1.1 The viscosity-temperature chart covered by this standard is a convenient means of plotting data for estimating the viscosity of asphalts at any temperature within a limited range. Conversely, the chart may be used to ascertain the temperature at which a desired viscosity is attained.

1.2 The chart is suitable for original asphalt cements and for asphalts recovered from laboratory aging tests or extracted from pavements.

1.3 The chart is based on a viscosity–temperature relationship that can be plotted using any appropriate set of units. For convenience, charts based on both conventional and SI units are provided.

1.4 The range of the chart is sufficient for roofing asphalts.

1.5 The range of the chart is sufficient for liquid asphalts (bitumens) whose viscosity exceeds 0.01 Pa.S (10 centipoise).

1.6 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.