Illuminating Engineering Society, Association of Public Lighting Engineers (Great Britain) · [London] · leaf 606
e ceiling. Fig. 1 shows(he comiiarative overall lengths of percentage of the total light producedreaching the actual working plane.This figure was found to vary from27 to 30 per cent. The effect of accu-mulations of dirt and dust in reducingthis efficiency is very striking; forexample, at the end… … Fig. 1.—Comparative dimensiocs of various modern electrical illuminants.{Apyroximate scale 1 in, = 2/t.) various modern electric lamps, whichdiffer remarkably in this respect. Witha low ceiling some of these lamps mightbe inadmissible. Figs. 2-4 illustratesome typical forms of ceiling construc-tion…
Lighting
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