1.1 This test method covers the determination of the flow time (viscosity) of Newtonian and near-Newtonian paints, and related coatings and products using ISO capillary flow cups.

Note 1—If the liquid is non-Newtonian, that is shear-thinning or thixotropic, Test Methods D2196 should be used.

1.2 The cup-orifice combination (ISO cup with orifice diameter of 3 mm, 4 mm, 5 mm, or 6 mm) is selected to provide an efflux time with the range of 20 to 100 s and viscosities up to 700 cSt (700 mm²/s). The most commonly used cup is the one with the 4-mm orifice.

1.3 This test method is limited to testing materials for which the breakpoint of the flow from the orifice of the flow cup can be determined with certainty. This point is difficult to determine and reproduce for materials with flow times in excess of 100 s due to slowing-down effects.

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

1.5 This standard does not purport to address 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.

Note 2—The International Civil Aviation Organization (ICAO) and the International Maritime Organization (IMO) include in their regulations a similar test (ISO 2431) to determine the viscosity of hazardous viscous liquids. The viscosity is then used to place these liquids in a hazard packaging group depending on their viscosity/flashpoint relationship. The U. S. Department of Transportation permits the use of these regulations for transhipment of hazardous material within the U.S. when bound for foreign destinations.