ASTM D6080 : 12

1.1 This practice covers all hydraulic fluids based either on petroleum, synthetic, or naturally-occurring base stocks. It is not intended for water-containing hydraulic fluids.

1.2 For determination of viscosities at low temperature, this practice uses millipascal·second (mPa·s) as the unit of viscosity. For reference, 1 mPa·s is equivalent to 1 centipoise (cP). For determination of viscosities at high temperature, this practice uses millimetre squared per second (mm²/s) as the unit of kinematic viscosity. For reference, 1 mm²/s is equivalent to 1 centistoke (cSt).

1.3 This practice is applicable to fluids ranging in kinematic viscosity from about 4 to 150 mm²/s as measured at a reference temperature of 40°C and to temperatures from −50 to +16°C for a fluid viscosity of 750 mPa·s.

1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.