IS 13383 : Part 3 : 1992 Photometry of Luminaires - Methods of Measurement - Part 3 : Luminaires for Floodlighting

1 Scope

1.1 This standard (Part 3) is intended to cover the photometryof floodlights used for interior and exterior lighting purposes andequipped with incandescent or discharge (including tubularfluorescent) electric lamp or with reflector lamps. Therecommendations relate to visually steady light and not to aflashing light.

1.2 The photometric measurements described in this standardrelate to determining the luminous intensities in the projectedbeam which may be presented as a luminous intensity distributiondiagram, iso-candela diagram or in tabulated form suitable for usein computer calculation. These intensities are deduced fromilluminance measurements, the inverse square law of distances beingsupposed verified (see 4.4.2). In some instances the measurement ofother photometric quantities may be more appropriate, as forexample the distribution of illuminance over a plane which may berelatively close to the luminaire such as with a `wall washer' typeluminaire. Such measurements are not dealt with in the report andwill be covered in a separate Standard.

1.3 The photometric techniques recommended do not include thephotometric of projectors for signaling purposes, road lightinglanterns, vehicle headlights (some of which are covered by otherdocuments) nor `image-forming' optical devices, although similartechniques may well be used for the photometry of such devices. Insome cases recommendations may be prepared by other committees.

1.4 Light beams, in which the angle between the peak and the onehalf peak intensity direction is less than 2�C(that is 2 x 2�C, or 4�C to onehalf peak divergence for a symmetrical beam), require specialmethods of photometry which are not included.