Piping between the vacuum pump and the source shutoff valve is permitted to be which of the following materials?

The appropriate choice for piping between the vacuum pump and the source shutoff valve is brass. This is due to several important properties of brass that make it suitable for such applications. Brass is a strong and durable metal that has good resistance to corrosion and is capable of withstanding the pressures typically found in vacuum systems.

Additionally, brass connections and joints can be reliably sealed, which is crucial in vacuum applications to maintain integrity and prevent leaks. The thermal conductivity of brass also helps in dissipating heat that may be generated during the operation of the vacuum pump.

In contrast, materials like plastic may not have the required strength or may degrade over time due to exposure to heat or chemicals, while aluminum, although lightweight and resistant to oxidation, can be less durable under certain pressures and may react adversely with some gases. Fiberglass, while also a strong material, typically isn’t used in this context due to its brittleness and challenges in forming reliable seals compared to metals. This reinforces the suitability of brass as a material for piping in vacuum applications.