What is the primary use of plastic foam pipe insulation?

The primary use of plastic foam pipe insulation is indeed for lower temperature purposes. This type of insulation is specifically designed to help maintain the temperature of pipes carrying chilled fluids, such as those seen in refrigeration and air conditioning systems. The foam's low thermal conductivity ensures that heat transfer from the outside environment to the cold fluid inside the pipe is minimized, thus enhancing energy efficiency and preventing condensation that could lead to water damage or mold growth.

In contrast, the other options do not align with the primary application of this type of insulation. While plastic foam insulation can be used in various systems, it is not specifically installed by welders, nor is it exclusively for refrigeration piping. Furthermore, plastic foam insulation is not suitable for high-temperature applications, which would require a different material that can withstand elevated temperatures without degrading. Thus, the correct answer highlights the insulation's effectiveness in cold environments, integral to its performance and suitability in relevant applications.