Regulatory guidace on Smoke study

Air pattern or “smoke” studies demonstrating laminarity and sweeping action over and away from the product under dynamic conditions should be conducted.  

The studies should be well-documented with written conclusions.  Videotape or other recording mechanisms have been found to be useful in assessing airflow initially as well as facilitating evaluation of subsequent equipment configuration changes.  However, even successfully qualified systems can be compromised by poor personnel, operational, or maintenance practices.

Smoke studies and multi-location particulate data are vital when performing qualification studies to assess whether proper particulate control dynamics have been achieved throughout the critical area. 

Personnel should minimize interventions into the critical zones. Such interventions can adversely disrupt the unidirectional   and should therefore be designed to minimize both the extent and frequency of occurrence.  

Equipment should not obstruct airflow and, in critical areas, its design should not disturb unidirectional airflow.

Rapid movements can create unacceptable turbulence in a critical area. Such movements disrupt the unidirectional airflow, presenting a challenge beyond intended cleanroom design and control parameters. The principle of slow, careful movement should be followed throughout the cleanroom.

Keep the entire body out of the path of unidirectional airflow Unidirectional airflow design is used to protect sterile equipment surfaces, container closures, and product. Disruption of the path of unidirectional flow air in the critical area can pose a risk to product sterility.

Manufacturers should be aware of a device's air monitoring capabilities, and the air sampler should be evaluated for its suitability for use in an aseptic environment based on collection efficiency, cleanability, ability to be sterilized, and disruption of unidirectional airflow.

Exposure conditions should preclude desiccation (e.g., caused by lengthy sampling periods and/or high airflows), which inhibits recovery of microorganisms.

Evaluation methodology:  

• Studies demonstrating laminarity over the product path 
• Sweeping action away from the product path
• Activity/intervention performed as per procedure
• Any Turbulence observed in smoke flow
• Airflow is unidirectional 
• Airflow from supply and evacuate through return
• Clip demonstrate the complete interventions
• Density Smoke flow
• Continues smoke flow
• Visibility of intervention

If in case poor visibility mentioned the reasons (i.e Reflection / less lighting/denser smoke)
Result shall be reported as Yes or No and in some cases rating can be done as Very good "+++", Good "++", Improvement req. "+" and Poor "-"