Piping between the vacuum pump and the source shutoff valve shall be permitted to be which materials?

• A. Brass pipe
• B. Galvanized steel pipe
• C. Black steel pipe
• D. All of the above

Answer: (D)

Piping in the vacuum line just upstream of the source shutoff valve must be able to endure suction, be durable, and be compatible with the vacuum service. Brass, galvanized steel, and black steel all meet these requirements, so they are all acceptable choices for this portion of the system. Brass is corrosion-resistant and easy to thread, making it convenient for smaller lines and fittings. Galvanized steel provides good corrosion resistance and cost-effectiveness for larger pipes. Black steel is strong, widely used for gas and vacuum piping, and easy to join with standard fittings. Because this segment is upstream of the shutoff valve and designed to carry vacuum, these materials are suitable, which is why all of the above are permitted.