While polyurethane is an excellent insulator, and the most efficient medium for low to medium temperature applications, it is not suitable for applications over 110 °C. Permapipe has developed a system to insulate for higher temperature applications such as steam.

Rockwool is an excellent insulator for higher temperature applications, so a Rockwool-polyurethane combination was utilised. Rockwool sections were installed onto the pipe, wrapped in reinforced silver foil and inserted into an outer case. Polyurethane was injected into the space between the Rockwool and the case. Steel spacers were welded to the pipe to ensure the pipe remains concentric to the case.

Rockwool has a safe working temperature up to 650 °C. This system is ideal for steam and other high temperature applications.