Compare Cleanroom Operating Scenarios
Use this guide for an early comparison of cleanroom operating assumptions. The Semiconductor Operations workspace provides a discrete-event simulation (DES) view for comparing how particle generation, fan filter unit (FFU) count, door activity, gowning protocol, and study duration affect scenario-level results.
Pair the comparison with current particle, pressure, temperature, humidity, filter, and work-order evidence before using it in an operating review.
Workflow
Prerequisites
| Requirement | Why it matters |
|---|---|
| Cleanroom identity | Connects the scenario to the correct room, target class, and equipment |
| Current operating data | Provides particle, pressure, temperature, humidity, and filter context |
| Scenario owner | Confirms assumptions and the comparison question |
| Quality or facilities reviewer | Reviews whether the output can support the intended decision |
Configure a scenario
- Open Semiconductor Operations > Cleanroom Simulation.
- Select the cleanroom.
- Enter the particle generation rate used for the comparison.
- Enter the active FFU count.
- Set the expected door-opening frequency.
- Select the gowning-protocol state.
- Set the study duration.
- Record the reason for the scenario and the baseline it will be compared with.
- Choose Run Simulation.
Change one operating assumption at a time when the goal is to understand its effect. Use a named scenario package when several coordinated changes must be evaluated together.
Review the result
| Result | Review question |
|---|---|
| Average particle count | How does the scenario compare with the baseline and measured range? |
| Recovery time | How quickly does the model return toward its steady condition after door activity? |
| Achieved ISO class | Which modeled class band does the scenario reach under the selected assumptions? |
| Estimated energy | How does the FFU and operating-duration assumption change the scenario estimate? |
| Particle timeline | When do disturbances occur and how stable is recovery? |
| Air-change comparison | How does modeled particle concentration change across the compared air-change range? |
Traceable simulation evidence includes the cleanroom, scene, inputs, engine or model identity, run time, output, and reviewer. Results without that record remain a draft comparison.
Connect the result to operations
Compare the modeled result with:
- measured particle readings by size and sampling point;
- pressure-cascade status and door events;
- temperature and humidity trends;
- FFU assignment and filter condition;
- maintenance or work-order history;
- the latest ISO 14644 assessment record.
Record whether the scenario supports further measurement, an engineering study, a maintenance check, or a controlled operating trial.
Failure handling
| Problem | Response |
|---|---|
| Cleanroom or target class is unclear | Correct the room identity and target class before running the comparison. |
| Current particle or pressure evidence is stale | Refresh the operating data and record the measurement window. |
| Scenario inputs mix several unrelated changes | Create separate scenarios or document the coordinated change package. |
| The result has no model or run identity | Keep it as a draft and rerun through the traceable workflow. |
| Modeled trend conflicts with current measurements | Review assumptions with facilities and quality owners, then collect additional evidence or run a controlled study. |
Validation checklist
- Cleanroom and target class are correct.
- Units and duration are recorded.
- Baseline and changed assumptions are visible.
- Current measurements are attached to the review.
- The result has a traceable model or engine identity.
- Facilities and quality owners reviewed the proposed next step.