Besides comfort and hygiene of textile materials sufficient barrier properties, such as protection against ultraviolet (UV) irradiation, are also often required. For the evaluation of barrier properties of textile materials against UV irradiation, a quantitative expression, "ultraviolet protection factor (UPF)", is used. This factor correlates with the time period of human skin protection against UV irradiation in the open air. One of the experimental methods for quantitative UPF evaluation involves a spectrophotometric method of fabric testing. This paper describes a novel modification approach to transfer this method to non-woven and non-knitted fabrics. The aim of the transformation was to modify the used method to determine barrier properties of polymer composite fibres so that the measurement could be simplified while keeping the reliability of the obtained results. As a testing material samples of polypropylene fibres with dispersed nanoTiO(2) filler reeled on the sheet-metal frame were used. The results show that this modified method gives reliable results and is suitable for development of new kinds of fibres with higher barrier protection against UV irradiation.