American Society of Mechanical Engineers (ASME) Practice Exam 2026 - Free ASME Practice Questions and Study Guide

The correct choice is based on established testing protocols for safety valves. Safety valves are critical components in various systems, designed to prevent overpressure and ensure safety by releasing excess pressure. To effectively test a safety valve by hand, the pressure applied should be significant enough to ensure that the valve operates as intended.

Testing at 75% of the set pressure is a commonly accepted standard because it provides a reliable indication of the valve's ability to open and close under actual operating conditions. This level of pressure is necessary to confirm that the valve's performance aligns with its designed specifications and to verify its response to overpressure situations.

The other options, while they may represent practical levels of pressure for some evaluations, do not meet the criteria established for comprehensive testing. Lower percentages, such as 50% or 35%, might not sufficiently challenge the valve or demonstrate its full operational capabilities, leading to uncertainty regarding its performance and reliability during actual service conditions. Testing at 25% of set pressure is particularly inadequate, as it is too low to ensure the valve will function properly under real-world scenarios. Therefore, 75% of the set pressure is the minimum pressure required for conducting a thorough and effective hand test of a safety valve.