Continuous Monitoring vs Periodic Certification: Are We Testing Too Little — or Too Much?

Certifications verify, monitoring protects — together, they keep cleanrooms in control

In the world of controlled environments — from aseptic compounding rooms to high-stakes pharmaceutical cleanrooms — a question is increasingly being asked: “Do we still need traditional periodic certifications if we’ve installed advanced continuous monitoring systems everywhere?”

Continuous monitoring is exciting. It beeps, it trends, it generates dashboards that almost make your cleanroom feel alive. But before we assume automated controls can run the show, it’s worth asking a more critical question: Can sensors truly replace the expertise, judgment, and nuanced testing that skilled certifiers provide?

Spoiler alert: not even close.

Periodic Certification: The Foundation of Compliance

Periodic certification is the cornerstone of controlled environment oversight. It is the definitive verification that your cleanroom functions as intended and meets regulatory requirements.

Typical periodic certification includes:

• Airborne particle counts (both viable and non-viable)

• Differential pressure verification between zones

• Airflow velocity mapping and laminarity checks

• HEPA/ULPA filter integrity testing

• Air changes per hour and recovery testing

  
  

Each assessment is a snapshot in time that provides proof the system meets design specifications.

Why periodic testing is irreplaceable:

1. Validation of system design: Continuous sensors track ongoing performance, but certification proves your system functions correctly under controlled challenge conditions.

2. Regulatory compliance: Health authorities, auditors, and accreditation bodies still rely on formal certification reports as documented evidence.

3. Capturing anomalies: Certain deviations only appear under controlled stress conditions — for example, smoke studies or filter integrity challenges. Sensors alone may miss these.

   
   

Think of certification as the “cleanroom’s annual physical.” Sensors track trends, but certification validates the core health of the system. One without the other is incomplete.

Continuous Monitoring: The Real-Time Guardian

Continuous monitoring uses permanently installed sensors to provide real-time oversight of:

• Airborne particle counts (≥0.5 µm and larger)

• Differential pressures

• Temperature and humidity

• Airflow trends

  
  

Continuous monitoring allows facilities to:

• Detect excursions in real time

• Respond to deviations immediately, reducing contamination risks

• Collect trend data to inform maintenance schedules and predictive interventions

  
  

However, while continuous monitoring is powerful, it comes with limitations:

• Sensor placement matters: A poorly positioned sensor may give a false sense of security.

• Data interpretation is critical: Raw numbers need expert analysis; trends don’t always indicate true control issues.

• It doesn’t challenge the system: Sensors observe; they don’t stress the cleanroom under operational or design testing conditions.

  
  

In other words, continuous monitoring is a guardian — vigilant and observant — but it cannot replace the structured challenge and analysis that certification provides.

Why Both Are Essential

The question isn’t whether to choose one over the other; it’s how to integrate them effectively.

• Periodic certification provides structured, regulated verification that the cleanroom and its systems perform as intended.

• Continuous monitoring provides ongoing surveillance, allowing for rapid intervention and trend analysis.

  
  

When used together, they form a multi-layered defense against contamination and non-compliance: certifications validate the system’s baseline, while continuous monitoring ensures the system stays in control every day between certifications.

A Technical Perspective

From a technical standpoint, certifications test critical performance metrics under controlled conditions:

• Airflow patterns: Smoke studies during certification can reveal areas where the air may be swirling or moving in unintended directions, which standard sensors might not detect.

• HEPA filter integrity: Challenge tests verify filter performance; sensors can’t confirm filter integrity, only particle counts downstream.

• Room recovery: Room recovery testing ensures that the cleanroom can return to ISO grade specifications after a disturbance, which is impossible to measure with static sensors alone.

  
  

Continuous monitoring, however, excels in detecting operational excursions and providing actionable data for facility operations. Combining both approaches allows facilities to meet expectations while maintaining day-to-day assurance of control.

Lighthearted Analogy

Imagine your cleanroom as a superhero duo. Periodic certification is Batman — methodical, precise, and a trusted authority. Continuous monitoring is Robin — fast, observant, and always catching the small things Batman might miss. You wouldn’t want Robin without Batman, or Batman without Robin. Each has a role, but one ensures strategic compliance, while the other ensures operational vigilance.

The Bottom Line

Automated controls and continuous monitoring are transforming cleanroom management, but they cannot replace skilled certifiers and structured periodic testing. Certifications remain the bedrock of regulatory compliance, system validation, and operational integrity. Continuous monitoring complements certification, providing the real-time data that facilities need to stay in control between scheduled verifications.

The future is integration, not replacement. The best controlled environments are those that combine the rigor of periodic certification with the insights of continuous monitoring — and a little superhero teamwork doesn’t hurt either.