What is generally a required action before draining a fuel line?

Before draining a fuel line, one of the primary safety precautions is to close the valves. This action is essential to prevent any potential leaks or spills that could occur during the draining process. Closing the valves ensures that fuel does not flow into the area where it is being drained, minimizing the risk of exposure to hazardous materials and enhancing safety for personnel handling the task.

While checking fuel quality, notifying a supervisor, and measuring fuel quantity are important considerations in fuel system maintenance, they are not the immediate actions taken before the actual process of draining a fuel line begins. These steps may be part of the overall maintenance procedure but do not specifically pertain to the direct preparation needed for draining a fuel line, where valve closure is crucial for safety and containment.