How to Schedule a Plant Turnaround or Outage in Primavera P6

A turnaround schedule has a different job than a capital project schedule. The window is short, the work runs around the clock, and every hour the unit is down costs production. The schedule has to be detailed enough to manage by the shift and simple enough that supervisors actually use it.

How a Turnaround Schedule Differs

• Durations in hours, not days
• 24-hour calendars and shift-based crews
• Scope frozen before the shutdown begins
• Updates every shift instead of every month
• Shutdown and startup sequences owned by operations
• Discovery work found only after equipment is opened

Those differences change how the schedule is built, how often it is statused and how the critical path is managed.

Start With a Frozen, Challenged Worklist

The schedule can only be as good as the scope behind it. Each worklist item should be reviewed to confirm it really requires the unit to be down. Then it needs a job plan, an estimate and a responsible contractor. After the scope freeze date, late additions should go through a change process so the team can see what each one does to the window before approving it.

Build the Schedule From Job Plans

Each major job should follow the same pattern so the schedule is consistent and easy to read. A typical sequence includes:

• Isolation, blinding and permits
• Scaffolding and insulation removal
• Opening and cleaning
• Inspection
• Repair or replacement
• Closing, testing and deblinding

Coding each activity by unit, equipment tag, contractor, craft and job number lets the team filter the same file into crew-level work lists, contractor lookaheads and management summaries.

Plan for Discovery Work

Inspections will find work no one could scope in advance. Rather than ignoring it, the schedule should identify which equipment is most likely to grow and what repair would typically follow. It should also show where that growth would affect the critical path. Some teams carry contingent repair activities or allowances for high-risk items. Either way, the team should know before the shutdown which inspection results could threaten the return-to-service date.

Include Shutdown and Startup

The turnaround does not start when the first flange is broken. Shutdown, cooldown, draining, decontamination, steam-out, isolation and handover to maintenance all take time. They often sit on the critical path. So do leak testing, deblinding, handback and restart. These sequences belong in the schedule, built with operations, because they decide when maintenance can start and when the unit can produce again.

Set Calendars and Critical Resources

Turnaround work usually runs on 24-hour calendars with day and night shifts. Some resources can control the schedule even when the logic does not: heavy-lift cranes, specialty contractors, bundle extractors, confined-space attendants, inspectors and scaffold crews. They should be loaded and checked so the plan does not depend on more of them than the site will actually have.

Know the Critical Path Before Shutdown

Before the unit comes down, the team should know which jobs make up the critical path and which paths sit just behind it. In petrochemical and refining units, these are often major exchangers, fired heaters or furnaces, columns, reactors and large rotating equipment. These jobs deserve the best planning, the most experienced crews and the closest tracking.

Update Every Shift

During execution, the schedule is only useful if it is current. A shift-based update cycle collects progress from supervisors and statuses the schedule. It then reruns the CPM calculation and reports the critical path, near-critical work and any new discovery work before the next shift meeting. Pathline has supported shift-based progress reporting built around that rhythm.

Emergency Outages Need a Faster Approach

An unplanned outage has no long planning cycle. The scheduler builds a working framework quickly. It is usually organized around the shutdown, the known repairs and the restart, and it expands as inspections define the scope. On a 90-day emergency LNG outage, Pathline’s founder served as Lead Scheduler while all three trains were worked in sequence, carrying crews and lessons from one train to the next.

Capture Lessons for the Next Turnaround

Actual durations, discovery rates and resource bottlenecks from one turnaround are the best inputs for the next. Feeding them back into job-plan templates is how repeat outage schedules get more accurate over time. That is the approach behind Pathline’s founder’s work as Lead Scheduler on numerous Gulf Coast ethylene unit outages.

Frequently Asked Questions