Surface tension in dielectric coolants is measured as the tension between the test fluid and water (a layer of test fluid is floated on a layer of water and the tension between the two phases is measured). This is called "Interfacial Tension", and is measured per ASTM Standard Method D971. The Interfacial Tension of ElectroCool coolants is 23-25 dy/cm2 per this test method. Please contact Engineered Fluids at firstname.lastname@example.org
for more information.