Seasonal Plant Shutdown and Restart Sequence SOP

Step-by-step procedure for safely shutting down plant systems for a seasonal production pause, preserving equipment during the idle period, and restarting systems in the correct order.

Steps

• Confirm shutdown scope and authorization
  The operations supervisor verifies the shutdown scope, affected systems, planned outage window, and restart owner. The supervisor confirms required approvals, permit-to-work needs, and any customer or production commitments that may be affected. The supervisor records the final authorization in the shutdown log and notes any deviations from the standard sequence.
• Notify affected teams and secure the work area
  The operations supervisor notifies production, maintenance, quality, and utilities teams of the shutdown timing and expected duration. The supervisor posts warning signage, sets barricades where needed, and confirms that only authorized personnel remain in the controlled area.
• Stop the process in the planned sequence
  The operator stops upstream and downstream equipment in the documented shutdown order. The operator allows each unit to reach its normal stop condition before moving to the next step. The operator records any alarms, abnormal noise, vibration, or process instability and escalates deviations immediately.
• Isolate energy sources and apply lockout/tagout
  The maintenance technician isolates electrical, pneumatic, hydraulic, thermal, and mechanical energy sources as applicable. The technician applies locks and tags, releases stored energy, and verifies isolation using the approved test method. The technician documents any energy source that cannot be fully isolated and escalates the non-conformance to the supervisor.
• Depressurize, drain, and clean affected systems
  The maintenance technician depressurizes vessels and lines in the approved order, confirming pressure is within site tolerance before opening any component. The technician drains fluids, removes residual product, and cleans process surfaces or strainers as required by the equipment manual. The technician records any trapped material, blocked drain, or abnormal residue and escalates if the condition cannot be corrected.
• Preserve equipment for the idle period
  The maintenance technician applies the approved preservation method for each asset, such as lubrication, desiccant placement, protective covering, or sealed openings. The technician verifies that vents, drains, and access points are secured according to the equipment-specific preservation plan. The technician records preservation actions in the maintenance log.
• Document shutdown status and outstanding deviations
  The operations supervisor reviews the completed checklist, confirms all critical steps are closed, and records any open work orders, deviations, or follow-up actions. The supervisor attaches photos where required and assigns an owner and due date for each unresolved item. The supervisor signs off the shutdown record.
• Inspect equipment before restart
  The maintenance technician inspects the equipment for corrosion, leaks, loose fasteners, blocked drains, missing guards, and abnormal wear. The technician confirms that preservation materials are removed or adjusted as required for operation and that all access panels are secured. The technician escalates any defect that could affect safe restart.
• Restore utilities and energize systems in reverse order
  The maintenance technician removes lockout/tagout devices only after authorization and verification that the area is clear. The technician restores utilities and energizes systems in the reverse order of shutdown, allowing each system to stabilize before proceeding. The technician monitors pressure, temperature, current draw, and other critical indicators against site tolerance.
• Verify stable operation and release the plant for service
  The operations supervisor verifies that equipment runs normally, alarms are cleared, and critical process values remain within tolerance for the required observation period. The supervisor confirms that all temporary controls are removed, the area is clean, and outstanding issues are documented. The supervisor records final release to service and communicates restart completion to affected teams.