What is the first step to take before breaking containment or opening a flange on a system that has not been worked?

To ensure safety and prevent accidents when breaking containment or opening a flange on a system that has not been worked, making sure the system is out of service and that bleeders are open and free is essential. This step is crucial because it ensures that the system is depressurized and that any residual fluids or gases can escape safely. Maintaining a safe environment during maintenance or repair work minimizes the risk of accidents such as leaks or explosive releases that could harm personnel or damage equipment.

In contrast, keeping the system energized or operational poses a direct risk to personnel working in that area. Confirming the area is clear of personnel is important, but does not address the critical need for ensuring the system's state is safe for work. Closing all valves may be appropriate in certain situations, but it does not guarantee that the system is completely depressurized and safe for maintenance tasks. Thus, the paramount first step involves ensuring the system's proper status before undertaking any work.