Laboratories and research facilities deal with sensitive materials, chemicals and samples like tissue cultures on a regular basis. Due to their sensitive nature, they need to be studied and worked upon in a contamination free environment. A laminar flow hood is an equipment that is designed to create such a sterile atmosphere that is needed for the operation of lab specimens. It has a simple working concept – to create a continuous laminar flow of clean air that sweeps away all foreign particles in a designated area.
Laminar flow hoods are available in two configurations depending on the direction of air flow. A vertical laminar flow hood has the air flowing from the top of the equipment towards the bottom. And in horizontal laminar flow hood, the air flows parallel to the workspace, from the rear end towards the front. In both types of hoods, a filter is used to create the flow of purified air.
Let us understand the mechanism and uses of a horizontal laminar flow hood in detail.
What is a Horizontal Laminar Flow Hood?
A horizontal laminar flow hood is basically a special type of workbench. It is enclosed from all sides except the front, and the area inside the enclosure is the main workspace where necessary operations are performed.
At the back of the hood, a High Efficiency Particulate Air (HEPA) filter is present. This filter has special fibres inside of it that are arranged in a specific way. Once activated, a HEPA filter will pull in air from the surrounding environment and purify it from particles. The arrangement of fibres inside traps all pollutants and micro particles, allowing only clean air to pass through. This clean air is blown at a constant speed in a smooth laminar flow, from the rear end of the hood towards the front. So any contaminants present in the workspace of the hood are blown away with the flowing air.
In this way, a horizontal laminar flow hood effectively provides a clean and uncontaminated working space for the sensitive materials and specimen used in laboratories.
Proper use of Horizontal Laminar Flow Hood
In a horizontal laminar flow hood, the air sweeps away contaminants towards the front of the workbench. So the particles and pollutants will be concentrated at the front area of the workbench, while the region close to the filter at the rear end will be most sterile. Thus, it’s important to place the specimen or chemicals near the filter for higher efficiency.
Since the air flows straight towards the operator, so these hoods are only suitable for protecting the products and not the operator. This means that it’s not suitable to use toxic chemicals and biohazardous materials inside a horizontal laminar flow hood. Also, the use of large equipment’s inside the workbench should be avoided, as they can disrupt the laminar flow of air and create some turbulence, which is not desired.
Horizontal laminar flow hoods do not have a sash at the front, which provides a larger working space. However, the workspace should not be congested with objects, as this will again disrupt the flow of air and lead to the formation of turbulence.