Recommended for Product, Personnel & Environmental protection Class II Cabinets differ in the proportion of air re-circulated within the cabinet; velocity of airflow to the work zone; where the exhausted air is discharged. Air barrier at the work opening and the contaminated air plenum is under positive pressure. An air barrier between the operator and the work zone is maintained by a flow of room air into a full width grille in the work opening. The barrier air mixes with the laminar flow air in a sump underneath the work surface, and is exhausted to the outside environment through duct via a HEPA
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