General Fume Hood Operating Features
Typical Chemical Fume Hood Features
1. A Sash is a movable glass panel that covers the face area of a fume hood. Sashes can be vertical, horizontal, or a combination of the two. Many hoods are installed with a sash stop, which stops the sash at approximately an 16-18 inch work level.
NOTE: **Sash stops should never be removed, overridden, or modified. It is recommended that all lab work in a properly functioning fume hood be performed at the sash stop level or lower whenever possible.**
2. Alarms, sensors, controls, and gauges are included to provide laboratory personnel with a constant reading of fume hood performance. If the face velocity falls below an acceptable work range, the hood sensors will trigger an alarm to notify personnel. Hoods usually go into alarm mode either because the sash has been raised above the normal working height of 18" and the hood can no longer exhaust a sufficient amount of air. When a hood alarm sounds, no chemical work should be performed, close the sash to a lower height or completely, until the exhaust volume is increased to a safe operating level. If the alarm situation does not remedy itself, contact KU Facilities Operations for adjustment of air handling system exhaust and any fume hood maintenance issues.
3. Air foil or sill, is located at the front of the hood beneath the sash. It creates a smooth air flow, minimizing turbulence of the air entering the hood.
REMINDER: **All work should be done at least six (6) inches into the recessed work area behind the sill.**
4. Air Jambs are vertical sills or side posts at the front of the hood. These are tapered to promote smooth air flow into the hood.
5. Baffles are movable panels located on the back wall of the hood that create slots in which air is exhausted. The pattern of the air moving into and through the hood is determined by the setting of the baffles. Once installed, they should not be readjusted by laboratory workers.
Developed By: KU Department of Environment, Health & Safety,