Significant factors in thermal aging tests on flexible sheet insulation

THE revision of the present temperature classification of insulating materials as in AIEE Standard No. 11 seems increasingly necessary to accommodate insulation application practice and apparatus temperatures to the higher temperature at which some of the newer synthetic materials seem to be safely operable. It has been the goal of the Working Group on the Evaluation of the Thermal Stability of Insulating Materials which was set up in the Basic Science Subcommittee on Dielectrics to develop acceptable standard methods of evaluating the thermal stability of insulating materials. Such methods should put any revision of the present standards onto a rational and conservative basis.