2014 IES Street and Area Lighting Conference
September 14-17, 2014 | Nashville, TN
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After an evaluation of relevant light pollution standards and guidelines, 58 on-premise commercial signs were photometrically measured and the results assessed. Signs included internally, externally, and channel lighted varieties. The majority of signs measured fell below photometric levels believed to be associated with light pollution.
A file format is proposed for the electronic transfer of five classes of spectral data: spectral power distributions from commercial light sources, spectral power distributions from theoretical illuminants, spectral reflectance distributions, spectral transmittance distributions, and spectral weighting functions. Examples of practical files are provided.
An instrument is described for the far-field photometric testing of skylights. A frame rotates about a vertical axis that passes through the skylight. The frame supports six mirrors and 10 photocells that provide direct and reflected flux paths at 10 measurement angles between nadir and 85 degrees. Each position of the frame generates an azimuthal plane of data. The acquisition, application, and limits of the data are discussed.
The performance of daylight-responsive, photosensor control in five daylighted classrooms was simulated with Radiance. The daylighting systems included windows, lightshelves, clerestories, and skylights. The electric lighting included direct and indirect systems. Different photosensor positions and fields-of-view were used in the simulations and their effects on the tracking of daylight levels with the room were analyzed. Energy analysis of different dimmed lighting zones control schemes showed the daylight savings that can be achieved.
A summary history is provided of the development of industrial photometry from its earliest beginnings to 1909. It is shown that the need for photometry paralleled technological changes and competition within the lighting industry. Emphasis is placed on the rarely documented history of photometric concepts and the development of photometric practice that resulted. Finally, a review of the standards of light and photometric instrumentation used during this period is given.