This article focuses on the interaction of thermal radiation with water droplets and the creation of water mist for the purpose of evaluating the decrease of heat flux when positioning a water curtain of various parameters between a radiation source and a radiometer. The change of water curtain parameters, affecting the passing through of thermal radiation, was performed using five nozzles with a variable spray characteristics. For the respective nozzles the attenuation of thermal radiation was determined and the thermal radiation transmittance was calculated. Water mist was created using a high-pressure pump and nozzles with a different size of the orifice. The measurement of droplet size was performed using the time-shift technique. The Omegalux radiant panel was used as the radiation source and the Hukseflux SBG01 radiometer with a working range of 0-5 kW.m(-2) was used as the detector. (c) 2017 American Institute of Chemical Engineers Process Process Saf Prog 37:18-24, 2018