Different types of clean benches are used for several different reasons. In this case, we are introducing you to the vertical laminar flow clean bench. The first thing you must consider when purchasing a clean bench us the size and type of object you are going to be working with. This type of airflow are often chosen because vertical laminar flow resemble, on a small scale, the design of a cleanroom, in which fan/ filter units are typically positioned in the ceiling. This means that by directing the laminar flow downward, vertical laminar flow reinforces the effect of gravity and sweeps particles out of the enclosure, generally through a front access area.
One important aspect you have to keep in mind is the type of objects you are going to be working with in your laboratory. You should know that large objects can block the airflow from a horizontal flow bench, creating large turbulent areas on the downstream side of the object. These large turbulent areas often become contaminated as ambient contamination is drawn toward them. Is this moment when you have to start considering vertical flow, because air enters the work zone from the top and flows downward, surrounding the object within the work area. Air flows on the front, sides, and rear, bathing the object on all sides with clean HEPA filtered air. Vertical flow air then continues down through a perforated or rod-type table top, or turns and flows out the front of the bench if it’s a solid-top table.