Ignite Success: Ace the 2025 MCC-NH Gas Fitters Exam!

The correct choice emphasizes the importance of leaving valves and fittings exposed during pressure tests for examination. This is crucial because valves and fittings are potential points where leaks can occur due to their configuration and the connection to piping systems. Inspecting these components during a pressure test allows for direct observation and verification of their integrity under pressure.

By having these components exposed, any signs of leaks, weaknesses, or failures can be readily identified and addressed before the system is put into operation. Valves, in particular, have moving parts that may not seal properly under pressure, and fittings can face stresses that might not be present when the system is not pressurized. This proactive approach ensures safety and reliability in gas fitting installations.

While all the other choices—pipes and joints, sealing materials, and appliances and meters—are important to the integrity of a gas system, the focus of pressure testing is particularly on the points where control and directional changes occur, which are found in valves and fittings.