This test method covers the empirical procedures for determining the Saybolt Universal or Saybolt Furol viscosities of petroleum products at specified temperatures between 21 and 99°C (70 and 210°F). Special procedures for emulsified asphalts and waxy products are indicated. Note—AASHTO T 201 and ASTM D445 are preferred for the determination of kinematic viscosity. These methods require smaller samples and less time, and provide greater accuracy. Kinematic viscosities may be converted to Saybolt viscosities by use of the tables in ASTM D2161. It is recommended that viscosity indexes be calculated from kinematic rather than Saybolt viscosities.