ISO 13820:2014 Paper, board and corrugated fibreboard — Description and calibration of compression-testing equipment
Introduction
This International Standard describes the types of testing equipment available for carrying out compression tests on paper, board, and corrugated fibreboard. It describes two distinct types of instrument. The preferred instrument type, known as the fixed-platen compression tester, develops compressive forces at a constant rate of strain. The other, known as the beam-deflection compression tester, develops compressive forces between one platen driven at constant speed and another platen resting on a deformable beam. With this type neither rate of stress nor rate of strain is constant. The two instrument types give similar but not necessarily the same test results when used for compression tests; literature shows that the beam deflection machine produces results higher than those of the fixed-platen machine.[1][2][3] The extent of the difference depends on the test being conducted and on the characteristics, particularly the elastic characteristics, of the material being tested.
The fixed-platen tester is preferred because of its better reliability, its ability to test over the range of test levels likely to be found, and because the characteristics of existing instruments have been well defined and universally accepted. The beam-deflection tester has been inadequately defined in past International Standards for compression tests; among existing instruments there have been different loading rates, different beam stiffnesses, and therefore different rates of strain. Furthermore, in some countries, the stiffness of beams commonly available is such that no one beam is appropriate for all the test levels likely to be found, so that it has been common practice to use two beams of different stiffnesses interchangeably to cover the full range of loads.
It is expected that the beam-deflection-type tester might be less commonly used in the future, and it can be withdrawn from this International Standard at a future revision.
The testing equipment referred to in this International Standard is used for tests described in ISO 3035, ISO 3037, ISO 7263, and ISO 12192.
Scope
This International Standard specifies the essential characteristics and the principles of calibration of compression testing equipment used in the testing of paper, board, and corrugated fibreboard.
Normative references
The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.