Laminar Flow Hood Uses And Functions

November 3, 2021

Within the scientific, pharmaceutical and clinical industries, it is essential to have spaces that are free of bacteria or microorganisms that can contaminate the workspace. This is why laminar flow hoods are those tools that allow obtaining a sterile and safe area for any need that is required within a laboratory.

In professional performance and for many laboratory work it is necessary to protect the product from contamination, either from the environment or from personnel. When working with dangerous products or microorganisms, it is also necessary to protect the operator and the environment.

To achieve this, we have LAMINAR FLOW HOODS that allow us to protect the product that is made and BIOLOGICAL SAFETY CABINETS that allow us to protect the product, the personnel and the environment. The selection of equipment will depend on the material with which you work.

What is the Laminar Flow Hood

The laminar flow hood, also known as a laminar flow cabinet, is an instrument used to achieve contamination-free environments, since it manages to provide decontaminated air from particles down to 0.1 microns. Thus, the work area always remains clean and sterile; an environment that is essential, especially in laboratories, where they usually work with cell cultures, biological material, corrosive chemicals or infectious organisms.

This instrument can be used by students studying careers belonging to the Faculty of Engineering, such as Food, Environmental, Biomedical and Chemical Engineering, among others. It is advisable to use this machinery in all cases, since sometimes it works with corrosive and harmful substances for the human body or, sometimes, it is simply necessary to sterilize the environment to study effects of any kind.

Laminar Flow Hood Types

There are two models of hoods: the first has a vertical position and the second horizontal, and from this the location of the filter is determined, which can be placed in the upper or rear part of the work area.

  • Those with horizontal flow are those in which the HEPA filter is placed at the back of the hood, so the unidirectional air flow moves through horizontal parallel lines, that is, from the back of the equipment towards the operator.
  • Vertical flow hoods are those in which the HEPA filter is placed in the upper part of the hood, so the unidirectional air flow moves through vertical parallel lines. They have a transparent protective screen that covers the upper front part of it

Laminar Flow Hood Functions

All laminar flow hoods are delimited by stainless steel sheets. On the front it has tempered glass doors and on the top a fan that will provide air from the environment. The fan speed is regulated by means of a controller, in order to reach the adequate speed and pressure so that the flow in the work area is laminar. In this way, the air speed will be from 0.3 to 0.5 meters per second in a constant way in order to always have the surface swept.

When all the air that enters the work area is filtered through the HEPA filters, a unidirectional flow is produced, since the air moves through the work area with a uniform speed along parallel lines achieving a sweep or elimination of the particles present in it. Previously this movement was called laminar, for that reason the equipment was called laminar flow hoods, a name that is still used.

Laminar Flow Hood Applications

Applications for Laminar Flow Cabinets include plant tissue culture, media plate preparation, electronic material inspection, medical device assembly, and polymerase chain reaction experiments. Laminar flow hoods are commonly used to:

  • Prepare bacterial culture media.
  • Fill sterile products and antibiotics.
  • Mix food.
  • Non-pathogenic crops.
  • Prepare mixtures of intravenous solutions.

Biological Safety Cabinet

In cases where it is necessary to work with certain microorganisms, cytotoxic products or products that cause allergic reactions, biological safety cabinets should be used that are similar in design to vertical laminar flow hoods, but have the same filters at the air outlet. HEPA that retain contaminants, thus achieving the protection of the product, the operator and the environment.

Biological safety cabinets (GSBs) are designed to protect the worker, the laboratory environment and the work instruments, from being exposed to infectious aerosols and splashes that can be generated when handling materials that contain infectious agents such as primary cultures, control strains and clinical samples for diagnosis.

Aerosol particles less than 5 µm in diameter and droplets 5 to 100 µm in diameter are not visible to the naked eye. The laboratory worker generally does not realize when these particles are being generated so they can inhale them or cause cross contamination of the surface of work instruments.

When used properly, GSBs can effectively reduce laboratory-acquired infections and cross-contamination of cultures from exposure to aerosols. GSBs also protect the environment.

Considerations when working with these Hoods

  • These equipments must be placed in rooms, free from drafts, and with restricted access. Usually there is a previous changing room where the staff puts on the gown and other garments.
  • The personnel who will work in the hood must wear clean clothes. Long-sleeved gowns with closed cuffs, hats and shoe covers are recommended. Depending on the task to be carried out, the use of gloves (without powder) may be required.
    In other cases, the use of special sterile uniforms is required.
  • The unidirectional air flow can be disturbed by air currents caused by sudden movements made inside it, by walking quickly in front of it or by equipment that can produce them, for which it is recommended not to insert and remove your hands during the work and move them
    slowly inside.
Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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