Which of the following is NOT a method of pipe insulation?

Plastic coating is not typically recognized as a method of pipe insulation. The primary purpose of pipe insulation is to reduce heat loss or gain, prevent condensation, and protect pipes from freezing.

Foam sleeves are a common insulation material that provides thermal resistance and is designed specifically to fit around pipes, forming a continuous layer of insulation. Fiberglass wrap is another effective insulation option, often used for its insulating properties as well as its ability to cover complex shapes and sizes of piping systems. Mineral wool is also a recognized insulation material that offers excellent thermal and acoustic insulation. Each of these materials serves specific functions in preventing energy loss and protecting piping systems, demonstrating their suitability for insulation purposes.

In contrast, while plastic coating can serve to protect pipes from external environments, it does not function as a thermal insulator in the same way that the other materials do. Its primary use is often related to corrosion resistance or surface protection rather than insulation.