ARCHITECTURAL SSL PRODUCT INNOVATION AWARDS
KIM LIGHTING / HUBBELL
NET ZERO BUILDINGS MAGAZINE (NZB)
RAB LIGHTING, INC.
STERNBERG VINTAGE LIGHTING
THE CONTINUING ARCHITECT
LETTERS TO THE EDITOR:
Back in the September issue, a letter from Gosia Perz raised some questions about ASSIST’s flicker research, which appeared in an SSL Interactive story on line. Our studies, cited in the ASSIST document, did not use a threshold measurement technique, but instead used measurements of how often stroboscopic effects were detected, and how acceptable they were judged even if detected. Thus, as stated in the document, extrapolating beyond the range of conditions we tested (100-10,000 Hz, 5%-100% flicker) would not yield valid predictions. I am pleased that within this range, our model predictions are correlated with data from a paper co-authored by Ms. Perz at the recent CIE Lighting Quality conference. In our studies, we also found that sinusoidal and square waveforms had similar detectability, and that a 50% duty cycle was about equally detectable as 10%.
SSL contains beautiful pictures and great lighting information, but it does not recognize that, innovative as LEDs are, there are lots of other lighting tools that might do a better job in certain applications. Even DOE cautions that LED are not for all uses. If only a small portion of the sums spent to push LEDs were allocated to R & D for incandescents, the designer’s palette would have one more way to create affordable, sustainable and acceptable lighting within the increasing energy regulations—In lighting, as in every other system, one size/type does not fit all. I particularly take umbrage with the crack in SSL Observed about HID being awful. My test kit for glass fibre optics lighting has been bounced off planes, trains, buses and cars since 1993, and the dependable metal lamp still works. Not-there-yet LEDs still have problems to solve, like questionable life time, changing color, heat dissipation, flickering on dimming and price.
JOHN BULLOUGH Lighting Research Center, RPI
GERSIL KAY, IESNA, AIA/HRC Conservation Ltg. Int’l
42 • 01.13 • ARCHITECTURAL SSL
Circle 04, 05
EQUAL TIME FLICKER FEEDBACK
In the March issue, beyond the PIA awards, we’ll present our annual look at the state of SSL manufacturing. In the continuing effort to bring down the price of the technology, manufacturers are intensely focusing on LED packaging, the aspect that accounts for the highest percentage of manufacturing cost. The community is also trying to produce light sources with fewer parts and simplified components. Check back for this notable report, as well as our usual news and technical updates.
CORRECTION: In the November 2012 profile on the Ernst and Young offices, the wattage savings were incorrect. The retrofit reduced energy from roughly 2 watts per sq. ft. to 1 watt per sq. ft., not the 40 watts per sq. ft. noted. We apologize.