In this study, a thermal protective performance (TPP) test was applied for thermal analysis. The thermal analysis by the TPP test was carried out on the single layer-fabrics and their assemblies in two- and three-layerconstructions. The thermal protective performance ratings of these constructions and each single outer layer fabrics were determined Thickness and area mass seem to influence the TPP ratings of single-layer fabrics. Four types of outer layer fabrics and one type of third-layer fabric were also tested in the Du Pont Engineering Fibres Laboratory. The results obtained in our laboratory were compared with Du Pont test results. Also, each fabric was washed 1, 3, 5, and 10 times. TPP ratings, air permeability, area masses and tear strengths of fabrics were measured before and after certain washing cycles. Dimensional changes at the end of washing were also determined The highest TPP ratings were obtained from the three-layer (outer layer + thermal barrier + inner layer) structures. According to the results,fabrics shrink, air permeability values and tear strengths were decreased, and the area mass of test samples increased with the increase in the number of washing cycles. Washings cause a decrease in TPP ratings of single-layer fabrics and an increase in TPP ratings of multi-layer constructions.