Artificial lighting in poultry houses: Are photometric units appropriate for describing illumination intensities?

Abstract

Abstract 1. The quality and the quantity of poultry house lighting are important. Many research projects have been centred on temporal aspects of this illumination and on its spectral distribution ('colour') and illumination intensity. For this purpose illumination is measured at floor‐level in photometric units (lux or cd/m2). 2. The relevance of these measurements depends on an equivalence of the domestic fowl and the human photopic spectral sensitivity curves, because the latter (CIE) type of curve is the basis of photometric units. 3. A comparison of the data on domestic fowl spectral sensitivity and the CIE‐data, however, shows a serious discrepancy. For most purposes in poultry research, therefore, the lux‐meter is not an appropriate instrument. 4. A better way of presenting the relative luminance of a lamp for domestic fowl ('galluminance') is by multiplying the spectral power distribution of the lamp (Eλ)—as documented by the manufacturer— by the relative spectral sensitivity distribution of the domestic fowl (Gλ). 5. For this purpose we present the log Gλ data in relative units per 5 nm.