Abstract :
All incoming materials used for insulating purposes have to comply with specifications or the special requirements of designers. This paper deals briefly with the details associated with the control of incoming materials, together with some special features associated with tests which have to be carried out in order that the performance of the materials under special conditions can be ascertained. To achieve this work special testing apparatus has been designed from time to time, and brief reference is made to some of the problems which have to be solved in order to ensure that the insulating materials selected will fulfil the performances required. Suggestions are also made dealing with the question of finding substitutes for insulating materials in short supply, and some of the new materials introduced for this purpose are mentioned.
