A fume hood is an enclosed workspace typically found in laboratory settings designed to contain exhaust fumes, vapors, or dust from a particular process. These workspaces are generally equipped with specialized ventilation systems that draw in contaminated air through openings near the top of the hood and suck out unwanted air particles through outlets on the floor. This keeps workers safe by minimizing their exposure to hazardous materials while allowing them to perform experiments or other activities that generate toxic substances.
The application determines construction materials for a fume hood. Construction material possibilities for fume hoods include:
1. Stainless steel
2. Painted aluminum
3. PVDF
4. Polypropylene
5. PFA
How does Fume Hood function?
A fume hood consists of an enclosed work area and two fans, one inside the hood and the other outside. The fan mounted on the exterior sucks in contaminated air through openings at the top of the hood while depositing clean, filtered air back into the lab space. Meanwhile, a second fan inside the workspace draws in contaminated air from below and moves it up through a series of vertical ducts leading to an exhaust outlet on the floor. This helps keep workers safe by ensuring that no hazardous fumes or vapors can escape from within the fume hood.
You may use a fume hood to filter the air and then re-introduce it into the area.
Applications of Fume Hood
A fume hood is typically used to perform experiments or other activities that generate toxic fumes, vapors, or dust. This allows scientists and other workers to conduct these processes without the risk of inhaling dangerous chemicals, powders, or other contaminants. A fume hood's sash allows workers to view and handle things within the enclosure while keeping toxic or volatile chemicals away from their faces.
Fume hoods are essential in many laboratory environments because they help keep workers safe from exposure to harmful substances. They are also frequently used for a wide range of industrial processes and scientific research and development efforts across various industries, including pharmaceuticals, biotechnology, engineering, manufacturing, and more. In addition to laboratory settings and industrial facilities where controlled environments are essential for safety purposes, fume hoods are also commonly found in chemistry classrooms and medical training facilities such as operating rooms and medical laboratories.
When is it recommended to use A Laboratory fume hood?
A fume hood is used whenever there is a potential risk of a worker breathing in hazardous fumes, vapors, dust, or other air contaminants. This typically occurs during experiments or activities such as chemical analysis and synthesis work that can produce toxic substances. For this reason, workers need to be familiar with the chemical properties of any materials they will be working with before using a fume hood to determine if they pose any significant health risks.
A fume hood is advised when working with compounds with a low boiling point or chemicals that produce unpleasant smells. In these cases, it is important to ensure that the workspace remains well-ventilated to minimize exposure and potential health risks. For example, someone working with volatile substances might want to wear a mask or other protective equipment while using a fume hood to prevent fumes from accumulating outside the enclosure. Materials like corrosive acids, asphyxiating gasses, and Irritating vapors and dust require a fume hood to protect workers and keep the surrounding area safe.
Things to consider before buying a fume hood:
There are several key factors to consider when choosing a fume hood for your lab or workspace. Here are some of the most important considerations to keep in mind:
Materials:
Some fume hoods are made from materials like stainless steel or plastic, while others may be constructed from other durable and non-corrosive materials. When deciding which type to use for your lab, it is important to consider the potential hazards and chemicals you will be working with when choosing a material that can best protect against exposure.
The size and capacity:
A fume hood should be sized appropriately for your workspace, considering factors such as the number of workers, materials being handled, and potential hazards or risks. It is also important to ensure that it has sufficient capacity to handle all of the air entering through your exhaust system.
Window orientation:
The orientation of your fume hood's window can greatly impact its performance and efficiency, so it is important to choose one that best suits your needs. Some models may have horizontally-oriented windows, while others may be designed with vertically-oriented windows for optimal airflow and easy access to the work area. In general, more powerful fume hoods tend to have larger windows oriented vertically to facilitate better airflow across the face of the opening.
Standards:
Sometimes a general fume hood does not work for you, and a more powerful one is needed. If your chemical process needs to meet special requirements or standards, you should ensure that any fume hood you purchase is compatible with those standards.
Fume hood safety:
It is important to follow all instructions and guidelines the manufacturer provides regarding use, maintenance, and other important safety considerations to ensure optimal safety when using a fume hood. Always keep your head out of the fume hood while working, and always ensure that the exhaust fan is turned on before starting any potentially hazardous chemical processes.
Keep the sash down while working, as this will help minimize your exposure to potentially harmful fumes. Follow all recommended guidelines for proper ventilation and cleaning, and always use caution when handling any chemicals or other hazardous substances within the fume hood.
Magnehelic gauges can also help you by measuring the flow differential pressure in your fume hood. This is useful for identifying potential problems or areas you could improve. Also, an airflow meter measures the accurate air flow rate through a duct by measuring the pressure difference. This can help you ensure that your fume hood is properly installed and functioning at full capacity, protecting workers from exposure and ensuring safe ventilation within the lab environment.
Face velocity is another important safety factor when using a fume hood. This is determined by measuring the air flow rate across the face of the opening, and it should be at least 50 feet per minute to ensure optimal protection for workers and prevent contaminants from building up within the lab environment. Under most circumstances, a face velocity of 80 to 125 feet per minute is acceptable.
More types of Hoods
Laminar flow hood -A laminar flow hood and a fume hood are used to control the air in a workspace, but they have key differences. A laminar flow hood is typically smaller than a fume hood, as it is most often used to control the environment around one particular piece of equipment or workstation. It mostly protects the product. Laminar flow works by using directional airflow that moves smoothly and at a steady rate over an object rather than moving up through ducts like the exhaust of a fume hood. This allows the worker to use their hands freely during experiments without worrying about them coming into contact with hazardous materials.
In contrast, a fume hood encloses an entire working area so that workers can move freely within it while performing experiments. The exhaust duct of a fume hood also allows air to be pulled up into the workspace, which is important for controlling air quality and preventing dangerous vapors from accumulating.
biosafety cabinet -A biosafety cabinet is typically used for working with biological materials or samples, such as viruses, bacteria, or other microorganisms. It controls airflow around the work area to prevent contamination of the samples while allowing scientists to safely handle them without risk of exposure to hazardous substances.
For this reason, it is commonly found in areas like microbiology labs or veterinary clinics where there is a risk of spreading infectious material. In contrast, a fume hood is used for handling chemicals and other potentially harmful substances that can cause damage if inhaled. This makes it ideal for use in chemistry and pharmaceutical research, where there is a risk of exposure to toxic fumes or powders.
Different Kinds Of Fume Hoods
Several different types of fume hoods are commonly used in laboratory settings. The most common types are:
Variable airflow hoods:
These fume hoods maintain an adjustable airflow that changes according to sash height to maintain a set face velocity. These fume hoods are ideal for general use in a lab, allowing workers to adjust the airflow as needed. They offer better protection than constant air volume models but may be less effective at capturing hazardous fumes or particles that build up close to the sash. These hoods are connected to a monitor where you can see if it's in a "standby operation" or "standard operation" mood. They also have an emergency exhaust button that helps quickly remove contaminants from the lab.
Constant air volume hoods:
These fume hoods maintain a constant airflow by adjusting the fan's speed according to changes in air pressure. They are often used for chemical vapors and toxic fumes that may cause health issues if inhaled at high concentrations. The airflow in a constant air volume hood is changed automatically as the sash is lowered and raised to maintain a fixed air velocity within the fume hood.
Why Use A Fume Hood In The Laboratory?
The primary purpose of a fume hood is to protect lab workers from exposure to toxic fumes or substances. It contains vapors and fumes generated by chemicals or other substances, preventing them from building up in the lab and exposing workers to potential health risks. In addition to protecting lab workers with a sash, fume hoods also protect the integrity of the equipment in the lab by preventing corrosive fumes from damaging sensitive materials.
Some fume hoods also have sensors that automatically shut down airflow in case of a leak or accident. Overall, a fume hood is essential to any modern laboratory setting, providing safety and protection for lab workers and laboratory materials.
A complete guide to the working method of Fume Hood
A fume hood usually works by drawing air into the hood through powerful fans, which help to draw up hazardous chemicals and fumes from your lab. Here is the working process of this device:
Passes Fumes To The Exhaust Area:
As the air passes through the middle of the fume hood, it pushes the hazardous fumes away. The slots and baffles channel the airflow to run parallel to the hood walls. This helps to ensure that the fumes and vapors are carried away from the working area and directed toward the exhaust vents at the back of the fume hood. Through a series of powered fans, filters, and baffles, a fume hood can capture hazardous vapors or fumes generated in laboratory settings and safely discharge them out of the building.
Pulls Air From A Laboratory:
A fume hood contains powerful fans that draw air into the hood through a sash or window at the front. Once drawn in, the contaminated air is filtered and cleaned by a high-efficiency particulate air (HEPA) filter before being released through vents in the back of the fume hood. The amount of air flowing through the fume hood is determined in two ways:
- ●This is the volume of air pulled through the fume hood in a specified time, typically measured in cubic feet per minute (CFM). This is important because it helps ensure that the hood captures a large enough volume of air to remove contaminants effectively. Fume hoods move mass quantities of air, which means the higher the CFM, the more contaminated air can be effectively captured by the hood. If the exhaust rate is high, makeup air needs to be added to ensure that the contaminated air being removed is fully replaced. If not enough makeup air is provided, the laboratory can experience negative pressure, which could cause gasses to be pulled into other areas of the building.
- ●This is the speed at which air moves across a person's face when they are standing in front of the fume hood. This helps ensure that lab workers are not exposed to toxic fumes while working in their laboratories. Face velocity is typically measured in feet per minute (FPM). You can adjust the fume hood sash to change face velocity, depending on the type of chemicals used in the lab. For example, suppose a fume hood is used for highly toxic or volatile substances. In that case, it may be necessary to increase face velocity to ensure that lab workers are not exposed to these materials. It can control the linear rate of air moving with a momentary velocity or the air volume that swirls around in the hood.
Exhausts Fumes Through Ductwork:
The air from the fume hood is sucked in by an exhaust fan installed on the roof, which sends it out via ducts. This ensures that the air is fully filtered before being released into the surrounding environment, protecting lab workers from exposure to potentially hazardous substances or fumes. Various fume hoods are designed for particular applications, such as radioactive, chemical, and biohazardous use. These hoods may have additional exhaust fans, and the ductwork may be sealed to prevent leakage.
Overall, a fume hood is essential to any modern laboratory setting, providing safety and protection for lab workers and laboratory materials. Whether using highly toxic chemicals or simply working with everyday substances like solvents or oils, a fume hood can help ensure that your work environment is safe and controlled. So if you are looking for reliable protection in your next lab project, consider investing in a high-quality fume hood today!