Specifies characteristics of synthetic organic esters intended for use as insulating liquids in transformers and other electrical equipment. Gives general guidance on their properties, safety, storage and disposal, and requirements for packaging, labelling and sampling. Describes test methods to test the physical properties. Specifies required characteristics of synthetic organic esters intended for use in transformers and capacitors. The contents of the corrigendum of December 1993 have been included in this copy.