The fume hood protects users from inhaling chemicals by constantly pulling air into the hood and exhausting it out of the building. Fume hoods also provide protection in the event of an explosion or fire. However, excessive air velocities can cause turbulence that may bring the contaminants back into the user's breathing zone. The air velocity measurements are noted on the hood. How to Use a Fume Hood Adjust the sash.
Position sashes at the arrows to ensure proper airflow velocities at the work opening.
Adjust the sash to shield yourself from splashes or flying objects. Horizontally sliding sashes can be used as a body shield by wrapping your arms around the sash panel as you work. Check that the hood is working properly. By law, all hoods must have a visual indicator that tells the user if the hood is working properly. New hoods often have pressure gauges and alarms.