An LED Lamp Should Last … How Long?

Like smoking and carousing, unwholesome practices can reduce one’s lifespan.

University of Melbourne student Clement Wong, in a 2012 Economics Student Society of Australia newsletter article titled “Planned Obsolescence: The Light Bulb Conspiracy,” noted that Philips Lighting (Somerset, NJ; Amsterdam) had recently released an LED light bulb with an advertised life span of 20 years – the Philips 10W, 20-year LED lightbulb.
The company said the bulb was a positive response to the 2007 Energy Independence and Security Act that simultaneously banned 100W incandescent bulbs and provided a timetable for eliminating incandescent bulbs altogether. The law required the phasing out of general service incandescent light bulbs in favor of such lower-wattage, energy-saving bulbs as compact fluorescent (CFL) and Edison-style LED bulbs.
Clement also noted an earlier lightbulb lifespan change by highlighting the 1924 Phoebus Cartel, a now-obsolete conglomeration of lightbulb manufacturers that, he said, pressured all lightbulb makers to replace their long-life bulbs with ones that lasted only 1,000 hours, which more than doubled the replacement cycle and thereby increased the makers’ revenues. Clement said, “Light bulbs were deliberately made more fragile, and competitors were closely monitored (and, if necessary, fined) to ensure strict adherence to product degradation.” He said the Phoebus Cartel eventually dissolved (due to increased external competition and the disruptions of World War II), but it had successfully demonstrated that stifling innovation and product quality was a means of sustaining consistent consumption and profits.
Markus Krajewski, in a September 2014 “IEEE Spectrum” website article, “The Great Lightbulb Conspiracy,” described the Phoebus Cartel’s action: “The cartel’s grip on the lightbulb market lasted only into the 1930’s. Its far more enduring legacy was to engineer a shorter lifespan for the incandescent lightbulb.” By early 1925, Krajewski said, the lightbulb was methodized to last 1,000 hours, which was a conspicuous reduction from the previous lifespan of 1,500 to 2,000 hours. Interestingly, he described the Phoebus Cartel not as a quirky anecdote, but as a “cautionary tale about the strange and unexpected pitfalls that can arise when a new technology vanquishes an old one.”
Measuring LED life
In its 2011 paper, “LED Luminaire Lifetime Recommendations, the Next Generation,” the Lighting Industry Alliance, in conjunction with the US Dept. of Energy, deliberated LEDs’ lifespan and said the lifetime of a well-designed and manufactured luminaire isn’t determined by LED lumen depreciation, meaning, like any product, outside forces can also affect longevity. It said, “Good LEDs can be incorporated into poorly engineered products and turn the Methuselah of lighting into the exponent of ‘live fast, die young.’”
The paper reflected that assorted lumen maintenance values exist, that component reliability and analysis systems vary and that warranties may be misstated. The writers said they had modified their end-of-life demarcation to when there’s no longer enough “useful” light and again added that an LED’s useful lifespan may be affected by the luminaire or such salient products as drivers, optics and other components. Of course, “enough” useful light is subject to interpretation, but the general rule is a 30% decline in light output, which can occur in the LED itself, but is also influenced by such maintenance factors as lamp lumen and luminaire dirt depreciation, as well as such equipment factors as ambient temperature effects, heat extraction, voltage effects, driver and lamp factors, and component depreciation. The Alliance also said a well-built LED package or array should not fail entirely for a very long time.
Additionally, the report said that conventional [lamp] technologies the “rated average lamp life” is the point at which half the [tested] lamps cease to emit light, but that all sources lose light output (i.e., the light depreciates) during the rated lamp life as defined by complete “lights-out” failure of 50% of the studied lamp population. In essence, there are two dimensions in lamp lifespan considerations – total lamp failure and light depreciation.
After-installation LED failure
ST columnist Marcus Thielen, in his December 2016 column (p. 26), cautioned readers on corrosion effects in LED signs, advising signmakers who work in humid regions to avoid the use of stainless-steel screws or rivets in galvanized iron, brass screws in aluminum, or a combination of pig iron and aluminum or stainless-steel screws in mild steel. In addition, Thielen said anodized aluminum generates a thin layer of electricity that isolates aluminum oxide on the surface and prevents humidity from attacking the underlying metal. He also cautioned that penetrating the aluminum oxide layer may require unique treatments.
Thielen noted that LED circuits, even though they operate on low-voltage DC currents, influence the electrochemical potential (EP) of some fabrication materials, so if the electrical circuits, contacts or wires are exposed to moisture, including high humidity, the DC current increases the ion movement strength and thus the potential for corrosion. See this phenomenon as directly relating to the above study of outside forces affecting longevity. He said that outdoor LED signs fare better when signmakers conform to the above and following precautions:
• Create large drain holes (they’re less inclined to become obstructed);
• Ensure that stranded, DC volt wires are watertight lengthwise;
• Pot or waterproof-coat printed circuit boards and connections; • Waterproof interior sign box or channel letter connector blocks (no wire nuts); and
• Do not use exposed conductors to provide DC voltage.
Ask first
Jeff Fassett, president of Aries Graphics (Ventura, CA), the maker of Neon Wizard and LED Wizard software, is also a wizard on LED usage and software. In a recent conversation, I asked what he would advise signmakers regarding their use of LEDs. Without hesitation, Fassett said, “To do their own testing, because the tests will validate any manufacturer’s claims on brightness, beam angle, color temperature, lumens and other important aspects.” Like ST columnist Nisa Khan, Fassett notes that few consistent standards exist for LEDs, thus your own shop’s testing is one way to know the product. “You won’t really understand what you’ve got until you test it yourself,” Fassett said. He also said signmakers should inquire with their supplier as to where their LEDs are built, what materials are used and how the manufacturer – or the seller – tests them.
Fassett said LED suppliers are experiencing an expanding and more assertive market, so LED prices have become more competitive, supplier choices have increased and industry consolidations are shaking out weaker players. Fassett also advised that signshop work orders and costing files contain a summary of the LED components and any unusual or new fabrication methods, as well as the LED layout file, as a reference for any future work changes, warranty work or repairs. If possible, the work order should record the number of LED modules and their density (modules per sq. ft.), plus power supply details and other relevant notes. Such information, if created and kept in-house, allows a signshop to independently evaluate their LED-based sign projects both when delivered and when maintenance is due, in order to make intelligent decisions on future LED jobs.
Khan, in her June column (p. 32) said LED illumination isn’t intuitive, but that many lamp buyers believe LED illumination corresponds to traditional incandescent and fluorescent lamps. She also said the lighting industry’s currently specified parameters aren’t sufficient to comprehensively describe illumination and that the worldwide absence of illumination standards presents challenges for both manufacturers and users when comparing values for an appropriate set of characteristics from different lamps. Her observation relates to Fassett’s caution for signmakers to test the LEDs and any relative luminaires themselves, to know and understand the outcomes.
How to brighten a natatorium Jeff Gatzow, Optec LED Lighting’s (Ontario, CA) vice president, tells of the Waukesha South High School natatorium and how its now-replaced metal halide lighting was so dim that parents and visitors – and lifeguards – complained that they couldn’t see the swimmers. Tom Cherone, the Waukesha, WI school district’s master electrician, said the Waukesha natatorium’s original design called for indirect lighting, to lessen water surface glare, but over time the metal-halide lamp output had diminished and the chamber became more like a dungeon. He said indoor pools’ warm and humid environments are rough on lighting systems, and he worried about lamp replacement operations. If the school maintenance crew dropped and broke a metal-halide lamp in the pool, 480,000 gallons of water would need to be drained, and the pool flushed, to remove any glass.
The school district, in collaboration with an area contactor, retro-fitted the 75 x 90-ft. natatorium in a one-for-one lamp replacement; i.e., they replaced 42 1,000W metal halide fixtures with 42 of Optec’s 240W LED, high-bay luminaires, and replaced eight 36W fluorescent tubes with eight Optec 80W high-bay luminaires. Cherone, the district administrators, plus the principal, coaches, teachers, students, parents, visitors – and lifeguards – are happy with the new, bright LED lighting. He said the new system reduced the room’s lighting energy costs by 70% when compared to the metal halide system. He also expects energy savings in lamp warm-up times (metal halide requires 15 minutes, LED are instant on) and he said the school district now plans to replace all its pool lighting with LEDs. The district is also studying a changeover in the school parking lot lighting.
Cool panel lights
No offense, but most LED panel lights are just that, panel lights, but sometimes a job requires something cool – a panel light from the dashboard of a ’36 Cord roadster, for example, or a P-51 Mustang instrument board. San Diego-based Visual Communication Co. (VCC), a firm that specializes in innovative LED, incandescent, neon and specialty indicator lights and light pipes, has introduced its L65 Series, a 5mm LED, front panel snap-in light that features a 30° or 45° viewing angle and an advanced reflector system to maximize brightness, even in daylight situations. In addition to its attractiveness, the shock- and impact-resistant L65 Series lamps – available as 2-24VDC – are water- and oil-resistant when installed with an O-ring gasket accessory.

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