本部分规定了当纸张或纸板的相对湿度从（33 2）%变化到（84 2）%时，测定湿膨胀性的方法。目的是涵盖拟在高湿度条件下使用的纸和纸板的应用。它还可用于确定在某些印刷过程中，纸张可能短时间受到的过多水分的影响。该方法普遍适用。但不适用于cr pe纸和瓦楞纸板。

This part specifies a method for the determination of hygroexpansivity when the paper or board is subjected to a change in the relative humidity with which it is in equilibrium from (33 2) % to (84 2) %. The purpose is to cover applications of paper and board intended to be used in high humidity conditions. It may also be useful in determining the effect of excessive moisture to which paper may be subjected for short periods during some printing processes. The method is generally applicable. However, it is not suitable for cr pe papers and corrugated fibreboard.