ASTM D341-93(1998) PDF

1.1 The kinematic viscosity-temperature charts covered by this standard are a convenient means to ascertain the kinematic viscosity of a petroleum oil or liquid hydrocarbon at any temperature within a limited range, provided that the kinematic viscosities at two temperatures are known.

1.2 The charts are designed to permit petroleum oil kinematic viscosity-temperature data to plot as a straight line. The charts here presented provide a significant improvement in linearity over the charts previously available under Method D341-43. This increases the reliability of extrapolation to higher temperatures.