this paper deals with the changes occurring in the protective resistant, service and product-safety properties of work clothing and protective clothing materials during washing. the products were tested by sfs standard methods or by other methods in general use involved in this study were 23 industrially made work and protective clothing materials of various fire-safety classes. the materials were divided into six groups: cotton materials, polyester/cotton materials, filamentary-surface materials, materials woven out of fire-resistant fibers, coated materials, and wool-like materials. all the materials were washed in water, but a few were also washed chemically. measurements made after various numbers of washings showed that the properties changed in different ways on materials from the different groups, which must be taken into account when combining several materials into one product. the properties of the materials generally changed more in water washing than in chemical washing. 21 refs. in finnish