ASTM D1909-13

4.1 The value listed for the commercial moisture regain and commercial allowance of a specific fiber type is not an experimentally determined quantity but a purely defined value arrived at for commercial purposes by interested parties. The actual moisture regain values of textile materials, when in moisture equilibrium with the standard atmosphere for testing, can deviate from the listed values. Equilibrium moisture regain values depend upon the previous history of the material. The actual finish content of textile materials can deviate from the listed values (see Test Method D2494).

1.1 These tables list the commercial moisture regains and commercial allowances commonly used for a number of textile fibers. Such moisture regain and allowance values are intended primarily for determining the commercial weight of a specific fiber when the fiber is bought or sold on this basis. These regain and allowance values also are used in calculating the linear density of yarn in procedures employing such factors and in the quantitative analysis of fiber blends.