Massachusetts 3rd Class Engineer Practice Exam 2026 – Complete Prep Guide

During a hydrostatic test, safety valves should be removed or gagged to ensure accurate test results and to avoid any potential damage or malfunction. The hydrostatic test involves filling the system with water and applying pressure to check for leaks and structural integrity. If safety valves are left in place or not properly secured, they could open at their set point due to the increased pressure, leading to a false indication of a leak or causing a dangerous situation.

Removing or gagging the safety valves prevents them from inadvertently releasing pressure during the test, allowing the testing process to assess the system's strength without interference. Once the hydrostatic test is complete, safety valves can be reinstated to ensure proper operation.