Fume hood
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A fume hood, fume cupboard, or just hood device common to chemistry laboratories designed to keep hazardous fumes out of the room air by exhausting them out of the building before anyone can potentially breathe them.
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Construction and location
Fume hoods are usually about 2 feet deep and 6 feet wide, allowing 2 people, or 3 with a squeeze, to work together on something. However they can be found in all sizes. They are generally set back against the walls and extend to the ceiling to conceal their ductwork. Because of their shape they are generally dim inside, so many have internal lights with gas-proof covers. The front is usually glass so you can see into it and able to move up and down.
Method of operation
If the hood is working properly, a constant air flow is created through the device, usually using fans, exhausting the air inside it through the top of the fume hood and out of the building or through a decontamination process if the fumes can't be released to the open air (eg. vinyl chloride).
Use
To determine whether a chemical is likely to require a fume hood for safe usage, its MSDS should be consulted. If there is doubt, use a hood.
If you are going to start using a hood you haven't dealt with before, read the manual, or even better ask the people who use it regularly how to use it as they will also know about any quirks or special conditions that the manual might not list.
If you already know about the hood you're going to use, begin by making sure no one else is using it or has left things in it. If it's free collect what you need to be in the hood (reagents and/or the experimental apparatus if the products will give off noxious fumes).
If the light in the hood is too dim to see (It probably will be, even if there's enough light in the room you'll be working in your own shadow) then turn on the internal light.
Stand (Or sit if there's a stool) where you'll be likely to be when you're working, then lower the glass front as far as you can without making it impossible to get your arms under it and work around.
A warning
Even though a properly functioning fume hood provides adequate ventilation be sure not to directly smell any chemicals directly even when using one. Doing this could cause severe damage to your trachea and lungs. Instead take your palm and wave it above the test tube or beaker to waft reduced amounts of the substance towards your nose. Template:Chem clipart --- Template:LaboratoryEquipment