8384062994
accumax105@gmail.com
8384062994
accumax105@gmail.com
Fri Jul 05, 2024
Fume Cabinet
What is a fume hood? A fume hood is an enclosure that safely contains and ventilates hazardous fumes, vapors, gases and dust generated by chemical processes performed in the fume hood. Sometimes called a chemical hood or a lab hood, a fume hood protects workers from inhalation of hazardous substances.The clear sliding window on a fume hood, called the sash, also shields workers from spills and splashes that may occur in the chemical fume hood.Fume hoods are the workhorse of laboratory exhaust systems and are the most widely used approach for local ventilation.
Using a blower, a fume hood draws air into the enclosure away from the user. Through a facility exhaust system, the fume hood then filters and vents the air outside. As an alternative, the air can be filtered in a fume hood to eliminate harmful fumes before being recirculated into the space. The majority of fume hoods come with gauges or alarms that alert users to possible fume exposure and inadequate airflow.
Fume hoods allow lab employees to work with potentially dangerous chemicals while minimizing the risk of exposure to toxic fumes. The sash (window) on a chemical hood allows the worker to view and manipulate objects within the enclosure while keeping fumes from toxic or volatile chemicals away from the worker’s face.
Industries that use fume hoods include:
What kinds of risks can an operator be shielded from by a fume hood?
When is a fume hood used? It is generally recommended to employ a laboratory fume hood for handling hazardous materials. A fume hood or other ventilation device is required if the Safety Data Sheet (SDS) for the chemical you intend to use contains warnings such as "Toxic by inhalation" or "Do not breathe dust, fumes, or vapours."Using a fume hood is advised when handling substances that release offensive odors or have a low boiling point.
Types of materials that should be used inside a chemistry fume hood include:
What distinguishes a Laminar Flow Hood from a Fume Hood?
Laminar flow hoods and chemical fume hoods are not the same thing, despite common confusion between the two. Both employ airflow as a defense mechanism, but the target of defense is different: Laminar flow hoods shield the product, but chemical fume hoods shield the workers.To shield workers from dangerous vapors, air is drawn away from them under a fume hood. In contrast, filtered air is blasted out of a laminar flow hood, also known as a clean bench. Particulate particles cannot contaminate a product, such as a semiconductor wafer or biological sample, thanks to the smooth, non-turbulent airflow.
What distinguishes a Fume Hood from a Biosafety Cabinet?
Another type of lab equipment that is commonly mistaken for fume hoods is Biosafety Cabinets. Both rely on airflow for defense, yet the threats that each target are different: Biosafety cabinets guard against diseases and biological agents, whereas fume hoods shield against chemical fumes and vapors.HEPA filters are used in biosafety cabinets, also known as biological safety cabinets or BSCs, to eliminate pathogenic microorganisms from exhaust air. A biosafety cabinet may also use HEPA filters on intake air to shield the product from contamination, depending on the class and kind. In contrast, exhaust air released outdoors through a fume hood often does not utilize HEPA filtering.
Fume hood buying tips: What to look for in a fume hood
Size: A basic starting point when shopping for and specifying a fume hood is size. What size is the working area required for your application? What size is the available space on the factory floor or the laboratory for a fume hood? Best Technology builds custom fume hoods, so even if your size requirements are unusual, we can build a fume hood to fit your space.
Materials: Specific materials are needed for containment in certain chemistries. For instance, large concentrations of highly corrosive acids may call for a fume hood made of polypropylene rather than stainless steel for improved corrosion resistance. To prevent etching of a glass window caused by hydrofluoric acid, polycarbonate is the recommended material for the sash. It's essential to know the anticipated chemistry that will be used in the fume hood to guarantee years of dependable operation.
Window orientation: Certain fume hoods have a horizontal sliding glass that restricts the operator's access to the fume hood's operating area. To give users additional working space inside the fume hood, look for a vertically movable window, or sash. Fume hoods with counterbalanced, vertically movable glass are available from Best Technology.
Fume Hood for Semiconductor Wafer Chemical Processing
Fume hoods with ducting
The ventilation system of the building is what powers a ducted fume hood, which uses ducts to vent exhaust air outside. The fume hood can run silently because the fan or blower is usually mounted on the building's roof. The ductwork for a fume hood should be isolated from the rest of the building's ventilation ducts to avoid the recirculation of contaminated air.
Steer clear of ductless Fume Hoods. A blower on a ductless fume hood, also known as a recirculating fume hood, draws contaminated air through a HEPA filter before recirculating it back into the space. The operator must make sure the right filter is used for safety because the type of filter needed varies based on the chemical. For safety, filters must also be changed on a regular basis.Ductless fume hoods save money by eliminating the need for ductwork installation up front, but they increase noise, need more maintenance, and put workers and other equipment at risk of chemical exposure. These factors have led several American research colleges to outlaw the use of ductless fume hoods.
Safety of Fume Hoods
Keep your head out of the fume hood: To make sure that a fume hood's safety features are not circumvented, user behavior is essential. The head should never be placed inside a fume hood—only the hands and arms should.
Sash down: The user must keep the sash down in order to benefit from the fume hood's safety features. The user is less likely to be exposed to chemicals when the sash is lowered. Many fume hoods specify a maximum fume hood sash height to maintain safe exposure levels.
Safety equipment for fume hoods
The majority of fume hoods come with a magnetic gauge or an airflow meter for checking the amount of airflow inside the enclosure. These tools use significantly different methods to verify airflow.
• The difference in air pressure between the fume hood's inside and exterior is measured using a magnethelic gauge.
• The real airflow rate within the fume hood is measured using an airflow meter.
The operator can verify if the exhaust system is operating with these instruments. Many organizations have emergency protocols for managing potentially harmful fumes in case the air isn't draining as planned.
Face velocity is another metric used by fume hoods to assess exhaust power. The aperture on a fume hood where air enters is called the face. Therefore, face velocity, expressed in feet per minute (fpm), is the air's velocity when it enters the fume hood. Face velocities between 80 and 125 fpm are usually regarded as appropriate.
Tips for operating a Fume Hood
Energy expenditures can be decreased by keeping the sash closed when not in use and as low as feasible. Reducing the amount of exhaust lessens the strain on the building's HVAC system because the fume hood expels conditioned air, which may be heated or cooled depending on the local environment. Keep in mind that the position of the sash might alter the enclosure's air velocity; a closed sash may have enough increased airflow to disrupt sensitive components or equipment. To achieve the ideal balance for you, the blower speed may need to be adjusted a little.
Learn from a Fume Hood specialist
Are you prepared to begin working on your project? Look to Best Technology for professional assistance with your wet chemical process systems. We have application engineers on hand to respond to your inquiries and provide you with the ideal fume hood. For additional details and a free proposal, get in touch with us.