Laminar Flow Hoods, A Guide to Buy Laminar Flow Hood

You are looking to buy a Laminar Flow Hood, Here are what you need to know:

1- Laminar flow Hood Applications:

Laminar Flow Hoods (Laminar Flow Cabinets) are widely used in research laboratories, semiconductor manufacturing, biotechnology, and other fields such as sterile working procedures in mushroom cultivation, IV preparation, tissue culturing, and data recovery applications that are very sensitive to airborne contamination.

Note: Most laminar flow workstations are not to protect operators and only protect samples from contamination. They must not be used for applications are hazardous to operators.

2- Laminar Flow Hood Function:

The air entering a laminar flow hood from room is filtered through high-efficiency particulate air (HEPA) or ultra-low particulate air (ULPA) filters to exclude air particulate & dust.

Unidirectional, or Laminar air flow is pushed from the filter surface downward or in horizontal direction to maintain sterile conditions under the hood. To avoid turbulence, work is normally done in the clean work zone, away from obstructions.

3- Laminar Flow Hood Classifications:

As in Clean rooms, Laminar flow hoods and clean benches are classified based on the number and size of particles tolerated per volume of air in the work zone. Along with the air cleanliness, air flow speed, and air flow patterns are important factors that need to be met.

Airborne Particulate Cleanliness Classes for Laminar Flow Hoods

Hood Class





Max. Number of Particles /m3 (/ft3)
≥ 0.1 µm ≥ 0.2 µm ≥ 0.3 µm ≥ 0.5 µm
ISO 3 Class 1 1,000 (35) 237 (7.5) 102 (3) 35 (1)
ISO 4 Class 10 10,000 (350) 2,370 (75) 1,020 (30) 352 (10)
ISO 5* Class 100* 100,000 (3,500) 23,700 (750) 10,200 (300) 3,520 (100)

*Most common class for clean bench is ISO 5 (Class 100)

5- Laminar Flow Hood Types:

As far as Airflow direction is concerned, Clean Benches come either in vertical or horizontal filtered laminar air flow design.

  • Horizontal Flow Clean Bench: Clean air moves from a filter located behind the work surface toward operator. Often used for clinical or pharmaceutical applications. Visit Cleatech® Horizontal Laminar Flow Hoods
  • Vertical Flow Clean Bench: Clean filtered air moves downward from the filter surface on the top to the work surface. Available in bench-top, free-standing, and portable design that meet cleanliness requirements of ISO4 & ISO5 . Visit Cleatech® Vertical Laminar Flow Hoods

Other Types of Laminar Flow Workstations:

  • Pharmacy Compounding Isolator: A laminar flow cabinet with the glove/ arm ports designed to provide a sterile positive pressure environment for the compounding of non-hazardous drugs and to meet the standards of USP <797> and <800>. HEPA filtered laminar air flow supply within both the work zone and antechamber area to ensure ISO class 5 conditions. See Cleatech® Compounding Aseptic Isolators
  • Laminar Flow Booth: Fixed or portable free-standing station with non-turbulent laminar airflow mostly in vertical flow direction. They are smaller than a mini cleanroom and taller than regular benchtop laminar flow hood. The work table can be placed under the particle-free stream of air isolated from the hood construction. So, they would be great choice for application sensitive to vibration.  Visit Cleatech® Free-standing Laminar Flow Stations
  • Mini Cleanroom: Create a contaminant-free walk-in environment for your critical work. Integrated fan/ HEPA filter modules are placed on the ceiling to provide class 1 up to class 10,000 clean-room. Usually constructed of the steel frame and soft vinyl wall / curtain strips.
  • Clean Air Storage Cabinet: They are storage cabinet that provide a positive pressurized clean environment for storing products that required clean conditions such as ISO 4 or ISO 5. As in standard cabinet they can be used with shelving (perforated) for optimum storage space. See Cleatech ® Laminar Flow Storage Cabinets
  • Laminar Flow Biosafety Cabinet: The regular LFHs protect only the product in the hood while the BSCs protect both the user and the product in the cabinet from hazardous contamination. Biological safety cabinets are available in several classes (I, II, and III) based on the protection level. Actually, BSCs are laminar flow hood with exhaust. They have HEPA filters at their air supply and exhaust points. Visit Biological Safety Cabinets

6- Laminar Flow Accessories:

  • UV-C germicidal lamp Laminar flow hoods may have a UV-C light to sterilize the interior and contents before usage to prevent contamination of experiment.
  • Ionizing bar controls electrostatic charge in flow hoods and clean benches and provides a continuous stream of static-neutralizing ions to protect sensitive materials against ESD.
  • Air velocity meter is used to monitor performance of an airflow system such as laminar flow hood. Some types come with audible and visual alarms.

7- Laminar Flow Performance Testing:

Performance Testing is required for certification, and maintenance of laminar flow units & clean benches to remain compliant with safety guidelines. Here are some of the common tests need to be performed:

  • Integrity Testing of HEPA filters
  • Particle Counting
  • Airflow Visualization
  • Sound Level Measurement
  • Fluorescent light testing

External Links:

Cleatech Laminar Flow Hoods & Clean Benches

Laminar Flow Hood for Sales

Laminar Flow Products