AIRFOIL FUME HOODS
DESIGNED TO REDUCE TURBULENCE
Air foil fume hoods are a type of fume hood with an aerodynamic entrance shape. Instead of having square faces, air foil fume hoods have a gentle slope on the bottom front air foil that reduces turbulent air patterns and increases laboratory safety.
When air enters a fume hood, it does so both vertically and horizontally. When fume hoods have square entrances, the air approaching both vertically and horizontally collides at the entrance point. The colliding airflow results in a large roll of turbulent air at the front of the hood. Hood contaminants are moved from the interior of the hood to this roll. If there are certain air patterns in the room, or even if someone walks by the hood and creates a draft, the contaminants at the front of the hood can be easily sucked out into the room, where they will mingle with the laboratory air. However, when a correctly designed air foil is part of the fume hood’s design, turbulent air patterns disappear.
AIR FOIL FUME HOOD DESIGN
To ensure the air foil does its job, spacing under the foil should be about one inch, and the slope of the foil should be between 20 and 30 degrees. More extreme slopes and more space under the foil can result in an air roll.
In some situations laboratory requirements necessitate a spacing of 1 ¼ inches to accommodate tubing and other materials. In situations that require more spacing, the roll of turbulent air can be avoided by increasing the foil’s degree of slope. For example, if a slope of 20 degrees is ideal for a foil with a spacing of 1 inch, then a slope of 30 degrees may accommodate a foil with a spacing of 1 ¼ inches without ill effects.