2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
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The 10th edition of the IES Lighting Handbook will contain a new illuminance determination procedure. This article frames these recommendations within an historical context and describes how they are responsive to modern aspects of lighting practice. The new procedure: 1) has more categories with finer steps; 2) provides a method for 1interpreting whether the target value is a minimum, average, or maximum; 3) includes uniformity targets; 4) permits activity levels to be accounted for in outdoor environments; 5) accounts for occupant age; 6) provides a method to adjust photopic illuminance targets for conditions of mesopic adaptation; and 7) accounts for outdoor environmental constraints with the use of lighting zones. This new illuminance determination procedure has been approved by the IES Board of Directors.
Most lighting simulation programs represent color as RGB triplets in a device-dependent color space such as ITU-R BT.709. Implicit in this representation is the assumption that interreflections between colored surfaces can be accurately calculated using three separate color bands. We demonstrate that while this assumption generally holds for most architectural finishes, it can result in substantial prediction errors for saturated colors
The objective of this study was to explore how calibrated high dynamic range (HDR) images (luminance maps) acquired in real world daylit environments can be used to characterize, evaluate, and compare visual comfort conditions of innovative facade shading and light-redirecting systems. Detailed (1536 x 1536 pixel) luminance maps were time-lapse acquired from two view positions in an unoccupied full scale testbed facility. These maps were analyzed using existing visual comfort metrics to quantify how innovative interior and exterior shading systems compare to conventional systems under real sun and sky conditions over a solstice-to-solstice test interval. The results provide a case study in the challenges and potential of methods of visualizing, evaluating and summarizing daily and seasonal variation of visual comfort conditions computed from large sets of image data.
The IEEE Standards Working Group, IEEE PAR1789 "Recommending practices for modulating current in High Brightness LEDs for mitigating health risks to viewers" has been formed to advise the lighting industry, ANSI/NEMA, IEC, EnergyStar and other standards groups about the emerging concern of flicker in LED lighting. This paper intends to introduce new measures and definitions of lamp flicker in lighting. The discussion represents on-going work in IEEE PAR1789 that is vital to designing safe LED lamp drivers.