Pitch does not go through a solid-liquid phase change when heated and therefore does not have a true melting point. As the temperature is raised, pitch softens and becomes less viscous. The softening point is arbitrarily defined and must be determined by a closely controlled method that must be carefully followed if test results are to be reproducible.

This test method is useful in determining the consistency of pitch as one element in establishing the uniformity of shipments and sources of supply.

1.1 This test method covers the determination of the softening point above 80°C [176°F] of pitch. Test Method D 3104 gives comparable results.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.

1.3 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 and health practices and determine the applicability of regulatory limitations prior to use.