This International Standard specifies two methods of measur-ing the thicknes of paper and board and of calculating the ap-parent bulk density or the apparent sheet density from the thickness determinations. The methods are
a) measurement of single sheets of paper or board (single sheet thickness);
b) measurement of a pack of sheets of paper of grammage up to 224 g/m2 (bulking thickness).
These methods are not applicable to corrugated fibreboard and, in the case of method b), not to certain soft papers such as tissues which are creped and/or embossed, due to the slow or excessive compression which takes place when measurements are made on such materials.
It should be noted that two alternative pressures are permitted (see table 1); the pressure of 100 kPa ± 10 kPa is preferred.
NOTE — It should be noted that the two methods generally lead to dif-ferent results.
DS/EN 20534:1993 history
1993DS/EN 20534:1993 Paper and board. Determination of thickness and apparent bulk density or apparent sheet density