Laminar air flow is an enclosed bench designed to maintain a working area devoid of contaminants. Many medical, microbiological and research laboratories require aseptic working environments in order to carry out specialized work. Laminar air Flow can provide the best solution. Laminar Flow Cabinets or laminar air flow is normally made of stainless steel without gaps or joints thereby preventing the accumulation of bacteria from collecting anywhere in the working area.

Components of the Laminar Hood are
• A Blower
• High-Efficiency performance Air filter (HEPA)
• A Plenum Chamber (Pressurized housing containing air at positive pressure)

How They Work
Laminar air Flow is also known as clean benches because the air for the working conditions is thoroughly cleaned by the precision filtration process. Laminar air flow operates by the use of in-flow laminar air drawn through one or more HEPA filters, designed to create a particle-free working environment and provide product protection. Air is taken through a filtration system and then exhausted across the work surface as part of the laminar flows process. Commonly, the filtration system comprises of a pre-filter and a HEPA filter. The Laminar Flow Cabinet is enclosed on the sides and constant positive air pressure is maintained to prevent the intrusion of contaminated room air.

HEPA (High-Efficiency Particulate Air) filters

HEPA (High-Efficiency Particulate Air) filters consist of a thin pleated sheet of boron silicate microfibres with aluminum separators. They are particulate filters which retain airborne particles and microorganisms (gases pass freely through)
Filtration occurs by five distinct methods:
1) sedimentation
2) electrostatic attraction
3) interception
4) inertial impaction
5) diffusion

Why Laminar Flow hood?
• Laminar Flow hood provide unidirectional, particle-free air flow to the working area by projecting air through a filtration system and exhausting it across a work surface in a laminar
• They provide constant airflow out of the hood and prevent room air to enter the laminar hood.
• The air flow removes contaminants introduced into the work area by personnel.

Uses
• Laminar Flow Cabinets are suitable for a variety of applications and especially where an individual clean air environment is required for smaller items, e.g. particle sensitive electronic devices.
• In the laboratory, Laminar Flow hoods are generally used for specialized work.
• Laminar Flow Cabinets can be tailor-made to the specific requirements of the laboratory and are also ideal for general lab work, especially in the medical, pharmaceutical, electronic and industrial sectors.

Types of Laminar Air Flow

 Laminar Air Flow can be a horizontal and vertical cabinet. There are other different types of laminar air flow with a variety of airflow patterns are available.
• Vertical Laminar Flow Cabinets
• Horizontal Laminar Flow Cabinets
• Laminar Flow Cabinets and Hoods
• Laminar Flow Benches and Booths

All ensure a workspace devoid of contaminants and may be tailored to the lab requirements.

Horizontal Laminar Flow Cabinets
In Horizontal Laminar Flow Cabinets airflow in a horizontal direction across the working area. The continuous air flow provides material and product protection.

Vertical Laminar Flow Cabinets
In Vertical Laminar Flow Cabinets filtered air flows vertically downwards onto the working area. The air can leave the working zone via holes in the base. Vertical flow cabinets can provide greater operator protection.

Biosafety

• No Large objects should be placed near the back of the hood. As these objects may contaminate everything downstream and disrupt the laminar flow pattern of air too.
• Waste and other items should never enter the hood. All calculations should be done before entering the hood.
• Hands should be cleaned with ethanol
• Do not touch your hair, face or clothing while working.
• Excess dust should be removed from items before introducing them into the hood.
• Hair should be tied while working
• Do not work with the cabinet UV light source illuminated.
• The cabinet must be on at least 5 minutes before starting biohazard work.
• The researcher should wear a closed-front lab coat and gloves.
• The gloves should overlap the lab coat
• All the required materials should be placed in the hood before initiating work to minimize in-and-out motions.
• Do not overload the working area or block front, side, or rear air grills which will restrict air flow.
• While operating the Laminar, the lab entry door must be kept closed and traffic minimized
• Do not use electric fans in the room while working this will seriously affect the unit’s airflow.
• Clean the hood with an appropriate disinfectant at the end of each operation.