This practice covers the procedures for calculating the viscosity index of water glycol hydraulic fluids, and related materials from their kinematic viscosities at 20 and 80C. The two determined viscosities for the sample fluid are plotted. A straight line drawn through the two points and intersecting the vertical chart line indicates the temperature of 100C. Reading across on the y axis of the chart the kinematic viscosity at this intersection point as the viscosity of the sample fluid at 100C is determined. Using the determined viscosity of the sample fluid at 100C obtained in Step1. and determining the viscosity of the sample fluid at 40C ASTM D 2270 -04 is used to calculate the viscosity index of the sample fluid.
Water glycol hydraulic fluids are the most used type of FRHF in the world. Due to it's composition; containing significant amounts of water, determination of the kinematic viscosity at 100C required for determination of the viscosity index is inaccurate.
Keywordsfire-resistant hydraulic fluid:
The title and scope are in draft form and are under development within this ASTM Committee.Back to Top
Draft Under Development