Every refinery invests a tremendous amount of time and money in planning a unit turnaround. Scheduling of the tasks, manpower and equipment has to be detailed and thorough. In order to plan, information is needed about the process system so that critical tasks can be planned to meet turnaround time constraints. Some of this condition-based information is gathered using tools such as gamma scans, radiography, ultrasonic probes, vibration monitors, acoustic sensors, and other non-destructive techniques whilst the process is still operating. It is vital to be aware of any internal damage to distillation columns, heat exchangers, reactors, and other vessels to avoid surprises that can disrupt the turnaround schedule. Each day of downtime is a day of lost production, so it is critical that a turnaround is not extended due to unexpected repair work.