ASTM E476-87(1993)

The threshold temperature measured by this test method is an indication of the thermal instability of a chemical or mixture of chemicals, qualitatively expressed by the temperature rise. There is a potential hazard whenever the temperature of the chemical exceeds the threshold temperature unless proper design safeguards are utilized. This does not imply that temperatures lower than the threshold temperature are safe. Since this test is not an adiabatic type and does not indicate the effect of mass or time, other testing would be needed to characterize the use or storage of the chemical at lower temperatures.

Because of rate and mass dependent factors, failure to find evidence of an exothermic reaction does not ensure thermal stability unless substantiated by other test methods.

1.1 This test method is designed to determine the temperature at which a chemical or mixture of chemicals, confined initially as a solid or liquid in air or other controlled atmosphere under normal laboratory conditions, will start a reaction, generating appreciable heat when subjected to a programmed temperature increase. This test method is also designed to measure the magnitude and rate of heat generation.

1.2 This test method is for use with condensed phases.

1.3 This test method can be used over a temperature range from 0 to 500^oC, and a pressure range of 0 to 5000 psi.

1.4 As with any thermal stability test, proper safety precautions should be instituted to protect personnel. See also Section 6.

1.5 Limitations

1.5.1 The threshold temperature determined by this method may be higher than one determined by heating at a lesser rate.

1.5.2 Samples of the same material having different thermal histories may have different threshold temperatures.

1.6 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.