A laminar flow hood, also called a laminar flow cabinet, is a laboratory equipment used to provide a contamination-free working environment for the workers. It is mainly found in the microbiology labs to deal with media and cultures.

This hood contains filters to capture the particles like dust or microbes to protect the research material.

Laminar Flow Hood Vs Biological Safety Cabinet

Both laminar flow hood and biology safety cabinets are structurally alike, but these are not the same. Laminar flow hood only provides a sterile environment to the product under research, and there is no personnel protection as the contaminated air can be drawn towards the worker.

Laminar Flow Hood vs. Biological Safety Cabinet diagram image
Diagram 1: Difference between Laminar Flow Hood and Biological Safety Cabinet

On the other hand, biology safety cabinets protect they also ensure both product and worker and environmental protection.

Parts of Laminar Flow Hood

A laminar flow hood consists of the following parts:

Stainless steel Cabinet

The whole chamber is stainless steel with no joints where bacterial spores or dust particle scan trap. Stainless steel prevents the cabinet from rusting. A laminar flow of air is created inside the cabinet. There is a glass screen on the front side that can be of two types.

Slidable Glass Shield

You can open it entirely, but it is recommended to open it half to protect the worker.

Glass Shield with Two Openings

This type of glass shield has two openings wide enough to put the worker’s hand in the chamber. Sterile your hand and working material with alcohol before entering them into the chamber.

Filters and Fan

There are one fan and two filters present in the laminar flow hood

Pre-filter or filter pad or HEPA (High-Efficiency Particulate Air) filter

The air first passes through the filter pad, which traps the significant contaminant. The fan sucks that air which is then passed through the HEPA filters. HEPA filters remove all the microbes providing sterile air flowing in the workstation.

UV Lamp

Ultraviolet rays have germicidal effects that sterile the chamber because of their germicidal effects. The UV rays can be harmful if they contact the human skin and can cause skin cancer. Turn the UV lamp on 15 minutes before starting your work.

Fluorescent lamp

A fluorescent lamp lit up the cabinet’s interior to carry out the work smoothly.

biosafety cabinet diagram labelled image
Image 2: Biosafety cabinet diagram labelled image

Working Principle of Laminar Flow Hood

  • It works on the principle of the laminar flow of the air. The air passes from the pre-filter through fans to the HEPA filters streamlined. This filtration system completely sterile all the air that flows into the chamber. The speed of air in the hood is always 0.5m/s
  • Procedure and tips for using Laminar Flow Hood
  • Remove all the trash and unnecessary items from the cabinet.
  • Keep the glass door window closed and turn on the UV lamp for 15 minutes.
  • After turning off the UV lamp, wait for 5-10 minutes. 
  • Turn the airflow on. After five minutes, open the glass window, turn the lamp on, and start working.
  • After completion, could you turn it off?
  • You can also use the alcohol to disinfect all the equipment and your hands.
  • These cabinets should be certified at least once a year or whenever moved from one place to another to ensure their working up to the required level.
laminar air flow working principle diagram with labeling
Image 3: Laminar flow working principle diagram

Types of Laminar Flow Hood

Laminar flow cabinets can be differentiated based on the direction of the air through them. They are of two types.

  1. Vertical Laminar Flow Hood

The air flows from top to the bottom of the chamber instead of blown directly toward the pace of the worker. There are holes in the base of the workstation to remove that air. It is much safer and more operatable.

  1. Horizontal Laminar Flow Hood

In this type of laminar flow hood, the air flows from the back of the chamber to the fronts that are towards the face of the worker. This type of air low endangers the worker and reduces the credibility of the equipment.

Types of Laminar Flow Hood vertical laminar flow hood and horizontal laminar Flow hood image
Image 4: Types of Laminar Flow Hood vertical laminar flow hood and horizontal laminar Flow hood image

Uses of Laminar Flow Hood

  • The contamination-free environment inside the laminar flow hood makes it useful for laboratories and industrial scale. Some of its uses are.
  • This hood is used in the tissue culture techniques
  • Virus inoculation in chick embryos or other mediums is carried out in the laminar flow hood.
  • It is widely used in media preparation and sterilization technique
  • Pharmaceutical companies use them for manufacturing germ-free drugs
  • Specific devices and equipment are operated inside the laminar flow hood.


  • Protect your skin from the direct contact of ultraviolet rays
  • Wear gloves and lab coat while operating laminar flow hood
  • Keep the glass window closed when the UV lamp is turned on
  • Sterile equipment before and after using them in the laminar flow hood.
  • Keep the glass window close when you are not running the hood.

Frequently Asked Questions

Q1. What is the use of a laminar flow hood?

A laminar flow filters the air and traps dust particles and microbes for providing a sterile working environment in the stainless-steel cabinet.

Q2. Why is a UV lamp used in the laminar flow hood?

It is used because of its germicidal effects to sterile the cabinet’s interior.

Q3. Why is it necessary to turn the UV lamp on before working?

UV radiations are harmful to human contact and can cause skin cancer. So, turn the lamp on for fifteen minutes, then wait for a further five minutes before opening the chamber and start working.

Q4. What is the difference between a laminar flow hood and a biology safety cabinet?

A laminar flow hood does not provide protection to the worker while the biology safety cabinets do so.


  1. Culture of Animal Cells; A manual of basic technique fifth edition by R. Ian Freshney

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