What is a flow cabinet?

A flow cabinet is a laboratory enclosure that provides protection against contamination through a filtered airflow. Every flow cabinet uses HEPA filtration to retain particles and micro-organisms. Depending on the type, a flow cabinet protects your product, your staff, or both.

How does a flow cabinet work?

Airflow and filtration depend on the cabinet type. A clean bench uses filtered air for product protection. A Class I safety cabinet protects the operator and environment, but not the product. A Class II safety cabinet combines inward airflow at the front opening with filtered downflow. Correct use and a suitable installation are essential.

What is the difference between a flow cabinet and a laminar flow cabinet?

Flow cabinet is the umbrella term for all cabinets with a filtered airflow. A laminar flow cabinet is the type that protects only the product, also called a LAF cabinet or clean bench. In practice, both terms are often used interchangeably.

What is the difference between Class I, Class II, and Class III?

A Class I safety cabinet protects the operator and the environment, but not the product. A Class II biosafety cabinet additionally protects the product through a downward, filtered airflow. A Class III safety cabinet has a fully enclosed workspace with glove ports. Its suitability for a process must be assessed separately. A laminar flow cabinet (clean bench) protects the product only and falls outside this system.

What is the difference between Class II type A2 and B2?

Type A2 recirculates part of the HEPA-filtered air. Type B2 exhausts all air through a purpose-designed external exhaust system, without recirculation. B2 is not automatically required for every procedure involving cytotoxic or volatile substances. The appropriate cabinet depends on the process risk assessment and the manufacturer’s installation and operating requirements.

What do the Class II type designations mean?

A1, A2, B1 and B2 are type designations from NSF/ANSI 49. They describe different airflow and containment arrangements. They are not interchangeable with the Class II designation used in EN 12469. Check the exact model, applicable certification and exhaust requirements rather than selecting a cabinet by the class name alone.

What is the difference between crossflow and downflow?

A crossflow cabinet has a horizontal airflow from back to front. A downflow cabinet has a vertical airflow from top to bottom. The appropriate airflow direction depends on the workspace layout and process. Both clean-bench designs provide product protection only.

Which standards apply to a biological safety cabinet?

EN 12469 describes performance requirements for microbiological safety cabinets. DIN 12980 concerns safety cabinets for handling cytotoxic substances. A laminar flow cabinet intended only for product protection does not automatically meet the same safety requirements. Applicable standards, test results and certification must be checked for each model and configuration.

How often should a flow cabinet be serviced and validated?

Set the maintenance and validation interval from the manufacturer requirements, risk assessment and applicable quality requirements. The tests depend on the cabinet type and application. After relocation, filter replacement or work that may affect airflow performance, assess what requalification is required.

How long does a HEPA filter in a flow cabinet last?

There is no fixed service life for every HEPA filter. Replacement depends on factors such as loading, filter integrity, airflow performance and manufacturer requirements. Have its condition assessed during maintenance and validation. Calendar age alone is not a replacement criterion.

Which brands of flow cabinet does Poly Temp supply?

We are an official dealer of Thermo Scientific for crossflow cabinets. We also supply downflow cabinets and n-Safe safety cabinets from Nordic Labtech. In addition, our engineers service all other brands, including Telstar, Esco, Berner, and Lamsystems.

Flow Cabinets

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Flow cabinets differ in the protection they provide. A laminar flow cabinet or clean bench protects the product. Depending on its class and design, a biological safety cabinet also protects the operator and environment. We supply models from Thermo Scientific and Nordic Labtech. The application, risk assessment and installation determine the appropriate cabinet and standards.

For a complete selection guide, see our flow cabinets landing page.