ASTM D8634-25

1.1 This test method covers the method for determining the conductivity of coolant samples for use in electric vehicles (EV) using a conductometer.

1.2 This method is applicable to ethylene glycol and propylene glycol-based coolants and mixtures of it within a temperature range of 20 °C to 30 °C.

1.3 The conductivity range should be within 0.1 µS/cm up to 300 µS/cm.

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

1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

5.1 Electrical conductivity is a critical physical property for thermal management fluids with intended use in electrical applications such as battery electric and fuel cell vehicles. A fluid’s electrical conductivity is used to assess its compatibility and safety with these systems, and therefore accurate measurement of this property is necessary.