What is a Laminar flow hood?

Laminar Flow Hood

A laminar flow hood, also known as a laminar flow cabinet or laminar flow chamber, refers to an enclosure that uses a fan is forcing air through a HEPA or ULPA filter and thereby providing a uniform HEPA or ULPA filtered clean air free of particles even as small as 0.1 Microns, across the work or lab area. They help provide a well-filtered and uncontaminated airflow in the work area, thereby helping in the protection of lab samples from getting contaminated by airborne particles.

Laminar Flow hoods have several applications, mainly where clean air and a sterile and uncontaminated environment are required. Laminar Flow Hoods generally find their application in the medical and research laboratories for non-hazardous sterile pharma compounding, the assemblage of microelectronics and optics, cell culture, cultivation of mushrooms, etc. This equipment is primarily prismatic in shape.

Types of Laminar Flow Hoods

Commonly, there are two types of designs of Laminar flow hoods available that i.e.

 1. Vertical Laminar Flow Hood: In Vertical laminar flow hood designs, air flows down from the filter positioned above the work area. The air enters from above to the HEPA filter, and only pure and filtered air is allowed to flow through this and come inside the lab work area. They are designed to save floor space and are also accessible in setting up. 

 2. Horizontal Laminar Flow Hood: Horizontal Laminar Flow Hoods design helps direct the airflow parallel to the work surface, thereby leading to less turbulence. They also allow sterile material on the work surface to be easily positioned close to the filter face.

Both of these are available in explosion-proof configurations to be used in hazardous areas and the risk of ignition due to the existence of flammable substances and materials. They also can be configured into free-standing laminal flow hoods with vibration isolated tables for delicate operations.

In this article, we will primarily focus on Horizontal Laminar Flow Hoods.

Horizontal Laminar Flow Hood

In Horizontal Laminar Flow Hood, the room air generally enters the filter system behind the HEPA filter. The filtered air free from any particles is pushed and forced back parallel to the work surface. The Horizontal Flow system requires an additional depth for accommodating a rear-mounted filter or fan unit having an additional rear clearance to allow and direct the air into the system. Thus, it requires a deeper bench and comparatively more space of floor than vertical laminar flow hood.

The ambient air containing particles is drawn inside the filter unit and then passes through the filter. It is then directed by the blower towards HEPA or ULPA filters in a horizontal way across the work or lab area and thereby providing a clean, filtered, and particle-free air for the assemblage of microelectronic, tissue, and cell culture, sterile pharmaceutical compounding, mushroom cultivation, and other such applications.

Pros and Cons of Horizontal Laminar Flow Hoods

It is undeniable that even the greatest things in the world have some flaws in them. Here are some of the pros and cons of using Horizontal Laminar Flow Hoods:


  • The laminar airflow in the case of Horizontal Laminar flow hoods is generally parallel to the work surface. It thereby successfully eliminates the kind of turbulence that affects the Vertical airflow of Vertical Laminar flow Hoods, which strike just perpendicular to the work surface.
  • Horizontal Laminar Flow Hoods are easier in positioning and staggering the sterile equipment and material on the work surface closer to the filter face.


  • Servicing horizontal laminar flow hoods or changing their filters generally requires complete repositioning the hood for rear access.
  • If there are ample samples, they may obstruct the laminar airflow, resulting in contamination of downstream samples.
  • Usage of horizontal laminar flow hoods without sash can blow fumes, powders, or other contaminants right on the operator’s face.


Cleantech Cleanroom and Laboratory Solution can be a place to look for such Laminar Flow Hoods as it is clear from the abovementioned facts that such Laminal flow hoods play an essential role in the provision of filtered, clean, and particle-free airflow across workplaces and have a wide variety of applications in laboratory, pharmaceutical, culturing and assembly sectors.