rated lamp life

rated lamp life

% rated lamp life vs. % of initial lamps which survive A life expectancy curve for incandescent lamps
1. The average life of a lamp of a given type, as determined from a large sample operated under laboratory conditions; the average life of a group of lamps which are operated under variable conditions may not equal the rated lamp life.
2. For lamp types whose luminous output drops to a very low value before the lamps cease to operate: the time when the output of a large sample of lamps under controlled laboratory conditions reaches a specified fraction of the initial output.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.
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"When you group relamp, you're aiming to replace lamps at around 70 to 80% of rated lamp life. Hold back a few of the lamps that have some life still in them so that if any of the new lamps have premature failure, you have a used lamp that you can put in until the 70 to 80% mark rolls around again," Strandberg recommends.
In a group relamping program, all fixtures are cleaned and relamped at once, based on the predictable rated lamp life, just prior to the steep end of the failure curve.
Advantages for plant researchers over existing T12 and T5 fluorescent systems include energy savings up to 70 and 50 percent, respectively, greater average PPF tailored to the photosynthetic action spectrum, improved horizontal and vertical light uniformity, a dimmable ballast to adjust PPF output to 50 percent of maximum without uniformity or spectral degradation, and a 30,000-hour rated lamp life. New chambers equipped with the All-Bright 315W Greenbeams[R] will also require less air-conditioning.
Although they cost about 50 percent more than traditional metal halide systems typically used in large areas like this, they have a 75 percent longer rated lamp life and are expected to reduce the energy bills by 50 percent to 75 percent, which means they will pay for themselves in two years.
* We support the IES recommended practice of group relamping at 70 percent of average rated lamp life, which also implies the need to deliver the target illuminance through 70 percent of rated lamp life [7, pg.
The time when one half of the lamps remain operational is recorded as the "rated lamp life."
Inspire offers high performance optics, wide uniform coverage and 50,000-plus hours of rated lamp life in a compact housing.
Rated Lamp Life The 7-watt LED lamps have a 20,000-hour rated life to 70 percent of initial light output.