Continuous Cleanroom Particle Monitoring
Fixed-point particle measurement at risk-assessed locations, reporting into a monitoring system to provide trends, alarm behaviour and retained evidence that environmental performance has been maintained. Monitoring provides ongoing evidence; it does not replace periodic classification.
Continuous monitoring scope and location strategy
Classification answers “what was the concentration at these locations, in this state, on this occasion”. Monitoring answers “has performance been maintained since”. The two use different instruments, different placement logic and produce different evidence.
Risk-based monitoring location strategy
Locations are selected through the monitoring plan, considering process risk, critical exposure points, transitions, airflow behaviour and the intended use of the space. The objective is not simply uniform geometric coverage.
- LocationsSelected by risk to product or process, and justified in the plan.
- Size channelsChosen to match what the plan needs to detect.
- Alarm limitsWith defined delays, escalation and acknowledgement behaviour.
- RecordsRetention period and integrity requirements set by the quality system.
Monitoring and formal classification
Classification requires a defined sampling plan, defined sample volumes and a stated occupancy state. A fixed sensor samples one point continuously; that is a different measurement with a different purpose, and it cannot be substituted for a classification result.
The reverse also holds: a portable classification counter used periodically is not by itself a monitoring system, because it provides no continuity of evidence between visits.
Governing references
ISO 14644-2Monitoring to provide evidence of continued cleanroom performance EU GMP Annex 1Operational environmental monitoring — pharmaceutical context onlyISO 14644-2 does not classify a cleanroom. Classification is the role of ISO 14644-1 — see Cleanroom Classification →
Continuous monitoring system architecture
Sensor interfaces and facility integration
How sensors report determines what the system can be built on. A serial multi-drop keeps cabling simple across many points; Ethernet suits integration with an existing facility network; an analogue output lets a sensor feed a PLC, data logger or building-automation system directly where no dedicated monitoring software is in scope.
- RS-485 serialMulti-drop across distributed points, Modbus communication.
- EthernetIntegration with a facility network or monitoring server.
- Analogue output4–20 mA into PLC, logger or building automation, where supported by the model.
Semiconductor critical-area contamination monitoring
In contamination-sensitive manufacturing, continuous monitoring is what turns a periodic classification result into an ongoing contamination-control capability. Sensors sit at the locations where an excursion would matter most, and report into the fab monitoring network.
Sensor sensitivity should follow the same logic as classification: the sensor must resolve the size the monitoring plan is concerned with.
Semiconductor classification & 0.1 µm →Pharmaceutical operational environmental monitoring
Current EU GMP Annex 1 distinguishes cleanroom qualification and requalification from ongoing operational environmental monitoring, and places both inside a documented contamination control strategy. Continuous particle monitoring belongs to the second of those.
What the monitoring programme must cover, at which grades, at what frequency and with what record integrity is determined by the facility, its contamination control strategy and the applicable regulation — not by the instrumentation.
Complementary environmental monitoring routes
Standards and regulatory applicability
| Reference | Edition / status | Role |
|---|---|---|
| ISO 14644-2 | 2015 (Edition 2) — Current published reference | Monitoring to provide evidence of cleanroom performance related to air cleanliness by particle concentration |
| EU GMP Annex 1 | 2022 revision — Current published revision | Operational environmental monitoring where the pharmaceutical context applies |
Scroll the table horizontally →
ISO 14644-2 does not classify the cleanroom. It addresses the monitoring plan used to provide ongoing evidence of performance related to airborne-particle concentration. Classification of air cleanliness is the role of ISO 14644-1, on the Cleanroom Classification page.
Remote particle sensing technologies
Specifications come from the product page. Particle-size options, flow and interface vary by model and variant — the product page carries the complete data.
3718-AFixed-point monitoring where the smaller channel pair is required.- 0.3 / 0.5 µm
- 28.3 L/min (1.0 CFM)
- External vacuum source
- RS-485 Modbus · 4–20 mA
3719-AFixed-point monitoring where the larger channel pair is required.- 0.5 / 5.0 µm
- 28.3 L/min (1.0 CFM)
- External vacuum source
- RS-485 Modbus · 4–20 mA
3720-06Built-in-pump remote particle sensing where no external vacuum line is available.- Built-in pump
- 28.3 L/min (1 CFM)
- Channels by configuration
- Ethernet · RS-485 · 4–20 mA
Continuous monitoring system configuration
Share the monitoring locations, the particle size and flow the plan requires, the interface the facility uses and the record and alarm behaviour the quality system expects.