3.1 The magnitude of the changes in the electrical properties of the insulating oil are of importance in determining the contamination of the oil by the test specimen.

3.2 Physical and chemical changes in the oil such as color, interfacial tension and acidity, also indicate solubility or other adverse effects of the test specimen on the oil.

3.3 Physical changes of the test specimen such as hardness, swelling, and discoloration show the effect of the oil on the test specimen and are used to determine the suitability of the material for use in insulating oil.

3.4 A material meeting the criteria recommended does not necessarily indicate suitability for use in electrical equipment. Other properties must also be considered. Additionally, certain materials containing additives may meet the requirements of these test methods, yet be unsatisfactory when subjected to longer term evaluations. Examples of such materials are polyvinyl chloride (PVC) based compounds, nylon and elastomeric compounds.

1.1 These test methods cover screening for the compatibility of materials of construction with electrical insulating oil for use in electrical equipment.

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

1.3 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.

1.4 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.