Class I Bio-Hazard Safety Cabinet : Class I Bio-Hazard Safety Cabinet (formally known as type B3) provide personnel, product, and environment protection. Class I Cabinets differ in the proportion as 70% air is re-circulated within the cabinet through high efficiency particulate air (HEPA) filtration. These are designed as per ISO CLASS 100 as per ISO 14644-1. Velocity of airflow to the work zone creates an ultra-clean environment for product protection, where the remaining exhaust air is discharged out. 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 through 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 a HEPA filter.