Use, Function and Limitations

A chemical fume hood is the main piece of laboratory equipment that protects workers when handling hazardous chemicals. Fume hoods are a type of engineering control designed to protect the worker from chemical hazards. Fume hoods are connected to an independent exhaust system that discharges the air from inside the fume hood to the outside of the building.  Fume hoods are designed to be workspaces and not to be used for storage. Some chemical or a small satellite accumulation area may be kept in a fume hood so long as it does not disrupt airflow or does not inhibit the workspace.

Chemical Fume Hoods are checked for use and function during annual laboratory safety assessments by the lab safety team. Ductless Fume Hoods are prohibited unless pre-approved by EHS-SRM staff.  Ductless fume hoods do not provide adequate protection and are designed for specific processes and procedures and not to be used as a replacement for a vented or ducted fume hood.

The following general guidelines must be followed for safe handling
of hazardous chemicals: 

• Operate the hood at the proper sash height. Sash height will vary based on the fume hood. Most fume hoods will have a mark as to the appropriate sash height.
• Minimize the release of contaminants into the work area by reducing pedestrian traffic in front of hoods, particularly during hazardous experiments.
• Do not block the airfoil. The airfoil provides airflow across the floor of the hood, especially when the sash is closed. <br>(e.g. absorbent paper)
• Work as far inside the hood as possible, at least 6 inches from the front edge with the sash face between you and the task at hand. 
• Do not use the hood as a storage cabinet for the chemicals or equipment. Materials stored in fume hoods should be kept to a minimum and stored in a manner that will not interfere with airflow. Evaporating chemicals for disposal purposes is not allowed. 
• Wear protective equipment! Fume hoods do not prevent accidents or chemical splashes. Personal protective equipment (safety glasses, gloves, aprons, etc.) appropriate to the conditions must always be worn.
• Close sash when finished with hood work or when leaving experiments or chemicals unattended. This procedure will contain fires and explosions within a hood.