ISO 29681:2009 (R2025)

ISO 29681:2009 specifies a method for the determination of the pH of an aqueous extract of paper, board and pulps, in which the soaking and the measuring are performed in salted water (0,1 M KCl solution). ISO 29681:2009 is applicable to all kinds of paper, board and pulps, but is specifically applicable to bleached pulps from virgin fibres and to pulp samples having a low ionic strength for which the pH-value using this International Standard will give more realistic results related to mill conditions than those obtained with ISO 6588-1 or ISO 6588-2.