In this paper, we propose a technique for calculation of the thickness. This technique is allowed to determine the thickness of a sleeping bag based on data on the equivalent coefficient of thermal conductivity of a sleeping bag package and data of heat production of person during the sleep. The values and trends in the variation of the relative discrepancy between the calculated and experimental thickness of the sleeping bags as a function of temperature are explained by the possible differences in the data on the thermal conductivity of the down, and by the necessity to introduce thermal insulation coefficients for individual parts of the body.

Keywords: Key words: sleeping bag thickness, down, thermal conductivity, thermal insulation

The article presents a systematic analysis of the habitat of waterfowl eider ducks, goose, geese and ducks, whose down is used in the production of thermal protective clothing and equipment. On the basis of the analysis, the hypothesis that the difference of the elastic properties of feather mass Northern species birds eider ducks and geese from domestic birds living in relatively comfortable temperatures. The method of experiment to determine the relaxation properties of textiles in a cylindrical cell. Conducted study of the relaxation properties of down masses of different types of birds depending on the temperature, which showed higher relaxation down masses of eider ducks and geese at low temperatures. A large mass of down, the diameter and shape of the barbs and tendrils, the number of tertiary structures indicate that the eiderdown has to be extremely elastic and resistant to stress. The results of experimental studies on the rheological properties of the feather down raw materials of water birds. Levels of regenerative abilities on the initial thickness of textile cells filled with fluff, recommendations on the use of down-feather mixtures in thermal protective clothing in various price categories.

Keywords: Key words: feather down insulation, thermal protective clothing, textile cell, filling the capacity of the fluff, the rheological properties of down, the relaxation properties of down, loading-unloading, aeration