 14.8 percent versus Q3 2012. The index for compact fluorescent lamps (CFLs) dipped on both a quarterly and annual basis, declining by 2.8 and 11.2 percent, respectively.

Despite their recent rapid gains, LED A-line lamps constitute just a tiny fraction of the market. Their share increased 20 basis points to 0.7 percent during the quarter. Shares of halogen and incandescent A-line lamps also grew, reaching 9.6 percent and 55.1 percent, respectively. Meanwhile, CFLs gave back 4.5 percentage points, falling to a share of 34.6 percent.

NEMA

No Comments on LED A-line Replacement Lamps Begin Making Inroads into the Market

Cree Unveils 200 Lumens/W LED Luminaire Prototype

Cree recently demonstrated an LED concept luminaire operating at 200 lumens/W, which is more than twice the efficiency of the best linear fluorescent luminaires. The prototype leverages Cree’s vertical integration…

Cree recently demonstrated an LED concept luminaire operating at 200 lumens/W, which is more than twice the efficiency of the best linear fluorescent luminaires.

The prototype leverages Cree’s vertical integration with innovations in LED chips, optics, materials technology and novel system design to deliver unprecedented performance.

The 3,200-lumen concept luminaire delivered greater than 200 lumens/W at 80 CRI at thermal equilibrium while remaining within the ANSI color specification for 3000K. The innovations behind the concept luminaire will enable Cree to deliver increased performance in LED luminaire applications at a lower cost to accelerate LED adoption.

No Comments on Cree Unveils 200 Lumens/W LED Luminaire Prototype

Product Monday: LED Wraparounds and Lensed Striplights by Columbia Lighting

Hubbell Lighting recently launched three new LED luminaires from Columbia Lighting—the LWC Premium Wraparound, LPT Premium Lensed Striplight and LRO Lensed Striplight, well suited for lighting kitchen or dining areas,…

Hubbell Lighting recently launched three new LED luminaires from Columbia Lighting—the LWC Premium Wraparound, LPT Premium Lensed Striplight and LRO Lensed Striplight, well suited for lighting kitchen or dining areas, work or utility spaces, hallways, restrooms, and other areas with lower ceilings.

Columbia Lighting’s LWC Premium Wraparound fixture is available in lumen packages ranging from 2,400 to 4,700 nominal lumens with an efficacy up to 96 lumens/W. The LWC is designed with an attractive acrylic prismatic lens and overlay to provide smooth LED lighting without pixelation. Combined with softly glowing ends, these features make the LWC a uniquely practical and attractive wraparound. Available in 2’ or 4’ lengths, the LWC delivers 50,000 hours of illumination at L80 and features a high-efficiency driver with options for 0-10V continuous dimming, step dimming, and fixed ON/OFF. Heavy gauge steel housing gives the luminaire rigidity. The LED light engine is accessible and replaceable for future maintenance or upgrades.

Columbia Lighting’s LPT Premium Lensed Striplight matches the LWC (LED) and WC (fluorescent) in appearance and is a suitable replacement for fluorescent luminaires. Equivalent to the LPT in performance, the company’s LRO Lensed Striplight is the design match for Columbia lighting’s LAW (LED) and AWN (fluorescent) products. Both the LPT and LRO are available in 4’ and 8’ lengths, in eight lumen packages (2,700, 5,000, 6,400, and 9,600, 5,400, 10,000, 12,800 and 19,200) with efficacy up to 106 lumens/W, and are rated for 50,000 hours at L80 lumen maintenance. A solid-state driver provides options for 0-10V continuous dimming, step dimming, and fixed ON/OFF.

All three products are available in multiple color temperatures (3500K and 4000K), can be surface mounted or suspended, provide high color rendering (82 CRI), are offered with an optional 1,400-lumen battery pack factory installed, and come standard with a five-year warranty.

Click here to learn more.

Columbia Lighting LRO-1

Columbia Lighting LWC-1

3 Comments on Product Monday: LED Wraparounds and Lensed Striplights by Columbia Lighting

Type on the field below and hit Enter/Return to search