ASTM D8240-22

1.1 This specification covers less-flammable (high fire point) synthetic ester insulating liquids for use as a dielectric and cooling in new and existing electrical power apparatus including power and distribution transformers, switchgear, and other associated equipment.

1.2 Synthetic ester insulating liquids differ from conventional mineral oil and other less-flammable (high fire point) liquids in that they are products derived from the chemical reaction, processing, and physical treatments of a carboxylic acid and an alcohol.

1.3 This specification is intended to define synthetic ester electrical insulating liquids that are compatible with typical materials of construction of existing apparatus and are expected to maintain their functional characteristics in these applications. The material described in this specification is not always miscible with other electrical insulating liquids. The user should contact the manufacturer of the synthetic ester insulating liquid for guidance in this respect.

1.4 This specification applies only to unused synthetic ester insulating liquids as received prior to any processing. The user should contact the manufacturer of the equipment or liquid, or both, if questions of recommended characteristics or liquid maintenance procedures arise.

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