A great asset for researchers working with toxic or hazardous materials is a fume hood. The hood is designed to limit exposure to fumes by safely exhausting them. Fortunately, many laboratories at Texas Tech have fume hoods for faculty and students to use. The hood is usually a large cabinet with a clear window on one side called a sash that can be raised and lowered. Experiments can be conducted inside the cabinet’s work area. In addition, the sash can act as a partial shield and provide a degree of protection for those working in the lab.
It is recommended the sash to the fume hood always be closed when not in use. A 2011 incident at Texas Tech University involved a glass bottle that exploded in a fume hood where the sash was left open.
The open sash provided an unobstructed path for glass shards to be projected more than 56 feet away from the explosion. Fortunately no one was in the lab at the time of the explosion, but the accident provided a critical reminder to always close fume hood sashes when not in use.
It also is important to make sure the hood is functioning properly before each use. In accordance to OP 60.04, Environmental Health and Safety (EH&S) personnel will survey each laboratory fume hood a minimum of once a year to test airflow performance. The date and the results of the test will be recorded and affixed to a tag on the fume hood. Some fume hoods on campus have a gauge indicating proper airflow though the machine. In addition, a tissue taped to the sash that can be pulled gently into the hood can also provide an indicator as to whether or not the machine is venting properly. Users of the fume hood should contact Building Maintenance and Construction at (806) 742-3301 if a fume hood is not working properly.
Once verified the machine is working properly, it is recommended items used in the experiment be placed at least 6 inches inside the hood to help keep vapors from escaping. The sash should be lowered to its optimum position as determined by EH&S arrows are placed on front sides of hood to indicate slash location. Remember, the fume hood sash is not an appropriate substitute for wearing personal protective equipment.
Because fume hoods can be large and take up valuable lab space, it may be tempting to use the space inside the hood for extra storage. This is highly discouraged since storing unused items inside the hood can negatively affect the hood’s performance by disrupting airflow. Large pieces of equipment placed directly onto the work surface can also block airflow and cause unwanted turbulence inside the hood. Elevating the equipment a few inches off the surface can help minimize the turbulence.
In order to increase lab safety, make sure all lab personnel are trained in the proper use of fume hoods.
Additional information about fume hood safety can be obtained online at:
Professor Dominick Casadonte emphasizes the importance of safety in the chemistry labs at Texas Tech.
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This information is not exhaustive and should not be construed as containing all the necessary compliance, safety, or warning information available. Please make sure you consult with EH&S or appropriate supervisors for all safety information and procedures.