Piping between the vacuum pump and the source shutoff valve shall not be made of which material?

The piping between the vacuum pump and the source shutoff valve must not be made of plastic materials, such as PVC, primarily due to concerns regarding durability, pressure resistance, and compatibility with the vacuum system's requirements. Plastic piping, while lightweight and generally easy to work with, is not capable of withstanding the potential stresses and strains of a vacuum environment. It may also not provide the required strength and integrity under varying temperatures and may be susceptible to degradation over time from exposure to chemicals or other environmental factors associated with medical gas systems.

In contrast, materials such as black steel, galvanized steel, and stainless steel are commonly used in vacuum piping because they possess the necessary strength, resistance to corrosion, and ability to maintain structural integrity under vacuum conditions. These materials ensure a reliable and safe operation within medical gas installations, which is critical for maintaining the efficacy of the vacuum system used in healthcare settings.