ASTM D5478-98(2003)

These test methods are applicable for measuring the rheological properties of varnishes and paints. In particular, the low to moderate shear rate measurements provide information related to sag resistance, leveling, etc.

1.1 These test methods cover the measurement of the viscosity of Newtonian and non-Newtonian liquids. These test methods are applicable to liquids having viscosities in the range from 5 × 10^-4 to 10³ Pas (0.5 to 10⁶ cP). The shear rate range is dependent upon the needle used and viscosity of the liquid and may vary from 10^-4 to 10³s^-1.

1.2 The yield stress of liquids having this property may also be determined.

1.3 These test methods consist of determining liquid viscosities of Newtonian and non-Newtonian fluids (clear or opaque) by measuring the steady-state (constant) or terminal velocities of cylindrical needles as they fall through the test liquid under the influence of gravity. Yield stresses of non-Newtonian liquids may be measured using the same procedure.

1.4 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.

1.5 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.