CLASSIFICATION OF INSULATING MATERIALS
1. Classification according to substances and materials.
2. Classification according to temperature.
Classification according to substances and materials :
(i) Solid Insulating Materials [Inorganic and organic] Mica, wood, slate, glass, porcelain, rubber, cotton, silk, rayon, terylene, paper and cellulose materials etc.
(ii) Liquid Insulating Materials [Oils and Varnishes] Refined hydrocarbon minerals oils, Linseed oil, spirit and synthetic varnishes, etc.
(iii) Gaseous Insulating Materials Dry air, carbon dioxide, argon, nitrogen, etc.
Classification according to temperature
The insulating materials are classified mainly based on the thermal limit. The performance of the insulation depends on its operating temperature. The higher the temperature, the higher will be the rate of its chemical degrading, and hence the lower will be its useful life as shown in figure. If a reasonably long life of insulation is expected, its operating temperature must be maintained low. Therefore, it is necessary to determine the limits of temperature for the insulation, which will ensure safe operation over its expected life.
Thus the insulating materials are grouped into different classes Y, A, B, and C with
temperature limits of 90 0C, 1050C and 1300C for the first three classes and no specific limit
Classification according to temperature
The insulating materials are classified mainly based on the thermal limit. The performance of the insulation depends on its operating temperature. The higher the temperature, the higher will be the rate of its chemical degrading, and hence the lower will be its useful life as shown in figure. If a reasonably long life of insulation is expected, its operating temperature must be maintained low. Therefore, it is necessary to determine the limits of temperature for the insulation, which will ensure safe operation over its expected life.
Thus the insulating materials are grouped into different classes Y, A, B, and C with
temperature limits of 90 0C, 1050C and 1300C for the first three classes and no specific limit
