Tehran University of Medical Sciences International Journal of Occupational Hygiene 2008-5109 7 1 2015 10 14 17 21 EN FARAMARZ MADJIDI Department of Occupational Hygiene Engineering, School of Health, Zanjan University of Medical Sciences, Zanjan, Iran. 2015 10 14 2015 10 14 High intensity optical radiation can cause damage to the eye and intense radiation in the range of 770-1400 nm can cause thermal retinal damage. In the workplaces where there are high temperature sources, the workers in front of these hot  sources without bright light maybe exposed to the  intense IR radiation, thus regular measurement of these radiations seems crucial. Measurement of IR radiations by radiometer in  specific wavelength ranges is elusive. Moreover, when radiometers are used, the correct application of the recommended exposure limits requires knowledge of spectral radiance which seems sophisticated for hygienists. The main objective of the present study is applying a model to express retinal thermal injury in terms of temperature for molten aluminum ovens in an aluminum foundry that emit optical radiation without visible light. In the proposed model, ACGIH TLVs for retinal thermal injury in the range of 770 to 1400 nm was used where source luminance was under 0.01 cd/cm2. Also, by using the output results of this proposed model it is possible to present a new chart for evaluation of exposure to IR for hot sources based on Threshold Temperature. https://ijoh.tums.ac.ir/index.php/ijoh/article/view/124 https://ijoh.tums.ac.ir/index.php/ijoh/article/download/124/150