Cleanroom & Contamination Monitoring

ISO 21501-4 specifies how a light-scattering airborne particle counter is calibrated and verified: counting efficiency, size accuracy and resolution, sampling flow rate, false counts and related metrological performance. SafyrOPC is factory-calibrated to this standard and supplied with an individual certificate, which is what makes its counts traceable.

SafyrOPC provides ISO 21501-4-calibrated particle-count data that can support cleanroom classification and monitoring strategies, subject to the applicable sampling plan and validation requirements. Classification itself depends on the number of sampling locations, the sample volume per location and the statistical treatment defined by the standard, not on the counter alone.

SafyrOPC can support risk-based continuous monitoring strategies in ISO 5-8 cleanrooms and GMP Grades B, C and D, subject to the facility contamination-control strategy, sampling plan and validation requirements. Its role in a given installation has to be defined by that strategy.

No. For Grade A, Annex 1 requires continuous monitoring of ≥0.5 µm and ≥5 µm particles throughout the duration of critical operations, with a sample flow rate of at least 28 litres per minute. SafyrOPC samples at 2.83 L/min and is not positioned as the primary Grade A monitoring system. It is intended for Grades B, C and D and for extending coverage elsewhere in the facility.

Sensor SafyrOPC is the calibrated counting module, intended for integration into equipment, isolators, tools or a customer monitoring system. The SafyrOPC instrument packages that same module into a standalone monitoring point with its own enclosure, power, communication and mounting, ready to be deployed in a controlled area.

A higher flow samples a larger volume of air in a given time, which matters when the particle limit is low and few particles are expected. A lower flow allows a more compact and less costly monitoring point. The appropriate flow depends on the cleanroom class, the particle limit, the monitoring objective and the response time required — it is a design decision, not a universal ranking.

A particle counter only measures the air entering its inlet. Locations should therefore be selected according to airflow patterns, critical operations, equipment interfaces and risk to the product, and monitoring should take place during operations. Regulatory guidance is explicit that measurement should occur at the locations posing the most risk to exposed product.

A manifold connected to several sampling locations measures them sequentially. While the system samples one location, the others are not being measured, so a short excursion elsewhere can pass unrecorded. The size of that gap depends on the number of points and the cycle time of the specific configuration.

Remote sampling tubes delay detection and lose particles through settling, bends and impaction, and the loss is most pronounced for larger particles. ISO 14644-21 identifies tubing longer than about one metre as requiring assessment. Shortening the sampling path — by placing the counter close to the point — reduces that dependency.

The calibrated sensing module can be replaced on site, so a monitoring point returns to service with a freshly calibrated module instead of waiting for the complete instrument to come back from the laboratory.

Yes. Sensor SafyrOPC communicates over UART and Modbus, and the instrument offers wired and wireless options, so monitoring points can feed the facility data architecture alongside the parameters already collected.

PMDuct monitors the HVAC supply path, upstream of the controlled area, and can reveal changing particle conditions before the air reaches the room. It measures PM mass fractions and is not an ISO 21501-4 cleanroom particle counter: it complements room counters rather than contributing to classification.