Working with volatile chemicals or experimental pathogens requires extreme caution on the part of the laboratory worker. Fumes that emanate from a mixture could be harmful to the person, as well as anyone in the immediate area. A fume hood is an essential item for any industry that has constantly emitting vapors from a damaging substance, such as carbon monoxide. Hood manufacturers have created a number of different models to serve a growing experimental laboratory industry.
A fume cabinet consists of an enclosed table space with a movable entrance point for the hands and arms; workers stand or sit in front of the opening to work with chemicals and microorganisms. A specially designed air flow moves through the hood to keep the fumes from permeating the interior of the laboratory. Depending on the fume hood model, the vapors are expelled outside or adsorbed into specific internal filters.
These laboratory fume hoods allow businesses to experiment with various substances that they otherwise would not be able to touch; some substances have vapors that can burn the eyes and throat upon immediate contact. However, the safe experimentation will eventually create a product or solve a problem in the world to better the environment or people’s health, depending on the goal of the company.
The most common of the fume cupboards is a ducted version. Fume extraction occurs by moving the forced air through the hood and into an attached duct; the duct is installed between the hood and the outside of the building. A series of filters clears the contaminated air throughout the duct path so that the expelled air into the atmosphere is free from harmful substances. In the past, this model was the only one available that could effectively keep workers and the environment safe from the damaging vapors.
A ductless fume hood negates the need to have a complex ductwork system installed within the building. For some small to medium businesses, this is an extremely inexpensive way to keep employees safe while working with volatile substances. Fume extraction occurs through multiple filters set within the ductless fume hood itself; the filters adsorb the harmful chemicals through specialized fume extractors.
Two main filter types are used as fume extractors, including HEPA (High-Efficiency Particulate Air) and carbon. These fume cupboards use the process of adsorption across both filter types to trap molecules; depending on the fume cabinet model, either chemical or electrical bonding is used to keep harmful molecules from escaping. Chemical filters react with the passing molecules and effectively stick them to the carbon surface. In contrast, electrical filter versions excite the passing molecules and force them to adhere to the internal filter.
Another ductless model is called a portable fume hood. These specialized laboratory fume hoods usually have wheels with locks so that workers can move them between experimental room areas. The advantage of the portable fume hood is that companies can save money on purchasing multiple chemical fume hoods for separate rooms. Unless workers need to work simultaneously, employees can share one or two hoods on a daily basis.
Using a chemical fume hood requires attention to rules and regulations. Fume hood safety parameters need to be discussed and applied everyday that the hoods are used; workers need to make sure that the air flow is working correctly to remove all vapors, as well as wearing protective gloves and clothing. Without proper fume hood safety, workers can easily be injured externally or internally from the vapors. In fact, it is best to keep all body parts out of the hood unless a worker needs to mix or move a container.