The Importance of Fume Hoods and Ventilated Enclosures
The word fume comes from Middle English fum, from Old French fum and Latin fumus, both of which come from Proto-Indo-European *dhuh2mos (smoke), derived from dhewh2 (“to smoke, raise dust”). The word is used to describe any vaporized material, whether a substance or a gas. This word typically refers to a dangerous or strong-smelling vapor.
Ventilated enclosures are an essential tool for the protection of a worker from chemical fumes. They pass contaminated air through a series of filters before releasing the air back into the room. These systems can eliminate high percentages of biological and particulate matter while reducing airborne chemical levels. The effectiveness of these systems can be verified with monitoring protocols.
Whether your lab uses a wide variety of chemicals or only a few, you must have the right fume hood. There are ductless and traditional hoods, each with their own advantages and disadvantages. Ductless hoods are typically less expensive but require constant maintenance. Additionally, their filters are made to protect only a small group of chemicals, and won’t protect your users or samples from a broad range of chemicals found in a typical university lab. These systems also have issues with breakthrough and desorption of vapors. They also require constant attention and disposal of used filters, which is a major expense.
Limitations of fume hoods
While fume hoods can help limit the release of airborne contaminants, they cannot completely eliminate them. It is important to use fume hoods properly by treating them as both work areas and storage cabinets. The materials stored inside should be minimal and should not impede the flow of air. Users should also avoid evaporating chemicals for disposal. It is also important to wear personal protective equipment while working inside a fume hood.
In addition, fume hoods can’t contain explosive materials like perchloric acid. These chemicals tend to build up on surfaces and can explode on contact. In order to prevent this, users should consider using specially designed biological safety cabinets.
Functions of a fume hood
When working in a laboratory, fume hoods are vital tools for ensuring safety and quality air in the working environment. The main function of these devices is to provide a barrier between the workspace and the air outside. A horizontal sash allows for air to flow into the hood, but the sash in a vertical fume hood must be closed to protect the user from airborne contaminants. The sash is usually composed of a series of horizontal window panes that move from side to side. For best results, the sash should be closed when not in use. This will also help to reduce the energy consumption of the fume hood.
Fume hoods are available in different heights and widths and can accommodate one to three operators. They can also be equipped with an enclosed glovebox to protect the operator from harmful substances. The suction speed of a fume hood is directly related to the amount of heat produced by the test items and the rate at which air is changed. An innocuous pollutant produces a minimum of 0.250 m/s of heat, while a pollutant that is a poison or radioactive vapor needs a maximum of 0.40.5 m/s.
Tips for using a fume hood
Properly using a fume hood is essential for laboratory safety. It is important to use it correctly and maintain clean air filters to prevent harmful fumes. Make sure that the filters are clean and never get clogged. In addition, eye protection is necessary while working in fume hoods.
Before using a fume hood, be sure to check its pressure gauge and the signage to ensure proper ventilation. It is also important to keep the sash at an appropriate height for proper containment. Also, avoid placing large apparatus or objects within the fume hood. They can disrupt the air flow and may lead to accidents or death.
When working in a fume hood, the sash must be opened at the correct height for the chemicals being used. This is indicated by the arrows on the hood frame. Also, check the air gauge to see if it is in the correct range. Another important feature of a fume hood is the exhaust fan. This fan is responsible for keeping the fumes contained and avoiding the use of chemicals that could potentially harm a person.
Adding devices to a fume hood
One of the most important safety devices in a fume hood is a performance indicator. These devices provide a visible reading to the hood user. They are usually made up of differential pressure manometers or digital monitoring devices. These devices should be used carefully, because a malfunctioning performance indicator can result in increased exposure to hazardous materials.
Many laboratory apparatuses produce airborne contaminants, which can affect the effectiveness of a fume hood. These operations may require other types of local exhaust ventilation systems, which must be approved by the building facility manager. Another device is a snorkel, which is a long, flexible hose connected to the exhaust system. This device can capture contaminants only very close to the exhaust system’s inlet, usually half the diameter of the exhaust duct.