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Do You Know What Type of Laminar Air Flow Cabinet You Need?
So you want to find out about laminar air flow cabinets? That’s great news, because you have come to the right place. After reading this concise yet informative article you will gain an understanding in the different types of laminar air flow cabinets available and will allow you to choose the best design for your laboratory experiments. There are 2 main types that are discussed within the article: - vertical laminar airflow hoods and horizontal laminar airflow hoods.
So What is a Laminar Airflow Hood?
Laminar airflow cabinets (or laminar flow hoods) work by controlling particulates that would otherwise contaminate your work. Removal of particulates provides a sterile, dust-free work area. There are two different types of laminar flow cabinets, which is determined by their directional airflow properties: Vertical laminar airflow hoods and horizontal laminar airflow hoods. Laminar hoods are currently used over a range of industries from medical research to electronics.
As suggested, the airflow within the laminar hood contains a vertical displacement airflow and is the popular choice for many people like yourself. Vertical laminar airflow hoods work by reinforcing the gravitational effect on particles, which get swept out via either holes built into the workbench, or via a front access area. Because the particulates are subject to Newtonian motion they would settle on the work surface or on the floor anyway but the airflow facilitates quicker movement. Because particles end up on the floor, you are protected against your materials and your materials are protected against the environment. It is advised to only use this laminar hood with hazard level 2 and 3 materials because level 4 materials require a fully sealed bio-safety cabinet for safe use. Vertical laminar airflow hoods are also an ideal choice when your laboratory space is limited as the filter is installed on top allowing the hood to be installed on a standard laboratory workbench. Other advantages include the ability to compound sterile products, easy access to the filter and low turbulence when air comes into contact with large equipment.
Vertical laminar flow hoods have some potential disadvantages as well. Notably, placing your hands, materials or equipment on top of other items obstructs the airflow and creates turbulence which reduces their ability to remove particles, leading to a greater risk for contaminating your work. Depending on the Vertical laminar flow hoods placement, doing a routine filter change can pose a safety risk if a stepladder is required to gain access to the overhead filter on top of the vertical laminar flow hood.
The second type of laminar flow hood is the horizontal laminar airflow hood which directs airflow from the cleanest air source, which is at the back of the hood, towards you, the user. Unlike their vertical airflow counterparts, horizontal laminar airflow hoods are designed to protect your work, but not you. You are positioned downstream of your work to protect it but you are left exposed to any contaminants that are not filtered out before reaching you. For this reason, horizontal laminar flow hoods can only be used with hazard level 2 and 3 materials.
Because the airflow is directed horizontally across the work surface rather than directly at it, the air turbulence that occurs in vertical laminar airflow hoods is not a factor. However, larger samples can disrupt the airflow or contaminate downstream samples. Other advantages of the horizontal laminar airflow include allowing you easier access to your work because there is no sash to open and close; and any particulates picked up by your gloves are less likely to contaminate the sample because you are downstream of it.
However, because the filtration system is placed at the back of the laminar hood instead of stacked vertically, more laboratory space is required for horizontal systems. Another disadvantage of horizontal laminar airflow hoods is that the whole cabinet usually needs to be moved in order to change the filter.