What Is a Fume Hood & How Does It Work?

What Is a Fume Hood & How Does It Work?

Laboratory fume hoods create a safe working environment for researchers and scientists. These enclosed workspaces are designed to contain and exhaust hazardous fumes, vapors, and dust generated during experiments, protecting the user and the laboratory environment.

One of the primary functions of a laboratory fume hood is to prevent chemical exposure to researchers. It acts as a barrier between hazardous substances and users, allowing them to conduct experiments without direct contact with potentially harmful materials. Additionally, fume hoods maintain a controlled and clean laboratory atmosphere, which is crucial for accurate experimental outcomes.

Types of Hazardous Materials Handled

Laboratory fume hoods are engineered to handle a wide range of hazardous materials. These include corrosive chemicals, toxic fumes, particulates, and even substances like perchloric acid, which require specialized hoods due to their unique properties. 

By providing a contained space for working with such materials, fume hoods are essential for conducting experiments that involve potentially dangerous compounds.

Components of a Laboratory Fume Hood

To maximize the effectiveness of a laboratory fume hood, it's crucial to understand its various components and how they contribute to its functionality.

Work Area

The work area of a fume hood is the interior space where experiments are conducted. It is typically lined with a chemical-resistant surface, making it easy to clean and resistant to corrosive substances. The dimensions of the work area can vary depending on the specific requirements of the laboratory.


The sash is a movable transparent panel located at the front of the hood. It serves as a protective barrier, preventing contaminants from escaping while allowing the user to access the work area. Proper adjustment of the sash height is crucial for maintaining the desired airflow and containment levels.


Baffles are vertical panels or structures within the fume hood that help control the airflow patterns. They disrupt the straight-line airflow, creating turbulence that aids in capturing and containing contaminants. Well-designed baffles contribute significantly to the hood's overall performance.

Airflow System

The airflow system moves air into and out of the fume hood. It ensures that any potentially harmful substances released within the hood are effectively captured and exhausted, preventing them from accumulating in the laboratory environment.

Exhaust System

The exhaust system is connected to the fume hood. It directs the contaminated air to the external environment, often through a ductwork system. It plays a crucial role in maintaining a safe and clean laboratory atmosphere.

Filtration System

In the case of ductless fume hoods, a filtration system removes contaminants from the air before recirculating them back into the laboratory. This system typically includes HEPA filters to ensure exhaust air meets safety standards.

How Laboratory Fume Hoods Work

Understanding the fundamental principles of airflow is essential for optimizing the performance of a laboratory fume hood.

Airflow Principles

Laboratory fume hoods operate on the principle of inward airflow. Air is drawn into the hood through the open front, creating a barrier that prevents hazardous fumes from escaping into the laboratory.

Face Velocity & Its Significance

Face velocity refers to the speed at which air is drawn into the fume hood's work area. It is a critical parameter that influences the containment effectiveness of the hood. Maintaining the appropriate face velocity ensures that contaminants are efficiently captured and directed toward the exhaust system.

Contaminant Capture & Dispersion

Baffles and airflow patterns within the fume hood work in tandem to capture and contain contaminants. The turbulence created by the baffles disrupts the natural dispersion of fumes, preventing them from escaping into the laboratory environment.

Variable Air Volume (VAV) vs. Constant Air Volume (CAV)

Fume hoods can employ either Variable Air Volume (VAV) or Constant Air Volume (CAV) systems. VAV systems adjust the airflow based on the sash position, optimizing containment and energy efficiency. 

CAV systems maintain a constant airflow regardless of sash position. Choosing between these systems depends on specific laboratory requirements and energy considerations.

Types of Laboratory Fume Hoods

Laboratory fume hoods come in various configurations, each tailored to specific applications and safety requirements.

Ducted Fume Hoods

Ducted fume hoods are connected to an external exhaust system through ductwork. They effectively remove hazardous fumes and direct them safely out of the laboratory. These hoods are versatile and suitable for various applications involving volatile chemicals.

Ductless Fume Hoods

Ductless fume hoods utilize filtration systems to remove contaminants from the air before recirculating them back into the laboratory. They offer a cost-effective and environmentally friendly alternative for laboratories where ductwork installation is impractical. However, they are best suited for applications involving non-hazardous or low levels of volatile chemicals.

Biosafety Cabinets

While similar in appearance to fume hoods, biosafety cabinets are designed to provide a controlled environment for working with biological materials. They offer a high level of protection for both the user and the surrounding environment, preventing the release of airborne pathogens.

Glove Boxes

Glove boxes are enclosed workspaces that allow researchers to handle hazardous materials in an isolated environment. They feature built-in gloves for manual dexterity and are particularly useful when working with highly toxic or sensitive substances.

Selecting the Right Fume Hood

Choosing the appropriate fume hood is a critical decision that hinges on various factors related to the laboratory's specific needs.

Assessing Lab Needs & Hazards

Before selecting a fume hood, it's essential to thoroughly assess the types of experiments and materials that will be handled. Consider the potential hazards and ensure the chosen hood is designed to handle them effectively.

Understanding Airflow Requirements

Different experiments require varying levels of containment and ventilation. Ensure that the selected fume hood can achieve the necessary face velocity and airflow patterns to handle the materials involved safely.

Considering Specialized Hoods

Certain experiments, such as those involving perchloric acid, may necessitate specialized fume hoods designed to handle the unique properties of these substances. It's crucial to choose a hood that is specifically engineered for the task at hand.

Ergonomics & User Comfort

A well-designed fume hood should prioritize safety and provide a comfortable and ergonomic workspace for researchers. Consider factors like sash height adjustment and ease of access when selecting a fume hood.

Installation & Maintenance

Proper installation and regular maintenance are vital for ensuring a laboratory fume hood's continued effectiveness and safety.

Proper Hood Placement

The location of the fume hood within the laboratory should be carefully chosen to optimize airflow patterns and minimize potential interferences. It should also allow for easy access and operation.

Connection to Exhaust System & Ductwork

For ducted fume hoods, the connection to the external exhaust system and ductwork must be expertly configured to ensure the efficient removal of contaminants. Proper sealing and airflow balancing are crucial aspects of this installation process.

Periodic Inspections & Testing

Regular inspections and testing of the fume hood are essential to promptly identify and address any potential issues. This includes checking for leaks, verifying airflow, and ensuring safety features function correctly.

Maintenance Best Practices

Following manufacturer-recommended maintenance schedules and practices is essential for prolonging the lifespan of the fume hood and preserving its safety features. This may include filter replacements, sash repairs, and airflow adjustments.

Safety & Regulations

Adhering to safety guidelines and regulations is paramount when working with laboratory fume hoods.

EHS Guidelines & Compliance

Environmental Health and Safety (EHS) guidelines provide a framework for the safe use of laboratory fume hoods. Laboratories must stay compliant with these regulations to ensure the well-being of personnel and maintain a secure work environment.

Personal Protective Equipment (PPE) Requirements

In addition to using a fume hood, researchers must don appropriate personal protective equipment (PPE) to minimize exposure to hazardous materials further. This may include lab coats, gloves, safety goggles, and respiratory protection.

Handling Hazardous Chemicals Safely within the Hood

Proper techniques for handling hazardous chemicals within the fume hood are crucial. This includes avoiding sudden movements that may lead to splashes and ensuring that containers are tightly sealed to prevent the release of vapors.

Major Manufacturers & Brands

Several reputable manufacturers specialize in producing high-quality laboratory fume hoods.

Overview of Leading Manufacturers

Companies like Labconco, Thermo Fisher Scientific, and Erlab are renowned for their innovative and reliable fume hood solutions. They offer a range of options tailored to different laboratory settings and requirements.

Notable Features & Offerings

Each manufacturer may have unique features that set their products apart. This could include advanced airflow control systems, ergonomic designs, or specialized hoods for specific applications.

Conclusion & Recap

Laboratory fume hoods are indispensable for safeguarding researchers and maintaining a secure laboratory environment. Laboratories can ensure a safe and productive workspace by understanding their components, functions, and the importance of proper selection and maintenance.

Staying updated on safety regulations and being aware of emerging trends in fume hood technology allows for continuous improvement in laboratory practices.

Ready to Elevate Your Lab's Safety and Efficiency?

Leasing a state-of-the-art fume hood with Excedr could be the game-changer your laboratory needs. Here's why:

  • Streamlined budgets enhance capabilities: Leasing allows you to access top-of-the-line fume hoods without a hefty upfront investment. This means you can allocate your budget towards critical research endeavors and other essential equipment.
  • Stay ahead of technological advances: In the fast-evolving world of laboratory equipment, having the latest innovations at your fingertips is a competitive advantage. Leasing ensures you can easily upgrade to the most advanced fume hood solutions, keeping your lab at the forefront of scientific progress.
  • Tailored solutions for your unique needs: Excedr offers flexible leasing options that can be customized to your specific requirements. Whether you need a ducted fume hood for comprehensive ventilation or a ductless solution for specialized applications, we have you covered.
  • Hassle-free maintenance and support: Leasing with Excedr includes comprehensive maintenance and support services. Enjoy peace of mind knowing that your fume hood is operating at peak efficiency, allowing your researchers to focus on what matters most.

Want to take your laboratory to the next level? Contact us today and explore our leasing options for top-of-the-line fume hoods, biosafety cabinets, and other essential safety equipment. Elevate your research environment and drive scientific excellence with Excedr.