The moisture content of many materials is commonly determined by oven-drying, the change in mass of the material being assumed to be due solely to removal of water. In the case of paper products and pulp this assumption is incorrect. Volatile constituents other than water may be lost in oven-drying and oxidation or decomposition of some constituents is possible at high temperatures.The quantity of water removed depends on the method of drying adopted. In oven-drying the moisture values obtained are to some extent dependent on the temperature used, the humidity in the oven and also on the time of drying.When other methods of water removal are used, for instance vacuum desiccation or distillation or extraction with solvents, moisture content values do not always agree with those obtained by an oven-drying method.The moisture content of paper products and pulps must therefore always be defined in terms of a particular method. This Standard describes the two main procedures.The method of sampling for determination of moisture content is critical and the relevant Standard, AS 1301.417s-1992 Methods of test for pulp and paper, Method 417s: Sampling paper, board and pulp for testing, fully describes the procedure required.NOTE 1 - When information is required on variations in moisture content between the centre and edges of sheets or across a reel, a number of test pieces must be cut in a pattern decided by the information required. A scheme for this is described in ISO 287:1985.