Full definition
A scheduled and pre-arranged temporary cessation of production for the specific purpose of performing preventive maintenance, major inspections, equipment upgrades, repairs identified by predictive maintenance, and regulatory compliance activities that cannot be performed while the equipment is operating. Planned shutdowns (also called turnarounds in process industries) are dramatically more cost-effective than unplanned shutdowns because: parts are pre-ordered (standard pricing, no premium), labor is scheduled (no overtime premium), work is pre-planned (detailed scope, procedures, and sequence), safety preparations are thorough (permits, LOTO, confined space), and production can build buffer inventory in advance. Planning horizon: annual major shutdowns (1-4 weeks for process plants), quarterly mini-turnarounds, and regular shift shutdowns for routine PM. Critical path method (CPM) and project management techniques optimize shutdown duration — every hour of planned shutdown still costs lost production. Typical activities during planned shutdowns: bearing and seal replacements, belt and chain replacements, alignment verification, vessel inspections (API 510, API 570), safety system testing, calibration, and cleaning. Per ISO 55000 (asset management), API 510/570 (inspection intervals), and plant-specific turnaround procedures.