Project Code of Accounts — Process
A beginner's guide to the code of accounts for process industries — the general coding system tuned to how process plants are organized: by process area, by equipment, and by the disciplines that build them. Built on AACE International RP 21R-98.
What this standard adds
Everything from Lesson 2 still holds — a multi-field code, estimate and actuals aligned, the backbone of cost reporting. What 21R-98 adds is the process-specific structure: the natural breakdowns a process plant organizes around, so the code matches the deliverables (PFDs, equipment lists) and methods (equipment-factored estimating) you met in the Cost Estimating track.
How process plants are coded
- Process area / unit — The plant divides into process units and areas (and ISBL vs OSBL); a primary coding dimension.
- Equipment — Major equipment items (tagged) anchor process cost — so equipment is a natural code element.
- Discipline — Process, mechanical, piping, instrumentation, electrical, civil — the disciplines that execute the work.
- Cost type — Labour, material, equipment, subcontract — as in the general code (Lesson 2).
A process code, field by field
| Field | Example | Meaning |
|---|---|---|
| Area / unit | 200 | Reaction unit |
| Equipment / commodity | V-201 | A specific vessel (or a bulk commodity) |
| Discipline | PIP | Piping |
| Cost type | L | Labour |
Putting it to work
For a process project, structure the code of accounts around process areas, equipment, and disciplines, keep ISBL/OSBL distinguishable, and align it with the factored estimate so planned and actual share the breakdown. The result feeds clean, plant-shaped cost reports that managers of each unit and discipline can act on.
Nine things to remember
- 21R-98 tailors the code of accounts to process plants — same backbone, process structure.
- It codes by process area/unit, equipment, discipline, and cost type.
- Coding should match the estimating method — equipment- and area-based, like factored estimates.
- Equipment is a natural code element — it anchors process cost.
- The discipline dimension echoes the process estimate plan — consistent across the controls chain.
- ISBL/OSBL must be distinguishable in the code — or reports can't separate them.
- Align it with the factored estimate so planned and actual share the breakdown.
- It feeds plant-shaped reports that unit and discipline managers can act on.
- One code, many industries — universal principles, sector-specific structure.
Glossary
- Bulk commodity
- Piping, cable, etc. coded by commodity.
- Code of accounts (process)
- Cost coding structured around a process plant.
- Cost type
- Labour, material, equipment, subcontract.
- Discipline
- Process, piping, instrumentation, civil, etc.
- Equipment tag
- A unique identifier for a piece of equipment.
- Estimate alignment
- Matching code structure to the estimate.
- ISBL / OSBL
- Inside / outside battery limits.
- Process unit / area
- A section of the plant — a primary coding dimension.