This Standard is included in DIN Handbook 398. Rotational viscometers are used to measure dynamic viscosity with a definite speed gradient which may, however, vary in amount and period of effect, i.e. flow curves are recorded. Restricted to Newtonian fluids; most quantitative relations change on transition to non-Newtonian fluids. The stipulations apply subject to the prerequisites listed below (for terms see Section 2). Deviations from this will lead to errors, correction of which, insofar as they can be detected, is dealt with.