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Lamp Flicker Accelerates Standards
and Test Procedures
While all artificial lighting exhibits some flicker, it varies widely by
lamp type and model. Moreover, dimming capability, which helps to
reduce energy consumption, may increase flicker. The performance
of LED products in particular – largely as a result of the drivers’ functional-ity – has been reported in a wide range from good to poor.
Flickering lights can take a toll on occupants and their productivity. As
a result, industry groups are developing criteria to better evaluate and rate
The Impact on Occupants and Productivity
The impact of flicker on occupants can be more than annoyance, eyestrain
and complaints. A DOE study, Characterizing Photometric Flicker, reports
neurological consequences, including headaches, migraines and photosensitive epilepsy. Reductions in visual-task performance have also been
Sometimes flicker is only detected indirectly. If an object is
moving across an occupant’s gaze,
a stroboscopic effect can create
hazards, especially in industrial
settings. Indoor environments
where occupants perform reading
tasks or use video equipment may
be prone to problems.
Some people who are sensitive
to flicker may not recognize that it
is the cause of discomfort or even
consciously perceive it. Higher
levels of ambient lighting and
daylighting reduce the conscious
perception of flicker.
Poor quality power from a utility can also cause lighting flicker. Some
equipment in a building (laser printers, refrigerators, motors, etc.) may
disrupt power harmonics. Lamps can even undermine themselves.
BUILDINGS contributor Eric Woodroof found that a certain model of CFL caused
flickering of LED lamps in one of his facilities. (See his article, “Flickering
and Other LED Anomalies,” at BUILDINGS.com.)
Flicker is garnering increasing attention from lighting designers and
specifiers, the standards and specification community, and lighting manufacturers. An Institute of Electrical and Electronics Engineers group has developed a recommended practice for evaluating flicker risks, while ENERGY
STAR and California’s Title 20 require reporting of flicker performance and/
or are considering the adoption of flicker criteria.
To help specifiers measure the behavior of different lighting products,
DOE evaluated the performance of three flicker meters. The results show
that the commercial meters had similar measurement capabilities to each
other and to a reference photoelectric characterization system. However,
some differences were found when measurements were taken of light-in-tensity waveforms with significant high-frequency content greater than the
dominant 120 Hz found at full output in many products. DOE also noted that
incorrect configuration of the meters undermines accurate measurements.
ENERGY STAT: DOMESTIC ENERGY PRODUCTION WAS EQUAL TO ABOUT
89 QUADRILLION BTUS IN 2015, ROUGHLY 91% OF THE ENERGY CONSUMED IN THE U.S. THAT YEAR. THE REMAINING 9% WAS MAINLY REPRESENTED BY NET IMPORTS OF PETROLEUM.
LIGHTING FLICKER isn't just annoying – it can
cause headaches and migraines and even trigger photosensitive epilepsy.