Designation: D 2240 - 03 INTERNATIONAL Standard Test Method for Rubber PropertyDurometer Hardness1 This standard is issued under the fixed designation D 2240; the number immediately following the designation indicates the year of original adoption or, in the case of revision, the year of last revision. A number 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 Department of Defense. 1. Scope D 1349 Practice for RubberStandard Temperatures For 1.1 This test method describes twelve types of rubber Testing4 hardness measurement devices known as durometers: Types A, D 1415 Test Method for Rubber Property—Internationa B, C, D, D0, E, M, O, 00, 00O, 000-S, and R. The Hardness4 procedure for determining indentation hardness of substances D 4483 Practice for Determining Precision for Test Method classified as thermoplastic elastomers, vulcanized (thermoset) Standards in the Rubber and Carbon Black Industries4 rubber, elastomeric materials, cellular materials, gel-like ma- F 1957 Test Method for Composite Foam Hardness- terials and some plastics is also described. DurometerHardness 1.2 This test method is not equivalent to other indentation 2.2 ISO Standards: hardness methods and instrument types, specifically those ISO/IEC 17025: 1999 General Requirements for the Com- described in Test Method D 1415. petence of Testing and Calibration Laboratories6 1.3 This test method is not applicable to the testing of 3. Summary of Test Method coated fabrics. 1.4 The values stated in SI units are to be regarded as 3.1 This test method permits hardness measurements based standard. The values given in parentheses are for information on either initial indentation or indentation after a specified only. Many of the stated dimensions in SI are direct conver- period of time, or both. Durometers with maximum reading indicators used to determine maximum hardness values of a sionsfromtheU.S.CustomarySystemtoaccommodatethe instrumentation,practices and procedures that existed prior to materialmayyieldlowerhardness whenthemaximumindi- the Metric Conversion Act of 1975. cator is used. 1.5 All materials, instruments, or equipment used for the 3.2 The procedures for Type M, or micro hardness durom- determinationofmass,forceordimensionshallhavetraceabil- eters, accommodate specimens that are, by their dimensions or ity to the National Institute for Standards and Technology,or configuration,ordinarily unable tohave their durometer hard- otherinternationallyrecognizedorganizationparallelin nature nessdeterminedbythe otherdurometertypes described.Type 1.6 This standard does not purport to address all of the M durometers are intended for the testing of specimens having safety concerns, i if any, associated with its use. It is the a thickness or cross sectional diameter of 1.25 mm (0.050 in.) or greater, although specimens of lesser dimensions may be responsibilityoftheuserofthisstandardtoestablishappro- successfully accommodated under the conditions specified in priate safety and health practices and determine the applica- bility of regulatory limitations prior to use. Section 6, and have a Type M durometer hardness range of between 20 and 90. Those specimens which have a durometer 2. Referenced Documents hardness range other than specified shall use another suitable 2.1 ASTM Standards: procedure for determining durometer hardness. D 374 Test Methods for Thickness of Solid Electrical Insu- 4. Significance and Use lation? D 618 Practice for Conditioning Plastics for Testing3 4.1Thistestmethod isbased onthepenetrationofa specific D 785 Test Method for Rockwell Hardness of Plastics and type ofindentorwhenforced intothematerial underspecified Electrical Insulating Materials3 conditions. The indentation hardness is inversely related to the penetration and is dependent on the elastic modulus and viscoelastic behavior