VISCOSITY, SAYBOLT UNIVERSAL VISCOSITY: ASTM D2161
EXPLANATION
This practice covers the conversion tables and equations for converting kinematic viscosity in centistokes (cSt) at any temperature to Saybolt Universal viscosity in Saybolt Universal seconds (SUS) at the same temperature and for converting kinematic viscosity in centistokes at 122 and 210° F to Saybolt Furol viscosity in Saybolt Furol seconds (SFS) at the same temperatures. Kinematic viscosity values are based on water being 1.0038 cSt (mm3/s) at 68° F (20° C).
A fundamental and preferred method for measuring kinematic viscosity is by use of kinematic viscometers as outlined in Test Method ASTM D445, Test Method for Determination of Kinematic Viscosity of Transparent and Opaque Liquids (and the Calculation of Dynamic Viscosity). It is recommended that kinematic viscosity be reported in centistokes, instead of Saybolt Universal Seconds (SUS) or Saybolt Furol Seconds (SFS). Thus this practice is being retained for the purpose of calculation of kinematic viscosities for SUS and SFS data which appear in past literature. One centistoke equals one millimetre squared per second mm2/s.
