This practice covers procedures for conditioning electrical insulating materials (although not necessarily to equilibrium) prior to testing and the conditions under which they shall be tested. In general the physical and electrical properties of electrical insulating materials are influenced by temperature and relative humidity in a manner that materially affects test results. In order that reliable comparisons may be made of different materials and between different laboratories, it is necessary to standardize the humidity and temperature conditions to which specimens of these materials are subjected prior to and during testing.

Formerly under the jurisdiction of Committee D09 on Electrical and Electronic Insulating Materials, this guide was withdrawn in November 2012 and replaced by Standard Practice D618 on Conditioning Plastics for Testing.

Conditioning of specimens may be undertaken: (1) for the purpose of bringing the material into equilibrium with normal or average room conditions; (2) simply to obtain reproducible results; or (3) to subject the material to abnormal conditions of temperature or humidity in order to predict its service behavior. However, it is not within the scope of this practice to define procedures for determining aging characteristics of electrical insulating materials.

The conditioning procedures prescribed in this practice are designed to obtain reproducible results and may give values somewhat different from values under equilibrium at normal conditions, depending upon the particular material and test. To ensure substantial equilibrium under normal conditions of humidity and temperature, however, may require many days or weeks depending upon thickness and type of material and its previous history. Consequently, conditioning for reproducibility must of necessity be used for general purchase and product control tests.

Any reference to this practice must include the information needed for designating the conditioning procedure (and testing procedure, if applicable), as defined in Section 7, or one of the standard conditioning procedures to be followed, as defined in Section 8.

1.1 This practice covers procedures for conditioning electrical insulating materials (although not necessarily to equilibrium) prior to testing and the conditions under which they shall be tested. In general the physical and electrical properties of electrical insulating materials are influenced by temperature and relative humidity in a manner that materially affects test results. In order that reliable comparisons may be made of different materials and between different laboratories, it is necessary to standardize the humidity and temperature conditions to which specimens of these materials are subjected prior to and during testing.

1.2 This practice is similar to Practice D 618.

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 and health practices and determine the applicability of regulatory limitations prior to use.