5.1 Data obtained by this test method shall not be used to predict the behavior of materials at elevated temperatures except in applications in which the conditions of time, temperature, method of loading, and stress are similar to those specified in the test.

5.2 This test method is particularly suited for quality control and development work. The data are not intended for use in design or predicting endurance at elevated temperatures.

5.3 Ruggedness testing indicates that some materials, such as poly (vinyl chloride) exhibit substantially greater imprecision than that described in Section 14 for “well behaved” materials.

1.1 This test method is applicable to high modulus materials that soften upon heating to a modulus less than 6.0 MPa. This test method describes the determination of the temperature at which the specific modulus of either 6.65 MPa (Method A) or 33.3 MPa (Method B) (equivalent to Test Method D1525) of a test specimen is realized by indentation measurement using a thermomechanical analyzer as the test specimen is heated. This temperature is identified as the indentation softening temperature. The test may be performed over the temperature range of ambient to 300 °C.

Note 1: This test method is intended to provide results similar to those of Test Method D1525 but is performed on a thermomechanical analyzer using a smaller diameter indenting probe. Equivalence of results to those obtained by Test Method D1525 has been demonstrated on a limited number of materials. Until the user demonstrates equivalence, the results of this Test Method shall be considered to be independent and unrelated to those of Test Method D1525.

1.2 This test method is not recommended for ethyl cellulose, poly (vinyl chloride), poly (vinylidene chloride) and other materials having a large measurement imprecision (see Test Method D1525 and 5.3 and Section 14).

1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.5 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.