What is the minimum air test required for water-supply systems, other than plastic piping?

• A. 30 psi
• B. 40 psi
• C. 50 psi
• D. 60 psi

Answer: (C)

The minimum air test required for water-supply systems, excluding plastic piping, is 50 psi. This specific pressure is set to ensure that the system can handle the necessary stresses without leaks or failures.

Conducting the test at 50 psi is significant because it assesses the integrity of the joints, fittings, and the overall piping system under pressure. It ensures that all connections are secure and that the system can perform effectively once put into service. A higher minimum pressure than required could potentially risk damaging components or lead to erroneous conclusions about the system's integrity. Therefore, the 50 psi standard strikes a balance that ensures safety and reliability while being appropriate for various materials used in plumbing that are not plastic.