When working with pressurized systems, what must be done before service?

Before servicing pressurized systems, it is crucial to ensure that the system is depressurized and isolated. This process significantly mitigates any risk of accidents or injuries that could occur due to sudden releases of pressure, which can happen in a live system. By depressurizing, you eliminate the potential for explosive decompression or hazardous leaks when the system is accessed. Additionally, isolating the system helps prevent any unintended flow of fluids or gases while work is being conducted, further protecting both the workers on site and the integrity of the system itself.

Other options do not provide adequate safety measures. For instance, relying solely on visual inspections does not account for underlying risks that may not be visible. Starting service immediately without taking necessary precautions could lead to dangerous situations. Simply notifying workers to step back does not address the fundamental need for safe isolation and depressurization, which are essential steps before any maintenance or service can be safely performed.