Saybolt Universal Second

Saybolt Universal second (Often SUS or SSU) is a measure of kinematic viscosity used in classical mechanics. It is the time that 60 cm³ of oil takes to flow through a calibrated tube at a controlled temperature. The SUS is used for oils with flowing time up to 5600^{[citation needed]} seconds, in the range of low to medium viscosity such as machine oils.

When the flowing time surpasses 5600^{[citation needed]} seconds, Saybolt Furol second should be used instead of Saybolt Universal second. The tube diameter in the two scales is such that the Furol viscosity is one-tenth of the Universal viscosity:

$\text{Saybolt Furol viscosity} = \frac{\text{Saybolt Universal viscosity}}{10}$

Calculation of the SUS is specified by the ASTM D2161 specification.

External links

• Online viscosity convertor
• Measurement apparatus
• Useful Saybolt reference
• About Saybolt units