Full definition
Planned total stoppage of a plant or process unit to perform major maintenance, mandatory regulatory inspections (pressure vessels, boilers) and process modifications not feasible during operation. Typical duration: 2-6 weeks every 2-5 years per regulation. Planning: 12-18 months in advance with detailed scope, engineering, parts, contractors and critical-path schedule. KPIs: cost vs. budget, actual days vs. planned, additional scope (scope creep). Reference standard: ASME PCC-2 for in-plant repairs.