Cleanroom Design
Room Classification
Cleanrooms are designed to maintain positive pressure, preventing contaminated air from entering critical process areas. Filtered air must always flow from the cleanest environment toward the less clean surrounding areas.
A differential pressure of approximately 7.5–12.5 Pa is commonly maintained between adjacent rooms. In Grade A isolator systems, internal pressures are typically around 25 Pa against the surrounding Grade C or D background environment.
Laminar and Turbulent Air Flow
ISO 5 environments rely on unidirectional (laminar) airflow. Filtered air is supplied uniformly in parallel streams, typically vertically, at around 0.45 m/s (±20%).
ISO 6 and higher classifications usually operate with turbulent airflow concepts where direction and velocity are less strictly controlled.
The major advantage of laminar airflow is the prevention of dead zones and contamination pockets inside critical process areas.
What is the advantage of ISO 8 (Isolator) compared to ISO 7 (RABS)?
Lower running costs
- Gowning is cheaper, less time consuming and overall operator comfort is significantly improved.
- Reduced air exchange rates lower energy consumption and HVAC operating costs tremendously.
