Laboratories require a wide range of specialized equipment. One such piece is the laboratory fume hood. These devices help create a safe workspace by removing hazardous, volatile, and/or toxic particulates from the air in the work area and safely venting them elsewhere. However, when designing or remodeling a laboratory, it is important that the right sizing, design, placement, and usage steps are followed.
What Is a Laboratory Fume Hood?
A laboratory fume hood, sometimes called a chemical fume hood, is a device designed to draw air out of a specific area and vent it elsewhere. Fume hoods are enclosed on both the top and bottom, as well as three sides, leaving one side open for working. They are connected to ductwork, through which a fan motor moves air (and the particulates it contains) from the work area.
Why Is a Laboratory Fume Hood Necessary?
Many laboratories deal with volatile, dangerous, or even toxic compounds. These include:
If not controlled, these particulates could pose serious health threats to laboratory workers and others. Therefore, containing them and then moving them elsewhere is critical. This is the purpose of a fume hood – the containment, capture, and removal of dangerous particulates to help create a safer laboratory.
How Does a Fume Hood Work?
Fume hoods work by creating a contained environment and then capturing particulates within that environment. Containment is achieved by creating a sealed environment in which the worker will conduct experiments or study. Capture is achieved by using a fan motor to suck air in and up through ductwork, where it can be isolated. In some cases, particularly dangerous contaminants, such as perchloric acid fumes and radioisotopes, require additional precautions, including filtering and additional capture-related mechanisms located within the ductwork.
However, laboratory fume hoods have their limitations. For instance, they are designed only to capture fumes and other particulates within a specific area. They cannot capture contaminants from other areas of the laboratory. Each workstation where fumes, dust, toxins, or other particulates will be generated should be equipped with its own fume hood.
Installing multiple laboratory fume hoods within the same space requires careful planning, though. Because fume hoods pull in fresh air and then move that air out of the room (including the contaminants/particulates the air contains), it is necessary to have sufficient airflow within the space for all fume hoods when operating at the same time. This is also called “make-up air”, and if insufficient, fume hoods may not operate as designed, allowing particulates to escape.
Laboratory Fume Hood Usage Tips
While the function of laboratory fume hoods is easy to understand – they move air through a limited area, sucking contaminants out through ductwork – it is critical to use them correctly. Failure to do so can result in limited functionality, or even allow contaminants to spread throughout the room.
Close the Sash: One important usage tip is to ensure that you never work in the hood with the sash fully open. The sliding sash should be kept at 16 inches to protect your face and the contents of the fume hood from fires, explosions, spills, and other accidents. The sash should be fully closed when the fume hood is not in use.
Be Wary in Front of the Hood: Any disturbances or activity directly in front of the fume hood can cause turbulence in the airflow that disrupts operation. Limit activity directly in front of the fume hood during operation. This includes limiting open windows or doors, as well as pedestrian traffic, to help prevent drafts that might compromise operation.
Locate Permanent Storage Elsewhere: While fume hoods offer some storage capabilities, they are not designed for permanent storage needs. Use cabinets, shelves, and other permanent storage solutions for chemicals and other equipment.
Be Careful with Equipment Placement: While equipment can and should be used within the fume hood, avoid placing equipment where it may block sash closure, as this creates an unsafe situation.
Limit Body Exposure within the Hood: Keep your head and face out of the fume hood. While you may need to have your hands within the hood, limit this exposure as much as possible, and always wear appropriate protective gear.
Electrical Devices: All electrical devices should be connected outside the hood to avoid accidental fume/gas ignition from sparks when plugging/unplugging devices.
Always Check First: Before operating the fume hood, always check that it is in good working condition. Tape a strip of paper to the sash to show proper airflow and ventilation before beginning a project.
Be Prepared: Because fume hoods require electricity to operate, a power outage during use could be particularly dangerous. Make sure to have a plan of action to ensure protection and safety, particularly when using dangerous acids or hazardous chemicals.
A Trusted Solution
At Laboratory Design & Supply, we have over 23 years of in-depth experience in designing laboratory fume hoods to meet exacting specifications and requirements. We can also offer over 10,000 pieces of laboratory equipment and supplies to ensure safety and operability. Contact us today to learn more about laboratory fume hood design, fume hood usage, or fume hood certification.