Abstract
In connection with various war projects some questions arose which made it necessary to design an apparatus suitable for testing the heat transmission through cylindrical samples of various kinds of thermal insulating material used for protecting hot pipes. With this apparatus the properties of spun rock wool (which is used as an alternative to magnesia) were investigated with regard to the effects of density, binder, and thickness. Other experiments were made on glass wool and corrugated asbestos. The influence of wind and the protection of the outer surface of the insulation by metallic coverings were investigated, as also was the protection of fabric coverings by paints of various kinds and colors. It was found that even bright metals such as copper and aluminum made but slight difference in the heat losses, and that most paints increased the losses as compared with those from the unpainted fabric. The details are given in the seven tables and seventeen curves accompanying this paper.
