USP <797> Smoke Studies and Airflow Visualization
USP <797> establishes minimum standards for compounded sterile preparations. Airflow visualization can support engineering and certification work, but the chapter does not turn a specific fogger into an automatic compliance solution.
Use the chapter as the authority
The current official USP chapter and the facility’s certification procedures should control. The study should be integrated with the cleanroom, PEC, pressure, environmental monitoring and personnel program rather than treated as a standalone video exercise.
Common visualization targets
- Primary engineering controls and critical work zones
- Airflow across pass-throughs and doors
- Pressure-boundary behavior during entry and exit
- Material transfer and staging practices
- Operator hand and arm movements
- Interaction between room supply, return and local devices
- Changes after equipment or layout modification
Select output to fit the space
A very large LN₂ system may be unnecessary for a localized PEC study and can increase condensation and visibility-management challenges. Conversely, a small ultrasonic system may not provide the persistence needed for room-scale pathways. The method should choose the least disruptive technology that creates clear evidence.
Build a defensible fogger requirement
Send Applied Physics the room, process, utilities, documentation and safety constraints—not just a model number.