Fume Hood Research Paper

Since their inception, fume hoods have been an integral part of any professional

laboratory that works with potentially hazardous chemicals. “But what exactly is a fume hood?”

you may be asking. Well, by most definitions a fume hood is a specifically-designed cabinet in

which an individual is able to work with a chemical in. To help in the mitigation of stray spills

flying back toward the user, the fume hood has specially-treated glass panes, called sashes,

which may be raised or lowered to act as a shield against backsplash. In order for protection

against vapors given off from chemicals and their reactions, the fume hood also has a

ventilation system which, using air pressure, forces the harmful vapors into a chimney-like

ventilation duct in the top of the hood. This usually is then ejected though a roof stack, but it

could also go through a filtration system to reduce the environmental effects of hazardous

chemicals.

However, the laboratory housing the fume hood also needs special conditions to be

considered up to standard. A lab with a fume hood cannot have recirculation of air in any part

of it; on a similar note, any windows in the lab have to be kept closed at all times, and the

overall air pressure of the lab must be less than the rooms adjacent in order to ensure that

contaminated air will not try to go the wrong way. All fume hoods cannot be place in such a

way that they are directly opposite of a work station, nor can they be in a location that one

would have to pass directly by in order to enter or exit the lab. Speaking of doorways, a

laboratory with fume hoods should have at least two doors. This is done so that if an accident

occurs and causes one door to be blocked, there is another means of escape. If there is only

one door, then the hood must be placed on the side of the room opposite the entrance.

Once a fume hood has been set up in accordance to proper safety standard, it can then

be used. However, like any other piece of equipment, there is a right and safe way to use one,

and there are wrong ways to do so as well. One of the first things that one should always do

when using a fume hood is to check that the ventilation is actually on. If it is then one should

then check the airflow indicator; an airflow indicator is the small, light paper that is attached to

the sash which shows which way the air is flowing, so that one knows that the ventilation is

working in the right direction.

Once the fume hood itself is operating safely, one must then consider safe actions that

they themselves perform. The first thing one should consider is whether or not a safer chemical

can be used in place of a hazardous one; if such an option is viable, it should be taken to

mitigate potential danger to oneself, others, or the environment. When working with a

chemical one should keep the chemicals at least six inches in the hood. One should also lower

the sash as far as feasible to work with, not only for one’s own protection, but also to keep the

machine running efficiently. When lowering the sash, do so in a slower manner, as a quick

motion can cause air fluctuations, which can inefficiencies in ventilation. If, at any moment, the

fume hood were to experience a malfunction and shut off, one should halt the experiment and

close chemical containers. One should not store chemicals in the hood, as it can lead to the

hood becoming cluttered and inefficient with air flow.

Fume hoods, being such an important piece of laboratory equipment, must undergo

several levels of maintenance. A fume hood should be checked daily to see that it is,

uncluttered of chemicals and other miscellaneous objects and that the airflow indicator is still in

place; if an airflow indicator is missing, it should be immediately replaced. Every once in a while

the fume hood should have its face velocity (the speed at which air comes through the front)

measured with a velometer by taking the average of at least six readings. Most fume hoods

have been measured to have a face velocity of about 30 meters per minute when the sash is

open 18 inches. Thus in most cases if the recorded measurements are significantly lower than

that it would be a good idea to seek further maintenance and repair. Miscellaneous repairs

such as replacing fan blades should be done as per the instruction of the manufacturer.

The fume hood is an invaluable tool to any laboratory worker who deals with potentially

hazardous substances. It keeps the dangerous fumes and splash back away from the user, while

at the same time helping to keep the sample from being contaminated. However, that is only

when fundamental fume hood safety is used, and when the machine is properly maintained.

Thus it is paramount that such things are given a fair deal of attention, so as to prevent disaster

from occurring in the lab.