A turnaround (TAR) is a scheduled event wherein an entire process unit of an industrial plant, such as a refinery, petrochemical plant, power plant, or paper mill, is taken offstream for an extended period for work to be carried out. Turnaround is a blanket term that encompasses more specific terms such as I&Ts (inspection and testing), and maintenance. Turnaround can also be used as a synonym of downtime.
Related terms are shutdowns, and outages[1] sometimes written as Turnarounds, Shutdowns, and Outages (TSO).[2]