Class II Type A2 Biological Safety Cabinet

What is the Class II Type A2 Biological Safety Cabinet?

A class II type A2 biosafety cabinet draws 70% of its air through HEPA filters and recirculates it, exhausting the remainder through a second filter, protecting both operator and culture for most cell and tissue work.

Overview

Room air enters through a front grille, is filtered and delivered as a sterile downflow curtain, then splits at the work surface so that about 70% recirculates to the supply filter and 30% leaves through the exhaust HEPA filter. Downflow velocity is typically 0.25–0.35 m/s and inflow about 0.5 m/s, creating an air barrier at the front opening. The work zone is usually 1.2–1.8 m wide with a stainless steel interior, a single-piece work tray and negative-pressure plenums that keep contaminated air away from the operator. Alarms warn of airflow faults, and some models add an electrical outlet panel, gas cock, vacuum port and a UV lamp. A2 cabinets can exhaust into the room or be ducted, and they are the standard choice for cell culture and sterile compounding.

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?

• Recirculating airflow with 70% recirculation and 30% HEPA-filtered exhaust
• Downflow velocity of about 0.25–0.35 m/s
• Stainless steel work zone with one-piece spill tray
• Negative-pressure plenums protecting the operator
• Airflow alarms with filter integrity test points
• Optional outlet panel, gas cock, vacuum port and UV lamp

What are the technical specifications?

A typical class ii type a2 biological safety cabinet configuration offers working width of 1.2–1.8 m (model dependent), 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, recirculation ratio of approx. 70% recirculated, 30% exhausted and interior material of 304 stainless steel. 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 A2 Biological Safety Cabinet is used in routine aseptic cell culture and subculture, primary cell and stem cell handling, media and reagent preparation and cell therapy product processing in closed systems. 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 A2 Biological Safety Cabinet?

Select a type A2 cabinet for most cell culture work where operator and product protection are both needed and recirculation is acceptable. Specify working width, airflow velocities, alarm set points, interior material and the service fittings required inside the work zone.

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.