Laminar Flow Hood/Cabinet: Definition, Parts, Principle, Types, Uses (2023)

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A laminar flow hood/cabinet is an enclosed workstation used to create a contamination-free work environment by using filters to capture any particles entering the cabinet.

  • These cabinets are designed to protect work from the environment and are very useful for the aseptic distribution of certainmediajpour the plate.
  • Laminar flow booths are similar to biosafety booths, with the only difference being that in laminar flow booths, the outflow air is directed towards the user's face.
  • In a biosafety cabinet both the sample and the user are protected, while in the laminar flow cabinet only the sample and not the user is protected.
Laminar Flow Hood/Cabinet: Definition, Parts, Principle, Types, Uses (1)

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Table of Contents

(Video) What is Laminar Airflow Chamber? Definition, Principle, Parts and Types

Components/parts of the laminar flow hood

A laminar flow workbench consists of the following parts:

1. Cabinet

  • The cabinet is made of stainless steel with little or no gaps or joints to prevent spores from accumulating.
  • The housing isolates the internal environment created within the laminar flow and protects it from the external environment.
  • The front of the case features a glass shield that opens fully in some laminated cases or has two openings in some to allow the user's hands to enter the case.

2. Workplace

  • Inside the cabinet there is a flat work station for all processes to be carried out.
  • Culture plates, burners and handles are placed at the work station where the operation takes place.
  • The countertop is also made of stainless steel to prevent rusting.

3. Filter mat/pre-filter

  • At the top of the cabinet is a filter mat through which air is drawn into the cabinet.
  • The filter pad prevents dust particles and some microbes from entering the working environment inside the case.

4. Fan/Blower

  • A fan is located under the filter pad, which sucks in air and moves it through the housing.
  • The fan also allows air to flow into the HEPA Sp filter, so any remaining microbes are caught as they pass through the filter.

5. UV-Lampe

  • Some laminar flow hoods may have a germicidal UV lamp that sterilizes the cabinet interior and contents prior to operation.
  • The UV lamp must be turned on 15 minutes before the operation to avoid exposing the user's body surface to UV rays.

6. Fluorescent lamp

  • There is a fluorescent tube inside the cabinet to provide sufficient light during operation.

7. HEPA-Filter

  • The high-efficiency particulate air filter is located inside the cabinet, making the operating environment more sterile.
  • The pre-filtered air passes through the filter, which retains fungi, bacteria and other dust particles.
  • The filter ensures a sterile condition inside the cabinet, reducing the chance of contamination.

Principle/mode of operation of the laminar flow hood

Laminar Flow Hood/Cabinet: Definition, Parts, Principle, Types, Uses (2)


  • The laminar flow cabin principle is based on the laminar flow of air through the cabin.
  • The device uses internal airflow through one or more HEPA filters to create a particle-free environment.
  • Air is drawn in through a filter system and then expelled over the work surface as part of the laminar airflow.
  • The air first flows through the filter mat or the pre-filter, which enables an optimized air flow within the housing.
  • The blower or fan directs air to the HEPA filters.
  • HEPA filters trap bacteria, mold and other particles so the air you expel is particle-free.
  • Some of the exiting air then passes through the perforation in the bottom rear edge of the cabinet, but most of it passes through the workbench as it exits the cabinet toward the operator's face.
  • The laminar flow hood is closed on the sides and a constant positive air pressure is maintained to prevent contaminated outside air from entering the cabinet.

Procedure for operating the laminar flow booth

The procedure to be followed when operating a laminar flow cabinet is given below:

  1. Before operating the laminar flow cabinet, the cabinet must be inspected to ensure that there are no UV sensitive items inside the cabinet.
  2. The hood glass shield is then closed and the ultraviolet light is turned on. UV light should be maintained for approximately 15 minutes to ensure countertop surface sterilization.
  3. The ultraviolet light is then turned off, saving about 10 minutes of time before the airflow is turned on.
  4. The air flow is switched on about 5 minutes before the start of operation.
  5. Then the glass cover is opened and the fluorescent lamp is also switched on during operation.
  6. To ensure better protection, the cabinet work table can be treated with other disinfectants, e.g. B. 70% alcohol sterilized.
  7. After the work is completed, the air flow and the fluorescent lamp and the glass shade are closed.

Cabinet types with laminar flow

Depending on the direction of air movement, laminar flow cabins are divided into two types:

1. Vertical cabin with laminar flow

  • In vertical flow cabinets, air flows from the top of the cabinet directly to the bottom of the cabinet.
  • A vertical airflow hood does not require as much depth or space as a horizontal airflow hood, making it more manageable and reducing the likelihood of airflow obstruction or contaminated air moving downstream.
  • The vertical laminar flow cabinet is also considered safer because it doesn't blow air directly at the person conducting the experiments.

2. Horizontal laminar flow cabinet

  • With horizontal laminar flow cabinets, the ambient air comes in behind the bench, which is then blown onto the HEPA filters by the fan.
  • The filtered air is then discharged horizontally into the work environment.
  • An advantage of this cabinet is that the air flow parallel to the work space cleans the environment at a constant speed.
  • The eluent air falls directly on the operator, which can reduce the safety level of this type of laminar flow cabinet.

Laminar flow hood used

The following are some common uses of a laminar flow cabinet in the laboratory:

  1. Laminar flow cabinets are used in laboratories for contamination-sensitive processes such as plant tissue culture.
  2. Other laboratory processes can be performed inside the cabinet, such as: B. preparing media plates and growing organisms.
  3. The operation of particle-sensitive electronic devices is carried out inside the housing.
  4. In the pharmaceutical industry, drug preparation techniques are also performed inside the cabinet to ensure a particle-free environment during operation.
  5. Laminar flow cabinets can be tailor-made for some special tasks and can also be used for general laboratory techniques in the microbiological and industrial fields.

Also read:

  • Biological Safety Cabinets (BSC) - Lessons with examples
  • Biosafety cabinets - definition, classes (I, II, III) and types
  • 22 types of spectroscopy with definition, principle, steps, applications
  • Microbial culture media: definition, types, examples, applications
  • Biosafety Levels (BSL-1, BSL-2, BSL-3 and BSL-4)
(Video) Use of Laminar flow 2021


When operating with laminar air flow, the following things must be observed:

  1. The laminar flow cabin must be sterilized with UV light before and after the operation.
  2. UV light and airflow should not be used at the same time.
  3. Work should not be carried out when the UV light is on.
  4. The operator must wear a lab coat and long gloves.
  5. The workbench, glass guard and other components inside the cabinet must be sterilized before and after the work is finished.

references and sources

  • Collins CH, Patricia M and Lyne JM (1995). Collins and Lynes Microbiological Methods, Seventh Edition. Grange, Butterworth, Oxford.
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8 thoughts on “Laminar Flow Cover/Cabinet – Definition, Parts, Principle, Types, Uses”

  1. This is a very detailed and very understandable text, much appreciated.


  2. Hello, what is the best and safest laminar airflow for use in microbiology labs in pharmaceutical industry?

    (Video) Laminar Air Flow: Principle, parts, types and uses


  3. May I know the price of laminar airflow?


  4. I have an open laminar flow hood but no glass filter. It's an open cabinet that contains a small ultraviolet light inside. However, the problem with this type of case is that there is no glass filter, and I'm actually a bit worried about having to expose myself to UV light every time I need to turn it on or off since there's no timer . .for the UV lamp. So please any suggestions as to how this could be harmful? Thank you for considering my comment.


  5. very informative thank you
    Notes on Microbiology


    (Video) Laminar air flow hoods | Uses and functions | What is laminar flow?

  6. Clarifying the difference between vertical and horizontal LAF bench and how it differs from biosafety booths.


  7. Thank you for your encouragement


  8. very informative
    Many Thanks


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(Video) laminar air flow | Types of laminar air flow | vertical & horizontal laminar air flow | LAF

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What is the principle of laminar flow hood? ›

The fan or blower sucks the air, which is filtered through the filter pad. This filtered air then passes through the particulate filter, which facilitates the removal of micro contaminants such as bacteria or dust. A sterile work environment can thus be achieved within the working area with a uniform flow of air.

What are the parts of laminar air flow? ›

Parts of a Laminar Air Flow Cabinet
  • Enclosure. This is basically a box which provides the voluminous area to act as a sterile environment. ...
  • Work Surface. Also made of stainless steel, this is the flat table for you to work on inside the enclosure. ...
  • Pre-filter. ...
  • Fan or Blower. ...
  • HEPA Filter. ...
  • UV Lamp. ...
  • Illumination. ...
  • Controls.
13 May 2022

What is laminar flow hood and its uses? ›

Laminar flow hoods protect the working environment from dust and other airborn contaminants by maintaining a constant, unidirectional flow of HEPA-filtered air over the work area.

What are the types of laminar flow? ›

The two main types of laminar flow hoods are horizontal and vertical. Horizontal laminar flow hoods pull air from the environment; the air goes through a filter and then blows smoothly out the front of the hood back into the room.

Who discovered the principle of laminar flow? ›

History. The distinction between laminar and turbulent regimes was first studied and theorized by Osborne Reynolds in the second half of the 19th century. His first publication^{1} on this topic is considered a milestone in the study of fluid dynamics.

How is laminar flow defined? ›

Laminar flow can be defined as the motion of a fluid where every particle in the fluid follows the same path of its previous particles. From: Drilling Engineering, 2021.

What is the principle of RLAF? ›

The main principle behind reverse laminar airflow is that it makes use of negative pressure inside the booth. This pressure prevents the escape of fine powder from the work area to the external environment.

What is laminar flow number? ›

Flows at Reynolds numbers larger than 4000 are typically (but not necessarily) turbulent, while those at low Reynolds numbers below 2300 usually remain laminar. Flow in the range of Reynolds numbers 2300 to 4000 and known as transition.

Which filter is used in laminar flow? ›

Laminar air flow systems equipped with HEPA (High-Efficiency Particulate Air) filters remove 99.97% of particles > 0.3 μm. In addition, LAF creates a homogeneous flow of air in the operating room with very little turbulence.

What are the 3 types of flow? ›

Key Takeaways. There are three fluid flow regimes: laminar, turbulent, and a transition region. The conditions that lead to each type of flow behavior are system-specific.

What is flow and its types? ›

The Different Types of Flow
Physiological occurrenceFlow direction
Oscillatory laminar flowAccepted as a means of turbulence simulation using flow chambersPeriodically changing
Turbulent flowRare, during pathophysiological processesChanging
3 more rows

What are the types of flow system? ›

There are mainly two kinds of flow, such as:
  • Laminar flow - Laminar flow would be the continuous movement of flowing fluid that follows or respects streamlines. ...
  • Turbulent flow - Turbulent flow is characterized by erratic property modifications in the flow.

How is laminar flow measured? ›

There are four simple steps an Alicat differential pressure device uses to calculate a mass flow rate.
  1. Convert turbulent flow into smooth laminar flow.
  2. Measure the pressure drop across a flow channel.
  3. Calculate the volumetric flow rate.
  4. Calculate a standardized mass flow rate.

What is laminar flow example? ›

A different example of laminar flow occurs everyday inside of you. Blood flowing throughout your body is flowing laminarly. One last example of laminar flow is syrup, or honey, flowing out the nozzle. Because the liquid is so thick, or viscous, the Reynolds number indicates that the flow is very laminar.

What is laminar flow PDF? ›

Laminar flow causes the viscosity to generate friction forces in the fluid adjacent to the layer of. the relative motion. To counter the effect of this other shearing forces must be in action. These. shearing forces are not friction forces since there is no sliding motion of fluid adjacent to the.

What are the 4 properties of fluids? ›

Temperature, density, pressure, and specific enthalpy are the thermodynamic properties of fluids. Physical properties: These properties help in understanding the physical state of the fluid such as colour and odour.

What is laminar shape? ›

The laminar flows cause velocity profiles in the channel to appear typically parabolic in shape, which can lead to a relatively broad residence-time distribution.

How many filters are in RLAF? ›

Triple Stage filtration

Differential Pressure Gauge: 3 Nos. to monitor pressure drop across three stages of filters.

What is LAF HVAC? ›

What is a Laminar Flow unit? Laminar Flow units are used to blow filtered air above areas requiring a sterile environment. The right shape, physical separation from the surrounding areas and temperature control are critical factors when choosing and designing LAF equipment.

What is LAF filter? ›

LAF : Laminar Air Flow – Airflow which is linear and positive up to working surfaces and thus prevents contamination of surrounding viable/ non viable particulate matter in aseptic handling.

What is the value of laminar? ›

Whenever the Reynolds number is less than about 2,000, flow in a pipe is generally laminar, whereas, at values greater than 2,000, flow is usually turbulent.

What are 3 types of filters? ›

Four Major Types of Filters

The four primary types of filters include the low-pass filter, the high-pass filter, the band-pass filter, and the notch filter (or the band-reject or band-stop filter).

What are the 5 types of filters? ›

There are many different types of filters used in electronics. These filter types include low-pass, high-pass, band-pass, band-stop (band-rejection; notch), or all-pass. They are either active or passive.

What are the 4 factors of flow rate? ›

The viscosity, density, and velocity of the fluid. Changes in the fluid temperature will change the viscosity & density of the fluid. The length, inner diameter, and in the case of turbulent flow, the internal roughness of the pipe.

What are the two types of flow rate? ›

What is flow rate? There are two types of flow rate: instantaneous flow rate and integrated flow rate.

What is called flow? ›

: a smooth uninterrupted movement or progress. a flow of information. : stream.

What is the use of flow? ›

The most common use of Flow is to trigger notifications. When a new lead is added to Microsoft Dynamics CRM, for example, an automated workflow can send sales representatives an email or text message with details about the lead. Flow can also be used to copy files.

What are the 7 conditions of flow? ›

Flow conditions – Csikszentmihalyi's summary
  • Clear goals. ...
  • Immediate feedback. ...
  • Balanced opportunity and capacity. ...
  • Deep concentration. ...
  • Being in the present. ...
  • Control. ...
  • Altered sense of time. ...
  • Egolessness.
15 Feb 2018

What are the parts of a flow system? ›

The logistics system for discrete parts flow systems are composed of three categories: materials management system, material flow system, and physical distribution.

What are the 4 different types of fluid flow? ›

The most familiar types of fluid flow can be steady or unsteady, compressible or incompressible, viscous or non-viscous, rotational or irrotational, to name a few characteristics.

What is flow system Model? ›

1 What Is a Flow Model? The flow model, at its base, is a simple graphical representation of how information and artifacts flow through the system as it is used. It's essential to identify the basic system flow as early in usage research as possible.

What is the purpose of a flow hood? ›

Laminar air flow hoods function as exhaust systems. They draw in the polluted air, filter it, and release the pure air in the room. Workstations at industrial workplaces equipped with laminar air flow hoods are called laminar workstations.

What is the importance of laminar air flow? ›

The two major purposes of laminar flow hoods are filtering the air and protecting scientific substances. Apart from laboratories, these features come in use in various industries including, Research regarding plants. Cleaning industries.

What is the benefit of laminar flow? ›

The principle of laminar flow was first discovered in 1960; laminar flow workstations are used to move air safely through laboratory enclosures. They direct unrestricted airflow towards sterility, prevent contamination, and reduce potential turbulence.

What are flow hoods? ›

A laminar flow hood is an enclosed workstation designed to prevent contamination and provide a sterile work area for biological experiments.

How do you clean laminar air flow? ›

Clean the ceiling of the unit first. Clean the back wall (of a vertical laminar flow hood) next, going from top to bottom. Clean the sides (swiping from top to bottom in overlapping lines). The work surface should be the last surface cleaned, beginning in the back and ending at the front of the unit.

What is laminar air flow temperature? ›

Laminar air flow cabin. Incubator controlled O. Fridge (4°C) Freezers (−20°C, −80°C, −150°C)

What is called laminar? ›

laminar flow, also called streamline flow, type of fluid (gas or liquid) flow in which the fluid travels smoothly or in regular paths, in contrast to turbulent flow, in which the fluid undergoes irregular fluctuations and mixing.


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