Class II Type B2 Biological Safety Cabinet

What is the Class II Type B2 Biological Safety Cabinet?

A class II type B2 biosafety cabinet passes all of its air through HEPA filters and exhausts it outdoors, so no air is recirculated. It is used where volatile chemicals, radionuclides or hazardous aerosols must be fully removed.

Overview

The cabinet draws room air and its own filtered supply air through the work zone and discharges everything through an exhaust HEPA filter to an external duct, maintaining a hard-ducted 100% exhaust configuration. Because nothing recirculates, chemical vapours and radioactive aerosols cannot accumulate in the plenums or filters, which makes the type suitable for work with volatile solvents, tracer radionuclides and cytotoxic drugs handled alongside cells. Airflow balance is more critical than in type A2 cabinets, and installation requires a dedicated exhaust system with specified static pressure and a monitoring device. Downflow and inflow velocities are similar to type A2, and certification procedures follow EN 12469 or NSF/ANSI 49 as for other class II cabinets.

How does it work?

Sterile work depends on supplying particle-free air and preventing entry of contaminants from the room. Room air is drawn through a HEPA filter that removes 99.99% of particles at 0.3 µm, and the filtered air flows in a laminar stream over the work surface. In a clean bench, air moves horizontally or vertically across the surface and out toward the operator, protecting the sample only. In a class II biological safety cabinet, air enters a front grille, passes through the supply filter to create a sterile downflow curtain, and is then split so that part recirculates and part is exhausted through a second HEPA filter, protecting both product and operator. A front air barrier prevents room air from entering the work zone when arms reach in, and airflow velocities are designed to balance containment against the risk of disturbing cultures.

What are the key features?

• 100% exhaust through HEPA filters with no recirculation
• Hard-ducted exhaust to an external blower system
• Suitable for volatile solvents and tracer radionuclides
• Downflow and inflow velocities matched to class II requirements
• Exhaust airflow monitoring with alarm
• Stainless steel interior with decontamination access points

What are the technical specifications?

A typical class ii type b2 biological safety cabinet configuration offers working width of 1.2–1.8 m, exhaust of 100% hard-ducted to external blower, downflow velocity of approx. 0.25–0.35 m/s, inflow velocity of approx. 0.5 m/s, filtration of HEPA, 99.99% at 0.3 µm, supply and exhaust and duct static pressure of as specified, typically 250–500 Pa. Values are indicative of the product class; the exact figures for each configuration are confirmed on the quotation and the calibration documents supplied with the instrument.

Which applications is it used for?

The Class II Type B2 Biological Safety Cabinet is used in cell work with volatile solvents or fixatives, cytotoxic drug handling with cell cultures, radionuclide tracer experiments in cells and cell processing under full containment. Across the wider Cell Culture Hoods class, laboratories also deploy it for aseptic cell culture and subculture, primary cell and stem cell handling and media preparation and bottle filling.

Which standards and certifications apply?

Relevant standards and methods include EN 12469, NSF/ANSI 49, ISO 14644-1, IEC 61010-1, IEC 61326-1 and USP <1046>. Certification candidates for this model are CE, NSF/ANSI 49 certification, EN 12469 certification and ISO 9001 manufacturing; each is to be confirmed for the specific configuration before shipment, and certificates are supplied only where they have been issued.

A new or relocated cabinet must be certified after installation and yearly thereafter, with filter integrity, downflow velocity, inflow velocity and airflow visualisation recorded against EN 12469 or NSF/ANSI 49. Avoid placing the cabinet near doors, windows, air supply diffusers or high-traffic routes, because draughts disturb the air barrier. Clean the work surface before and after use with 70% ethanol or a compatible disinfectant, and run the blower for several minutes before starting work. Do not block the front or rear grilles with equipment, since that alters airflow and can break containment. UV lamps are a supplement, not a substitute, for cleaning, and should be replaced when intensity falls below specification. Record certification, cleaning and maintenance in a log for audit purposes.

How do I select the right Class II Type B2 Biological Safety Cabinet?

Select a type B2 cabinet only when volatile chemicals, radionuclides or hazardous aerosols must be removed completely, since it requires an external exhaust system. Specify exhaust static pressure, blower capacity, duct routing, monitoring and alarm features and the containment level required.

How does it compare with other Cell Culture Hoods variants?

Decide first whether the operator needs protection. Any work with human or animal cells, infectious material or genetically modified organisms requires a class II cabinet, and a type A2 model covers most cell culture needs when recirculating exhaust is acceptable. Type B2 cabinets exhaust all air to the outside and are used with volatile chemicals or radionuclides that must not recirculate. Clean benches are appropriate only for non-hazardous cultures where sample protection alone is sufficient. Then check working dimensions, airflow velocities and alarms, filter integrity test points, interior material, UV lamp, and whether an electrical outlet panel and gas or vacuum service are needed inside the work zone. Confirm that the cabinet will be certified after installation in your laboratory and that the annual certification service is available locally.