Product Monday: Linear Lighting System by JESCO

JESCO-DL-FLEX-HD - with backgroundJESCO’s DL-FLEX-HD and DL-FLEX-CTA are architectural-grade, low-wattage, dimmable, flexible linear LED lighting systems. DL-FLEX-HD offers “high LED density” comprised of 66 LEDs/410 lumens per foot with uniform, tight beam patterns eliminating typical light “dots.” DL-FLEX-CTA provides users the ability to select specific white color temperatures, from 2400K to 7000K, using a radio frequency remote or a DMX controller.

Compact, lightweight, these linear lighting units are well suited for providing inconspicuous, low-scale, low-energy task, accent and display lighting for a multitude of wide-ranging interior commercial, institutional and high-end residential applications.

DL-FLEX-HD is available by the foot or in 16-foot pre-wired rolls with two input power connectors. There are 66 LEDs per foot, 1056 per 16-ft. roll. DL-FLEX-HD is field cuttable every 1 1/16″ and compatible with JESCO’s Smart Track adjustable shelf power system. JESCO’s proprietary, onboard, Constant Current IC chips control each individual LED, providing uniform intensity and lumen output over the entire run, as well as temperature control.

DL-FLEX-CTA is available in 4- or 12-inch lengths and easily plugs together for longer runs up to 20 feet, and is field cuttable every 4-inches. It can be controlled by a simple CTA radio frequency, wall mounted or hand-held remote controller or a DMX controller for more complex requirements.

Hi-bond 3M double-sided, adhesive tape allow DL-FLEX-HD and DL-FLEX-CTA to be quickly mounted and installed to most surfaces. Light strips mount end to end for bendable or angled patterns, or continuous rows.

Click here to learn more.

LUX on Top 10 Trends in Workplace Lighting

LUX recently posted an article identifying the top 10 trends transforming workplace lighting:

1. Retrofits
2. Controls
3. From T5 to LED
4. The end of the louver
5. New working patterns
6. Personal control
7. Wellbeing and productivity
8. Monitoring
9. Li-Fi
10. Internet of Things

Retrofit, controls, LED, different shielding (due to LED luminaires), yes. These are among the major trends impacting lighting. Personal control, focus on wellbeing and productivity, I’d like to see more of that to call them major trends. Monitoring is part of a new interest in data, and hope to see it become a larger trend. Li-Fi is in development, we’ll see how it impacts general lighting. The Internet of Things is going to be big, but we’re not sure what it’s going to look like yet. We’re at the start of it.

Your thoughts?

Check out the article here.

Evaluating LED Luminaire Reliability

A brief article I wrote for tED Magazine. Reprinted with permission.

While LED promises long service life as one of its primary advantages, accurately projecting lifetime remains a challenge. The Next Generation Industry Alliance’s (NGIL) LED System Reliability Consortium (LSRC) recently updated a key report, LED Luminaire Lifetime: Recommendations for Testing and Reporting, to shed some light on the issues involved.

The lighting industry is predominantly using lumen depreciation to express expected life of LED products. A published life of 50,000 hours at L70, for example, means average light output for a population of products is expected to decline by 30 percent after 50,000 hours of operation. The lumen depreciation may be for any reason—general lumen depreciation among functional LEDs, depreciation within the luminaire, or a percentage of LEDs failing outright.

The industry uses the LM-80 standard to test lumen depreciation for LED packages, modules and arrays up to 10,000 hours. TM-21 provides a procedure for extrapolating this information to L70 or some other target value. Because luminaire design affects light output, LM-80 testing data provides a baseline for estimating lumen depreciation for LED products under certain conditions. As such, luminaire design may affect lumen depreciation, as could stress factors such as heat and humidity experienced in the field. Lifetime claims for LED luminaires and lamps are made by manufacturers based on their own methods and data, as there is currently no industry standard for doing this.

While lumen depreciation in the light source is popularly used as an indicator of product lifetime, LED products are really systems featuring other components that may fail first. This challenges earlier assumptions centered around the light source being the leading point of failure. In fact, research conducted by RTI International—which resulted in the 2013 report, Hammer Testing Findings for Solid-State Lighting Luminaires—suggests that other luminaire components are far more likely to fail before the LEDs do. This has several big ramifications.

First and foremost is that LM-80 and TM-21 get us to a future lumen depreciation value, not necessarily service life. As such, it’s one indicator of life.

In its updated recommendations, LSRC also added color shift as a consideration in defining service life for applications where color quality is important. This is an issue of color stability over time in a given product and color consistency between products installed in the same space over time. Because predicting color stability is difficult and there is no industry standard for it, for color-critical applications, designers should ask manufacturers about how they ensure color stability and negotiate an appropriate warranty, if needed.

Different projects have different needs, and the definition of service life for an LED product may change based on the project. For a given project where color quality is critical, for example, service life might be defined by as when average light output has declined by X percent (due to lumen depreciation or LEDs failing) or when color has shifted beyond a specified limit of Y, with X and Y being defined by the designer and/or the owner based on the application. If the LEDs are visible with occupants having a direct view, the point at which a certain percentage of LEDs fail (go dark) could be another failure mode, one based on aesthetic considerations.

Because of the close dependency of such parameters and demand for products, LSRC recommends the industry delineate LED products into three reliability categories—lamp-replacement grade, standard grade and specification grade. Each category would be defined within a range of parameters, from light output to color quality. This would help manufacturers minimize costs by designing products for specific markets rather than a one-size-fits-all approach.

LSRC advises LED product buyers to focus on qualifying suppliers. Determine how manufacturers support their reliability and service life claims, and ask them to back up these claims by revealing their methods and data. As industry-consensus robustness tests develop, buyers should require their suppliers to follow them.

Next, understand the product warranty, what it covers and what it doesn’t, and whether the warranty period covers a reasonable fraction of claimed life. Ask if the manufacturer will maintain a stock of replacement products and components and for how long.

LED is still young, and it’s still evolving not only in terms of technology, but how we evaluate and rate performance. As the LED revolution continues to develop, buyers should protect themselves by qualifying suppliers and asking the right questions, and qualifying products by evaluating the application need and associated parameters for defining useful life.


Recently read an interesting article about LED lighting in ELECTRICAL CONTRACTOR. Early on, a quote from Kevin Willmorth:

“LEDs bring a global rethink,” said Kevin Willmorth, owner of Lumenique LLC, a lighting product development and consultant firm in Germantown, Wis. “They introduce us to a new era of lighting as an appliance. But this new era will also be more complex when specifying and installing. Upfront homework will go a long way in making better, more informed choices for your clients.”

It’s an interesting read, catch it here.

Another Novel Lighting Technology: Nanowires

nanoBizLED recently published an interesting story about a solid-state lighting technology that could become efficient enough to take on the LED: nanowires.

I’ve theorized that given LED’s efficiency and performance, it may well be the last major light source for the foreseeable future. There will continue to be a great deal of innovation for many years, but all within the realm of LEDs, control and connectivity. There will be competitive technologies like OLED and plasma, but these may be limited to specific applications whereas LEDs have already become ubiquitous.

That being said, I could be wrong. New approaches may improve the efficiency of lighting or otherwise improve its performance such that another revolution may be in our future. What are your thoughts?

Check out the article here.

Product Monday: Lumark Night Falcon Floodlight by Eaton

The Lumark Night Falcon LED Floodlight Luminaire by Eaton is designed to replace up to 400W metal halide products in general area, building façade, wall wash and large sign lighting applications in commercial and industrial exterior environments.

The luminaire is available in two lumen packages including nominal 9,400 lumens (85W) to replace 250W metal halide products, and nominal 14,600 lumens (129W) to replace 400W metal halide luminaires.

The floodlight’s optics are engineered to provide superior uniformity and illumination to the targeted application. Maximum luminaire spacing is achieved utilizing a wide 6H x 6V NEMA distribution, reducing the number of luminaires required and installation costs in select applications. The luminaire is offered in standard 4000K correlated color temperature with 3000K and 5700K available.

The Night Falcon product features a compact, robust designed incorporating a separate driver housing and thermal fins for maximum heat dissipation resulting in longer luminaire and LED life. The heavy-duty, die-cast housing is IP66 and 3G vibration rated for exceptional durability and long term reliability. The luminaire’s lumen maintenance is greater than 90 percent at 50,000 hours for years of maintenance-free service.

For pole-mounted applications, an optional integrated sensor allows the luminaire to be dimmed to 50% lumen output when no activity is detected, providing additional energy savings by reducing light levels and power consumption. This option complies with the new provisions of California Title 24. In addition, an optional National Electrical Manufacturers Association 7-pin photocontrol receptacle enables wireless dimming when used with compatible photocontrol.

Click here to learn more.


Great Primer on LED Lighting

Magnitude Lighting Converters sent us a link to a page on their website that includes a terrific and lengthy infographic describing how LED lighting works, concluding with detail about the difference between constant current and constant voltage operation.

Check it out here.


HID Lamp Indexes Decline During First Quarter 2015

NEMA’s shipment indexes for high intensity discharge (HID) lamps continued to decline at the start of 2015.

Sodium vapor lamp shipments fell 11.5% on a seasonally adjusted basis compared to the same period last year. Shipments of mercury vapor lamps retreated by 18.4% year-over-year (y/y). Although the index for metal halide lamps registered a modest year-over-year increase of 1.2%, shipments were still below the level during calendar year 2014.

Sodium vapor lamps gave back 2.4 percentage points, decreasing to a share of 30.1%, while mercury vapor lamps declined marginally to 3.5%. The market share of metal halide lamps increased to a new high level in the series, at 66.5% for the quarter.


NEMA Issues Position Paper on LED Flicker

Yesterday, LightNOW published a guest blog post by Jim Brodrick, DOE’s SSL Program Manager, on a new IEEE recommended practice on LED flicker.

As metrics, IEEE uses % flicker, operating frequency and flicker index. A graphic is provided that plots % flicker relative to the light source’s operating frequency. Color shading reveals safe and low-risk regions. Equations enable calculation of maximum flicker for a given light source at various operating frequencies.

The National Electrical Manufacturers Association’s Lighting Systems Division subsequently published its own position paper, Temporal Light Artifacts (Flicker and Stroboscopic Effects).

NEMA takes the position that the IEEE recommended practice proposes limits that appear to eliminate any chance of health or distraction effects, but that the limits may be overly strict, which could add unnecessary cost to driver electronics. Even incandescent lamps do not fall within the no- or low-risk region.

In the paper, NEMA asserts that standardization around flicker is hampered by lack of adequate metrics, and calls for new metrics. Current metrics, the paper states, do not quantify flicker correctly because they don’t fully account for the effects of both the frequency and wave shape of the light stimulus. The human eye is sensitive to both wave shape and frequency effects, and a metric or specification that doesn’t allow for them will be too strict for some cases and too lax for others.

Get the position paper free here.

NEMA is currently working to produce a new flicker and stroboscopic effect measurement standard and will define application-dependent recommendations.

Brodrick on New Recommended Practice for LED Flicker

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

by Jim Brodrick, SSL Program Manager, U.S. Department of Energy

The emergence of high-frequency electronic ballasts for use with fluorescent lighting did away with most general-illumination flicker concerns back in the 1990s. That is, until the advent of LEDs, which have put flicker back on the table. To help address it, the Institute of Electrical and Electronics Engineers (IEEE) has just published the first recommended practice on the topic, IEEE Std 1789-2015. Entitled “Recommended Practice for Modulating Current in High-Brightness LEDs for Mitigating Health Risks to Viewers,” it explains what’s known about flicker in LED lighting and provides guidance that can help manufacturers design drivers or select them for their products, to minimize possible flicker-associated health and productivity effects.

Flicker is the variation in illuminance or luminance over a period of time. All AC-powered light sources flicker, typically in a periodic manner. However, flicker can be more pronounced in LEDs because, unlike other sources, LEDs have no persistence. This means that LEDs respond to change in forward current with a near-instantaneous change in light output. This is even true for phosphor-coated LEDs, as common LED phosphors respond much faster than some of their fluorescent brethren.

But LEDs pose no inherent flicker hazard, and there are LED lighting products on the market that exhibit less flicker than their conventional counterparts. What primarily determines the degree of flicker in LEDs is the driver. However, it’s often more costly to make drivers that minimize flicker — and such drivers often have to be larger in size, to accommodate the components that smooth out the light emission. For that reason, LED flicker is more likely to be a problem in lower-priced products, as well as in those (such as MR16s) that have size constraints.

In addition, the use of dimmers can exacerbate or cause flicker. The key is compatibility between the dimmer and the driver, which is something that should be checked with the manufacturer of the dimmer or luminaire, by asking for the percent flicker (a figure obtained by subtracting the minimum from the maximum light output in a cycle, and dividing that by the maximum plus the minimum light output in a cycle) and the PWM frequency (for luminaires dimmed using pulse-width modulation) when the system is dimmed. But if the manufacturer can’t supply you with those figures, you may have to test the product yourself.

Why is flicker bad? For one thing, in addition to being annoying and distracting, it can cause eyestrain, blurred vision, and impairment of performance on sight-related tasks. And in those who are flicker-sensitive, it can cause debilitating headaches and migraines — 10% of the population is estimated to suffer from migraines, and that’s only one of the groups prone to flicker sensitivity. According to the IEEE recommended practice, flicker has been reported to contribute to autistic behaviors, and can be a trigger for epileptic seizures, although the frequencies seen in architectural products are generally above the critical range for epilepsy. Some of these problems might occur even when the flicker isn’t detectable by the eye. Periodic flicker can be characterized by its amplitude modulation, its average value over a periodic cycle, its shape, and its periodic frequency. And all of these characteristics affect the viewer’s biological response.

IEEE Std 1789 makes recommendations for managing the biological effects of flicker within two defined risk levels. While operating outside these levels does not mean there will be biological effects, operating within them limits the risk of creating biological effects to defined levels. Determination of which level is appropriate depends on many factors, including characteristics of the user population, exposure time, types of tasks undertaken in the lighted space, and one’s risk sensitivity. Tradeoffs with product cost, size, and performance are associated with the various recommendations:

To prevent seizures at frequencies below 90Hz, keep the percent flicker below 5% (light doesn’t trigger seizures at frequencies above 70Hz).

To limit the other biological effects of flicker (so that the risk of creating other biological effects is low), use the following formulas to determine the maximum percent flicker:

At frequencies below 90Hz, maximum percent flicker = frequency x 0.025 [E.g., at 80Hz, the maximum percent flicker is 80 x 0.025 = 2%]
At frequencies between 90Hz and 1250Hz, maximum percent flicker = frequency x 0.08 [E.g., at 250Hz, the maximum percent flicker is 250 x 0.08 = 20%]
At frequencies above 1250Hz, no restrictions on the percent flicker. (Note: this is the minimum allowed frequency for basic PWM.)

To prevent the other biological effects of flicker (so that there’s no risk of creating other biological effects), use the following formulas to determine the maximum percent flicker:

At frequencies below 90Hz, maximum percent flicker = frequency x 0.01 [E.g., at 50Hz, the maximum percent flicker is 50 x 0.01 = 0.5%]
At frequencies between 90Hz and 3000Hz, maximum percent flicker = frequency x 0.0333 [E.g., at 1200Hz, the maximum percent flicker is 1200 x 0.0333 = 40%]
At frequencies above 3000Hz, no restrictions on the percent flicker. (Note: this is the minimum allowed frequency for basic PWM.)

This important new recommended practice provides specifiers with flicker performance requirements for managing the risk of biological effects, thereby enabling specifiers to better determine project requirements, and encourages manufacturers to test for flicker and report the results on their cut sheets. That way, the flicker issue can be laid to rest for SSL, just as it was for fluorescent lighting 20 years ago.