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ISO 12625-3 Caliper




ISO 12625-3


Determination of thickness, bulking thickness and apparent bulk density


Thickness is an important property of tissue paper and tissue products.

In the tissue industry, thickness-related parameters, such as the roll diameter of rolled products (kitchen towel) or the stack height of folded products (paper towels) are often measured. However, the fact that not only end-use tissue products, but also the base tissue paper from which these products are made, is the subject of trade between companies and countries, means that there is a genuine need for a consistent measure of thickness that can be applied to tissue products at any stage of their manufacture.

The thickness of tissue paper and tissue products is known to be dependent on the pressure applied to the material at the time of measurement. Several different loading pressures, pressure-foot diameters and loading speeds have been used within the tissue industry. This part of ISO 12625 has been prepared by harmonizing those standards applicable to tissue and tissue products currently in use. It specifies a single loading pressure, foot diameter and loading speed to be used for all thickness measurements of tissue and tissue products.


ISO 12625-3 Caliper specifies a method for the determination of thickness and bulking thickness and the calculation of apparent bulk density and bulk of tissue papers and tissue products under a pressure of 2,0 kPa.

This part of ISO 12625 has been developed to provide a consistent test method for the determination of thickness and density of tissue paper and tissue products. Corresponding test methods for paper and board in general are covered in ISO 534.


Measurement of the thickness of a test piece of tissue paper sampled during the manufacturing process, or a tissue product supplied as a finished article.  The measurement is made as the distance between a fixed reference plate on which the sample rests and parallel pressure-foot that exerts a specified load on the area under test.


Method includes calculation for Apparent Bulk Density; Basis weight required for calculation. Client to specify if single sheet or bulk thickness is to be measured.


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