Relation of Transformer Design to Fire Protection [includes discussion]

This contribution to the discussion of the fire risks of transformers is limited to tests on the materials which enter the apparatus and their probable behavior. Comparisons are made regarding flammability of the solid insulations, as well as the gases evolved from them. These gases are analyzed for chemical composition and volume, and calculations made regarding their probable action in a transformer. The flammability characteristics of the various classes are shown to overlap to a considerable degree, especially for the insulation classes B and H. This emphasizes the fact that insulation classes are intended to define temperature limitations as regards aging, but do not necessarily classify flammability.