Operation
An operation is the ISA-88 procedural level between unit procedure and phase — a complete processing activity that takes material from one stable state to another within a single unit. Granulation, drying, crystallisation, fermentation, compression: each is an operation.
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The operation is the level at which most batch records are organised, because it is the granularity that matches how process scientists and operators actually think about the work.
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01What an operation is
ISA-88 defines an operation as the procedural element below the unit procedure and above the phase. The defining property is that it takes material from one stable, well-defined state to another — pre-blend to post-blend, wet granulate to dry granulate, fermentation broth to harvested cell paste — within a single unit.
Operations are the natural reporting unit. When a process scientist asks "how long does drying take?", the answer is per-operation, not per-phase. When QA samples mid-batch, it samples at operation boundaries. When an IPC is plotted on a CPV control chart, the chart is per-operation.
02Why this level matters
- Process science thinks per-operation — formulation development, scale-up and tech transfer happen at this granularity.
- Batch records are organised per-operation — review-by-exception scans operation-level summaries first, drilling into phases only on flags.
- IPCs and CPPs are anchored at operation boundaries — sample taken "at end of granulation", not "at phase 3.2.1.4".
- Process timing metrics (cycle time, yield per operation) are the natural KPIs for operations and engineering.
- Tech transfer documents ("how this product is made") describe operations; phases are the implementation detail.
03Operation vs phase
The line is sometimes blurry. Useful heuristic:
| Aspect | Operation | Phase |
|---|---|---|
| Outcome | Material state change | Equipment-level action |
| Owner | Process science | Controls / automation |
| Reusability | Recipe-specific composition | Library-reusable building block |
| Duration | Minutes to hours/days | Seconds to minutes |
| State machine | Composite of phases | ISA-88 phase state model |
| Examples | Granulation, Drying, Crystallisation | Charge, Heat, Hold, Discharge |
Operations compose phases the way recipes compose operations: as named, ordered, conditionally-branched sequences.
04Composition rules
- Operations call phases from the phase class library, not inline code.
- Operation start and end conditions are explicit — "start when previous operation completes AND unit clean", "end when product CQA verified".
- Operations declare their material-state precondition and postcondition for the genealogy graph.
- Operations declare their IPC sampling points explicitly so the sampling plan can be derived from the recipe.
- Operations carry a defined nominal duration for scheduling; runtime captures actual duration for CPV.
05Cross-industry examples
- OSD pharma — Dispense, High-Shear Granulation, Fluid-Bed Drying, Milling, Lubrication Blend, Compression, Film Coating, Pack.
- API — Reagent Charge, Reaction, Quench, Workup, Crystallisation, Filtration, Wash, Drying.
- Biopharma — Inoculum Prep, N-1 Expansion, Production Fermentation, Harvest, Clarification, Capture Chromatography, Polish, Formulation.
- Food — Mix, Pasteurise, Homogenise, Cool, Hold, Fill.
- Cosmetics — Oil Phase Heat, Water Phase Heat, Emulsify, Cool, Add Fragrance, Fill.
- Chemicals — Charge, React, Distil, Cool, Crystallise, Filter, Dry, Pack.
06Common mistakes
- Treating phases as operations — "Charge" alone is not an operation; it is a phase inside the Dispense operation.
- Operations without explicit material-state postcondition — genealogy fragments.
- IPC sampling points buried inside phases — sampling plan disconnected from recipe.
- Operation duration estimates not maintained — scheduling progressively diverges from reality.
- Operation naming inconsistent across recipes — cross-product analytics impossible.
- Operation-level deviations recorded at phase level — review-by-exception cannot summarise.
07How V5 Ultimate handles operations
Frequently asked questions
Q.Can an operation span more than one unit?+
No. Like its parent unit procedure, an operation is bound to a single unit. Material moving to a new unit is a transfer phase, ending one operation and beginning the next in the destination unit procedure.
Q.Is a sampling event an operation?+
Usually not — sampling is a phase attached to an operation boundary. The operation is the material-state change; sampling is the act of capturing material for testing.
Q.How granular should operations be?+
As granular as your process scientists describe the process. If a tech-transfer document says 'granulation, then drying, then milling', those are three operations. Do not split further unless the split corresponds to a material-state change.
Q.Should CIP be an operation?+
Often yes, particularly when CIP/SIP is a validated, multi-step cycle with its own IPCs (conductivity, temperature, hold times). Treating it as a unit procedure or operation gives it the genealogy and audit-trail footprint it warrants.
Q.How do operations affect parametric release?+
Parametric release works when operation-level CPPs and IPCs are within validated ranges and no operation-level deviations occurred. The operation is the smallest unit at which 'all in control' can be asserted; if every operation is clean, the batch is releasable by exception.
Primary sources
Further reading
Want to see how Operation could fit into your own records and workflows? Explore the related V5 pages or talk to our team about what applies to your operation.