This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. Designation: D575 - 91 (Reapproved 2018) INTERNATIONAL Standard Test Methods for Rubber Properties in Compression1 This standard is issued under the fixed designation D575; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. Anumber in parentheses indicates the year of last reapproval. A superscript epsilon (e) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the U.S. Department of Defense. 1. Scope specimen upon application of a compressive force. The two 1.1 These test methods cover two test procedures for deter- different procedures are as follows: 3.1.1 Test Method A-Compression Test of Specified mining the compression-deflection characteristics of rubber Deflection-A compression test in which the force required to compoundsotherthanthoseusuallyclassifiedashardrubber and sponge rubber. cause a specified deflection is determined. 3.1.2 Test Method B-Compression Test at Specified 1.2 The values stated in SI units are to be regarded as the Force-A compression test in which the specified mass or standard. The values given in parentheses are for information compressive force is placed on the specimen and the resulting only. deflection is measured and recorded. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the 4. Significance and Use responsibility of the user of this standard to establish appro- 4.1 These test methods are useful in comparing stiffness of priate safety,health,and environmental practices and deter- rubbermaterials in compression.Theycanbeusedbyrubber mine the applicability of regulatory limitations prior to use. technologists to aid in development of materials for compres- 1.4 This international standard was developed in accor- sive applications. dance with internationally recognizedprinciples on standard- ization established in the Decision on Principles for the 5.Apparatus Development of International Standards, Guides and Recom- 5.1 Compression Testing Machine-A compression testing mendations issued by the World Trade Organization Technical machine conforming to the requirements of Practices E4, and Barriers to Trade (TBT) Committee. having a rate of head travel of 12 ± 3 mm/m (0.5 ± 0.1 in./min), may be used for either type of test. Any other type 2. Referenced Documents machine that will meet these requirements may be used. For 2.1 ASTM Standards:2 example, a platform scale equipped with a yoke over the D3183 Practice for Rubber—Preparation of Pieces for Test platform and a hand-operated screw to apply the force will Purposes from Products serve if it will conform to the requirements prescribed for D3767 Practice for Rubber-—Measurement of Dimensions accuracy and rate of travel. Compression tests at specified D4483 Practice for Evaluating Precision for Test Method forces may be performed on any machine that applies minor Standards in the Rubber and Carbon Black Manufacturing andmajorforcesgently,withoutimpact,orbyplacing speci- Industries fied masses gently on the specimen. The machine shall be E4 Practices for Force Verification of Testing Machines equipped to permit measurement of the deflection caused by the increase from minor force to major force. 3. Summary of Test Methods 5.2 Deflection Gage-The deflection shall be read on a gage 3.1 These tests constitute one kind of compression stiffness of dial type graduated in hundredths of millimetres (or thou- measurement. Deflection is the change in thickness of the sands of an inch). 5.3 Micrometer-The thickness of