Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 213
in Fig. 9. Referring to the polar diagram, Fig. 10,the total flux from lamp and shade is39x4:r=490 lumens. The mean of the angles subtended bythe top of the gallery at the lamps on thetwo sides is about 70°, and the total fluxunder this angle is 2irX 50*5=317.Hence the utilisation factor is, 317490… … III Church lighted by tungsten lamps in prismatic ul.i-- reflecton THE ILLUMINATING ENGINEER (apku.) 199 A value of the mean horizontal illu-mination over the central area, whichwill be rather an under-estimate, can beobtained by considering the lights movedon to the long centre line of the…
Lighting
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