Laminar Flow Hoods

Laminar airflow is air moving at the same speed and in the same direction. A laminar flow clean room typically moves air from filters in the ceiling down to the floor and out through an exhaust or recirculating air vent. This forces any particulate to the floor and out of the cleanroom to reduce the probability of contamination. To make a space cleaner, we increase the velocity of the air movement to improve this effect. The smaller the volume to clean, the less total air movement is required, which reduces the overall cost of the operation.

For contamination-sensitive processes, we can achieve a much higher level of cleanliness by reducing the air volume of the critical environment within a laminar flow bench. Whether a vertical or horizontal flow, laminar flow benches provide a localized ISO Class 5 (Fed. Class 100) area for added protection against contamination. Some examples of applications include laboratories, 797 drug compounding, IV preparations, electronics manufacturing and medical device assembly. Any process can be made cleaner within the confines of a laminar flow bench, regardless of it being in a clean room or not.

Things to consider when selecting a laminar flow hood:

• In cleanroom environments, consider air flow from clean to dirty. If work is done above the work surface, such as adding a sample to test tubes, vertical flow is best because the air is cleanest closest to the filter or where the sample is accessed. For applications such as agar samples, the most critical samples should be near the filter in a horizontal flow bench so they occupy the cleanest space and hands do not pass over them.
• When using a cabinet, let it run for several minutes before introducing samples to assure that all particulate is swept out of the area.
• Keep in mind the footprint of a unit, many of these benches are fully welded and shipped crated. If they will have to be brought in through narrow doorways or upstairs, it may be best to select a modular unit that ships knocked down.