BS 7463-7 is identical to ISO 9184-7. The BS 7463 series focuses on Fibre furnish analysis of paper, board and pulps. BS 7463-7 specifies two methods namely the comparison method and fibre coarseness method for determining the weight factor of fibres used in the fibre furnish analysis of paper, board and pulp. In BS 7463-7, the weight factor is obtained either by a comparison method or by calculating fibre coarseness.
BS 7463-7 is applicable to all kinds of fibres of pulps from unmixed wood species. In this context, it means pulps that do not contain more than 5 % of other fibres with an essentially different weight factor.
BS 7463-7 on the determination of fibres weight factors is useful for:
Weight or substance per unit area, called basis weight, is a fundamental property of paper and paperboard products. The weight factor is a specific dimensionless quantity for each kind of fibre. It is the ratio of the mass per unit length of a particular kind of fibre to that of a reference fibre with a mass per unit length of 0,180 mg/m.
BS 7463-7 provides you with methods to calculate the weight factor, which is calculated from the fibre coarseness as described in BS 7463-6 for the determination of fibre coarseness. Chemical softwood pulps with weight factors in the range from 0,9 to 1,1 have been analysed for the repeatability of the comparison method at the Finnish Pulp and Paper Research Institute by several operators using several instruments.
BS 7463-7 helps to calculate the density or specific gravity of paper from the weight factor of fibres used in fibre finish analysis of paper and pulp.
ISO 9184-7:1994