Ignite Success: Ace the 2026 MCC-NH Gas Fitters Exam!

The correct first step before separating gas in a piping section for testing involves ensuring that the system is isolated from the gas supply. Closing the valves at both ends of the piping section effectively isolates that section from the rest of the gas system. This prevents any gas from entering or escaping the section being tested, ensuring safety and accuracy in the testing process.

Proper isolation is crucial because it protects both the testing personnel and any potential hazards from gas leaks during the procedure. While turning off the main supply, releasing pressure, or notifying users are important steps in the overall safety and operational protocol, they typically follow the initial isolation of the specific section that is being tested. By closing the valves first, you create a controlled environment where the testing can be safely conducted without interference from the rest of the system.