| Particulars |
Down Flow Booths |
High Containment Screens |
Restricted Barrier Access Systems (RABS) |
Barrier Isolators |
| Flow direction |
Unidirectional flow through ceiling HEPA |
NA |
Flow through clean room air circulation system or dedicated air filtration and conditioning system |
Uncompromised continuous flow through supply and return HEPA of dedicated air filtration and conditioning system |
| OEL levels of material handled |
Highest |
High |
Moderate |
Least |
| Health Hazard level |
Mild |
Moderate |
High |
Severe |
| Level of Isolation |
Least |
Moderate |
High |
Highest |
| Level of Automation |
Least |
NA |
High |
Highest |
| Application |
Effective protection when handling dusty material. |
Effective way of boasting down flow booth capabilities. |
Physical barrier between operators and production areas but barrier is limited. |
Uncompromised continuous isolation of its interior and external environment, including surrounding clean room and personnel. |
| Air flow carries the material away from the breathing zone of the operator into the low exhaust grill. |
Effective solution for air suits due to operational constraints. |
System’s interior atmosphere can be controlled however pressure control is limited. |
Effective pressure control in the interior of the system. |
| Classification NA: Not Applicable HEPA: High Efficiency Particulate Filter |
Recirculatory Booths Once Through Booths |
NA |
Passive Open RABS Active Open RABS Passive Closed RABS Active Closed RABS |
Positive Isolator; Negative Isolator |
