Saybolt Universal Second (SSU or SUS) and Saybolt Furol Second (SSF or SFS)
Saybolt Universal Second (SSU or SUS) and Saybolt Furol Second (SSF or SFS) :
Units of kinematic viscosity given by readings on Saybolt viscometers. The Saybolt Universal viscometer is used for liquids having viscosities below 1000 centistokes (or 10 stokes, see entry for stokes below). The Saybolt Furol viscometer is used for more viscous road and fuel oils ("furol" is an acronym for fuel and road oils). In both cases the reading is the time, in seconds, for 60 milliliters of a sample to flow through the device. The Furol viscosity readings are roughly 1/10 the Universal readings. For liquids whose viscosity exceeds 50 centistokes at 37.8 °C (100 °F) one SSU is approximately 0.2158 centistokes or 0.2158 mm2/s. For very viscous liquids (viscosity exceeding 500 centistokes) at 50 °C (122 °F), one SSF is approximately 2.120 centistokes or 2.120 mm2/s. Exact equations were published in 1996 by the American Society for Testing and Materials (ASTM practice D2161). The Saybolt seconds are considered obsolete, but they have been used traditionally in the petroleum industry and are common in technical articles
