Smoke Tests
What is a Smoke Test?
A smoke study or test is an airflow visualisation technique used in controlled-contamination environments, such as cleanrooms, fume hoods, isolators and other pharmaceutical systems. The purpose is the make the airflows visible in order to determine their direction and stability, preventing turbulence, recirculation or deviations which could compromise the sterility of the products.
Smoke Tests
How Does It Work?
A smoke generator, or fogger, produces a visible smoke trace from purified water (WFI, Water for Injection), which is released into the critical points of the system. The cloud of particles follows the air flows and makes any anomalies or interference immediately visible. The video footage allows these behaviours to be analysed in order to assess the effectiveness of the ventilation systems and the security of the sterile process.
Smoke Tests
What Is It Used for?
Smoke Studies play a key role in validation and maintenance of systems:
- They confirm the correct design of the filtration and ventilation systems
- They highlight potential risks of cross-contamination
- They support the certification of environments and equipment (cleanrooms, fume hoods, isolators)
- They provide evidence required by international standards and GMP guidelines, in particular the revision of Annex 1 (2022).
Smoke Tests
Smoke Test Phases
Phase 1
As Built
Inspection of the conditions of the system when installed but not yet started up.
Phase 2
At Rest
Analysis of the air flows with machinery active but at rest.
Phase 3
Dynamic at rest
Analysis of the system in operation, but with operators not present
Phase 4
In operation
Analysis of the air flows with operators present and working on the production line
Smoke Tests
Fields of Application
All classified environments require visual verification of air flows in order to ensure compliance with the operational conditions required by standards and regulations, and to guarantee safe and reproducible processes.
Cleanrooms
Isolators
RABS
Horizontal LAF hoods
Vertical LAF hoods
Radiopharmaceuticals
Biosafety cabinets
Class transitions
