Selecting a Chemical Fume Hood: It may be easier than you think!
Choosing the right fume hood can seem daunting. There are so many options to choose from and so much information to gather in order to make an informed decision, but help is at hand! First, spend a few minutes answering the questions below. Once you have answered each question, you will have successfully established the criteria necessary for choosing a fume hood system. Second, call a Labconco Product Specialist at 800-821-5525 to have a product recommendation made based on your answers. For complete information, view or download the booklet, How to Select the Right Laboratory Hood System.
- What's goin' on in the hood? Try to document as much as you can about the application. What chemicals are used and how are they used? Is heat involved? What volumes of chemicals will be used at a given time? What's really goin' on in there?
- Does size matter? How wide do you want the fume hood? Labconco offers fume hoods from 30" to 16' wide with many options in between. Consider any equipment that will be used inside the hood. What are those dimensions? This information is essential in determining how deep the hood needs to be to house your equipment.
- Fixtures at your service. Service fixtures include electrical outlets, compressed air, laboratory gas, vacuum, and water. Gooseneck faucets are also available. Finally, if fixtures are required, determine if they will be factory- or field installed.
- Ready for the bling? Always consider what accessories you may need to complete the installation. Do you need a work surface and base cabinets, or will existing casework be used to support the hood? If base cabinets are needed, do you need acid storage, solvent storage, non-chemical storage, or a combination? How about ductwork? Will your HVAC contractor provide it?
- Is this exhausting? Will there be a dedicated blower (exhaust fan) for this hood, or will it connect to a central system? If it connects to a central system, will it be constant volume or variable volume? If you need a blower, proceed to the next question.
- Blowers-built-in or à la carte? A built-in blower is easier and less expensive to install than a remotely located blower. On the down side, it can be noisy and it puts ductwork under positive pressure, so it should not be used in toxic applications. Built-in blowers are usually limited to smaller hoods with short, straight duct runs. A remote blower, though more complex to install, can be sized for the specific situation and puts the ductwork under negative pressure. Should a leak develop in the ductwork, fumes are drawn into the blower instead of escaping into areas surrounding the duct. If a remotely located blower is needed, move on to the next question.
What's on the rooftop? Will the duct run directly to the roof or will it make some turns before reaching the roof? What diameter of duct will be used? Once the duct penetrates the roof, a final 90° elbow will be needed to turn the duct horizontal, then 3' to 5' of straight ductwork is needed between the elbow and blower. Finally, the exhaust stack should include a zero-pressure weather cap (not a gooseneck or mushroom cap) and should end at least 10' above the roofline to allow the fumes to be dispersed into the airstream and not be returned back into the building's air handling equipment.
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