Polymeric outdoor insulation

The need for resistance to surface tracking and erosion partially differentiates outdoor insulation from indoor insulation. A review of the current status of development of standards for testing these properties worldwide on materials and components is presented. Of special interest is the self-restoration of the hydrophobicity of some materials, most notably silicones, after the hydrophobicity has been removed by surface arcing. Since the accelerated tests are continuous, the restoration is not permitted, while in real life it is. This is important because silicones are among the best candidates for outdoor insulation in severely polluted areas. This means that new and different test methods must be developed. It is emphasized that it is important to integrate this information with the old in order to plan future work. Other requirements of outdoor insulation are discussed