Turnaround planning vs scheduling:
where planning ends and Primavera P6 begins

01Two jobs that share one name

When a planner searches for turnaround scheduling software, they usually need two different things. The first is a scheduler: a tool that holds activities, durations, logic and resources and calculates the critical path. The second is a planning system: the place where scope becomes work packages, where material is tied to the work that needs it, and where cost is estimated before a contractor mobilizes.

Primavera P6 is the scheduler on most turnarounds. It is good at that job and it should keep it. The problem is that the second job rarely has a system at all. It lives in spreadsheets, shared drives, email and the contractor's own tools, and it is rebuilt from scratch every event.

02What a scheduler does well

A scheduler answers one question: given these activities, these durations and this logic, when does each activity happen, and which ones control the end date? It does five things no planning system should try to take over.

1. Holds the activity list, durations and logic ties.

2. Calculates the critical path and float.

3. Levels resources across crews and shifts.

4. Runs what-if scenarios when scope or durations change.

5. Reports schedule progress by shift during execution.

What a scheduler does not hold is the content of the work. An activity called "Replace bundle E-301" is a bar with a duration. The scheduler does not know whether the bundle is on site, whether the work package has been reviewed, what the contractor quoted for the job, or what has been spent against it. Those answers live somewhere else, and on most turnarounds that somewhere is a spreadsheet.

03What planning is

Planning is everything that makes an activity executable. In order:

1. Scope definition and the scope freeze: what is in, what is out, and what it takes to add work after the freeze.

2. Work development: a work package per job, with the steps, the crew, the isolation and permits it depends on, and the drawings it needs.

3. Estimating: hours, crew size and cost per package, in one format across contractors.

4. Material: a requisition per package, a purchase order per requisition, and readiness tracked against the date the work needs it.

5. Contractor estimates and bids, compared line by line before award.

6. Readiness reviews at each gate, with readiness calculated from the packages rather than asserted in a meeting.

7. Field execution: progress, QA and discovery work captured where the work happens.

8. Closeout: the package closed within hours of the work, and the lessons captured for the next cycle.

The schedule is an output of planning. It is the sequencing of work that planning defined. When planning lives in spreadsheets, the schedule is sequencing work nobody can see.

04Where the handoff breaks

05A clean division of labor

06How the two should connect

Two things cross the line, and both travel the same direction: from the planning system to the scheduler. The work steps go first. The planner builds each package from the step-out library, and the steps, durations, crew and sequence go to P6 as the activities. Nobody retypes them: the scheduler is not rebuilding activities by hand from the planner's documents, and the planner is not writing them out twice. Field progress follows the same path, so the scheduler updates from what was captured in the field, not from what was recalled at the end of the shift.

EZTRAK Pilot feeds Primavera P6: the work steps from each package go to P6 as activities, and field progress follows. P6 stays the schedule of record. Nothing about the scheduler's job changes, except that the activities arrive built, and every one of them points at a package, material and cost that exist in a system.

07What to ask a vendor

1. Does your product try to replace the scheduler, or work beside it? A product that wants to own the schedule will fight the scheduling team.

2. Can the work steps in a package go to P6 as activities without anyone retyping them, and does material readiness measure against the activity date?

3. Where is field progress captured, and who types it in?

4. Do contractors work inside the system, or send files in?

5. When scope is added after the freeze, where does it show, and on what day?

6. How long until a working system exists, and is the first term month to month?

08A worked example: one exchanger bundle

Take E-301, a bundle replacement on the scope list. In the planning system it is a work package with 14 steps, a four-person crew, two permits, an isolation list and three drawings. Those steps go to P6 as the activity, 36 hours, tied to the unit's cool-down and to the crane; the scheduler sequences them, he does not type them. The bundle is a long-lead item with a 32-week lead time; the package carries the requisition, the purchase order, the promised date and the activity date the schedule needs it.

Six weeks out, the supplier slips the bundle by nine days. In the planning system that is a shortage against the activity date, visible the day the supplier says so, with the package and the contractor it affects. The scheduler moves the activity, and the crane sequence moves with it. During execution the crew records each step on a phone; when the last step closes, QA is notified at once and the package is closed the same shift. The scheduler updates from that record rather than from a radio call. At closeout the package, its material history and its cost go into the archive the next turnaround starts from.