Airflow Visualization (Smoke Study)

Airflow visualization (smoke study) is a practical, visual test to verify airflow patterns, room pressurization, laminar flow direction, and containment in cleanrooms, isolators, LAFs, transfer hatches, and critical production zones. PrimeGMP performs controlled smoke studies to demonstrate airflow directionality, identify dead-legs, assess containment integrity, and confirm that air movement matches design intent and regulatory expectations.

Objectives

• Verify airflow direction and pattern in at-rest and operational states
• Confirm pressure differentials and directionality between adjoining zones
• Identify short-circuiting, recirculation, and dead-air zones
• Validate unidirectional flow (where required) and containment in critical areas
• Support OQ / PQ of HVAC and aseptic zones with visual evidence

Scope

Smoke studies are performed for:

• Cleanrooms (ISO classifications) — at-rest & operational
• Laminar flow hoods / LAF cabinets / BSCs / isolators
• Transfer hatches, pass-throughs, and material/personnel airlocks
• Critical door opening tests and gowning areas
• Aseptic filling suites, vial washing, and sterile corridors

Methodology

1. Planning & Risk Review
   • Review URS, P&IDs, HVAC drawings, SOPs and critical zones.
   • Define test points, worst-case positions, and operational conditions.
2. Pre-checks
   • Verify calibration of pressure gauges, anemometers, and temperature/RH sensors.
   • Ensure personnel safety & non-contamination (non-residue smoke).
3. At-Rest Smoke Study
   • With systems running but no personnel/equipment operation, generate smoke at defined points (inlets, ceiling plenum, transfer hatches).
   • Observe and record directionality, leaks, and short-circuiting.
4. Operational Smoke Study
   • Repeat tests with typical personnel movement, doors opening, equipment running, and production load to capture realistic disturbances.
5. Localized / Point Tests
   • LAF/BSC smoke visualization to confirm unidirectional flow and absence of turbulence at work zone.
   • Transfer hatch and pass-through verification during door cycles.
6. Data Capture
   • High-resolution video & time-stamped photos.
   • Simultaneous logging of pressure differentials, air velocities, and environmental conditions.
   • Notes of personnel/equipment behaviour during tests.
7. Analysis & Remediation
   • Identify non-conformances (airflow reversal, recirculation, dead zones).
   • Recommend engineering or procedural corrective actions (balancing, deflectors, slot adjustments, SOP changes).

Instruments & Materials

• Non-toxic, non-residue smoke/toxic-free theatrical foggers or smoke pens (ISO/USP-acceptable)
• Hot-wire / vane anemometers for airflow velocity
• Differential pressure manometers (calibrated)
• Particle counter (optional, for correlation)
• Video camera and still photography (time-stamped)
• Environmental loggers for Temp/RH

Acceptance Criteria

• Airflow direction consistent with design intent (e.g., from cleaner → less clean)
• No sustained recirculation or contamination pathways into critical zones
• Unidirectional flow maintained within acceptable turbulence limits at the work zone
• Pressure differentials match defined setpoints within agreed tolerances
• Smoke dissipates or follows designed flows without infiltration into critical areas

(Exact acceptance values to be defined in protocol per facility URS / risk assessment and regulatory expectation.)

Deliverables

• Pre-test checklist and protocol (DQ/OQ addendum where applicable)
• Time-stamped video & photo evidence package (at-rest and operational)
• Smoke flow maps and annotated images showing flow direction & issues
• Measured pressure/velocity logs correlated with visual evidence
• Detailed observation log, root-cause analysis, and CAPA recommendations
• Final report with executive summary for audits and regulatory inspections

Standards & Guidance

• ISO 14644 (Cleanroom classification & testing context)
• EU GMP Annex 1 (Aseptic processing expectations)
• WHO Good Practices and relevant TRS documents
• Facility URS, risk assessment (ICH Q9) and internal SOPs

Safety & Limitations

• Use only non-residue, non-contaminating smoke sources approved for cleanroom use.
• Smoke studies visualize airflow behavior but do not replace microbiological or particle testing — they are complementary.
• Results are snapshot-based; repeat tests recommended where significant process changes occur.

Why PrimeGMP

• Experienced engineers and microbiologists conducting smoke visualization for sterile & non-sterile environments
• Calibrated instruments and audit-grade video documentation
• Actionable engineering and procedural remediation recommendations
• Seamless integration with HVAC OQ/PQ and facility qualification packages