scope:

This Standard describes the procedure for general use for the conditioning of paper; the procedure for conditioning handsheets for the physical testing of pulp is given in AS/NZS 1301.208s. The term 'paper' is used in this standard in the general sense to include paperboard and corrugated fibreboard, except when the specific use of the term is apparent.

The physical properties of paper are affected materially by its moisture content which, in turn, is dependent on the humidity of the surrounding atmosphere. In order that tests may be made on paper in a stable physical state it is brought from a dry state into equilibrium with an atmosphere of standardized temperature and relative humidity and tested in that atmosphere.

NOTE 1 - Although the establishment of moisture equilibrium is generally adequate to ensure that paper is in a stable physical state, it is possible that the strength or some other property may not have reached equilibrium as soon as moisture content. In such a case the conditioning process should be prolonged until the desired physical equilibrium is attained. It is good practice to postpone the testing for as long as is practical after the moisture content has reached equilibrium.

The moisture content of paper in equilibrium with a given atmosphere varies according to whether the equilibrium is reached by absorption or desorption of moisture. Since physical properties that change with moisture content are affected by this hysteresis, the equilibrium condition must be attained by an absorptive process such that the moisture content approaches - or is identical with - the paper's lower isotherm moisture content [1] and [2].

Whilst any atmosphere may be selected for special purposes or agreed upon by those concerned in the testing, the atmosphere which is defined in AS/NZS 1301.415s is the standard atmosphere for use with the AS/NZS 1301 series of testing standards.