CECS — Maintenance Turnarounds (Process)
A whole project squeezed into a shutdown. This is the most different estimate-classification variant: a turnaround estimates a dense bundle of maintenance tasks on a running plant, where an estimate's maturity rides on how frozen the worklist is and how well the inevitable discovery work is allowed for. Built on AACE 112R-20.
What this standard adds
This is the most different variant in the module. Where the others estimate new assets defined by engineering deliverables, a turnaround estimates a dense bundle of maintenance tasks on an existing plant. "Project definition" here means the worklist: how many jobs, how well scoped, and how firmly committed.
Why turnarounds are distinctive
- Schedule is everything — every day the plant is down is lost production worth a fortune, so turnarounds are ruthlessly time-boxed, and cost is tightly coupled to duration.
- Thousands of small tasks — scope is a vast list of discrete jobs rather than a few big deliverables, estimated bottom-up from the worklist.
- Discovery work is guaranteed — opening vessels and equipment reveals corrosion and damage you couldn't see while running, adding scope mid-event.
- Scope freeze is critical — a firm cut-off date for adding planned work is essential; late additions wreck both estimate and schedule.
Worklist development mapped to classes
Turnaround maturity climbs as the worklist is built, reviewed, and frozen (general pattern; the RP gives the authoritative matrix):
| Class | Worklist state | Typical method |
|---|---|---|
| 5 | Turnaround scope concept, history-based | Top-down from past turnarounds |
| 4 | Preliminary worklist, major jobs known | Worklist + large discovery allowance |
| 3 | Worklist developed, being reviewed | Job-by-job buildup + allowance |
| 2 | Worklist near-frozen, jobs detailed | Detailed task estimates |
| 1 | Frozen worklist, fully planned | Full bottom-up estimate |
Putting it to work
For a turnaround estimator, the class reflects how complete and frozen the worklist is, plus the confidence in the discovery allowance. Drive toward an early, firm scope freeze, size the discovery allowance from inspection data and history, and treat lost-production cost as part of the picture — because in a turnaround, schedule and cost are the same conversation.
Nine things to remember
- 112R-20 applies the five-class system to turnarounds — anchored to the worklist.
- It's the most different variant — maintenance of a running plant, not new build.
- The worklist is the scope — its completeness and freeze set the class.
- Schedule is everything — downtime is lost production; cost tracks duration.
- Scope is thousands of discrete tasks — estimated bottom-up from the worklist.
- Discovery work is guaranteed — allow for found damage from history and inspection.
- Scope freeze is critical — late additions wreck estimate and schedule.
- Scope creep is the killer — a still-growing worklist isn't a mature estimate.
- One framework, many dialects — turnarounds redefine "definition" as a frozen worklist.
Glossary
- Discovery / found work
- Extra work revealed once equipment is opened.
- Discovery allowance
- Budget set aside for expected found work.
- Estimate class
- Maturity level (5 roughest → 1 most definitive).
- Lost production
- Revenue forgone while the plant is down — a key cost.
- Scope freeze
- The cut-off date after which no planned work is added.
- Shutdown / outage
- Other names for the planned downtime event.
- Turnaround (TAR)
- A planned plant shutdown for maintenance and overhaul.
- Worklist
- The catalogue of all jobs to be done in the turnaround.