Chapter 5 - Ground Crew Supplement

Refractometer Use in Determining a Glycol Based Fluid's Freezing Point

26.  The freezing point can be measured directly, using a method such as ASTM D 1177, however, this method is cumbersome for use in the field. The freezing point of fluids can be easily monitored in the field by measuring their refraction. The magnitude of the refraction is related to the concentration of glycol contained in the solution and therefore to the fluid freezing point.

27.  The fluid manufacturers should be consulted for further operational information on the procurement and the training required for refractometer use in the field.