BS 6712-2:1991 PDF

What is BS 6712-2 - Hygroexpansivity measurement of paper and board about?

The measurement of dimensional changes in paper and board with changes in the ambient humidity is necessary for accurate control of printing and similar processes. The change in length, or hygroexpansivity, is due to stress relaxation of the paper fibres and swelling or contraction of the fibres by absorption or desorption of water. The proportion of the two mechanisms effective to produce hygroexpansivity depends upon the upper limit of relative humidity of the environment. BS 6712-2 is identical to ISO 8226-2 . BS 6712-2 specifies a method for the determination of the hygroexpansivity of paper and board when subjected to a change in the relative humidity with which it is in equilibrium from (33 ± 2) % to (84 ± 2) %. The method provided in