With the world still struggling with COVID-19, it’s important to know about the safety devices in labs. When it comes to laboratory safety, two types of units are absolutely essential. They are fume hoods and biosafety cabinets (BSCs).

Both have ventilation systems to keep lab personnel safe. Therefore, it is easy to confuse the two. Additionally, both require regular testing and certification services.

So, what’s the difference between them? And which one is right for your lab? In this blog post, we’ll take a closer look at both fume hoods and BSCs.

What Type of Protection Do These Units Offer

Designed to protect lab personnel, fume hoods prevent exposure to hazardous fumes, vapors, and dust. A fume hood is essentially a large, enclosed space with a ventilation system. The system pulls air into the fume hood and exhausts it outside the building.

BSCs, on the other hand, protect lab personnel from exposure to pathogens and other biohazards. Unlike fume hoods, they do not protect you against fuming chemicals.

Key takeaway: Fume hoods provide protection from fumes. BSCs provide protection from particulates.

What Type of Airflow Do They Have?

Airflow is the key to how these units function. Each type of hood has the right airflow to handle the lab hazard for which it is designed safely.

Fume Hood Air Flow:

The fume hood has negative airflow. This means that it pulls the air into the fume hood and then gets exhausted out of the building. This type of airflow is important for fume-type hazards because it prevents chemicals from escaping into the lab.

BSC Air Flow:

The BSC has positive airflow. This means that it pushes HEPA filtered air into the cabinet and away from the user. This is important for particulate-type hazards because it protects the user from exposure to pathogens or other biohazards.

Key takeaway: Fume hoods have negative airflow while BSCs have positive airflow.

What Are They Used For?

Depending on the work in the lab, you will need to use a fume hood or BSC for safety.

Fume Hood Applications:

Fume hoods protect the user. Primarily, they are found in research labs, educational facilities, and forensic labs.

Fume hoods should be used when working with any chemical fumes. This includes strong acids, bases, and solvents. Additionally, radioactive materials can create fumes, so a fume hood is necessary.

Typical Fume Hood Applications:

  1. Chemical fumes and spatter
  2. Toxic gases or volatile materials
  3. Radioactive fumes
  4. Aerosols, carcinogens, and flammables

BSC Applications:

In addition to protecting the user, BSCs also protect the product/process and the environment.

Typically, BSCs are found in biomedical research laboratories. For instance: tissue culture work or handling of pathogens. Additionally, they are found in clinical settings for the preparation of medications or other treatments that involve hazardous materials.

While they are a type of fume hood, BSCs have added layers of protection to reduce the risk of lab contamination. They ensure containment for the surrounding areas. Depending on the class of the cabinet, they are suitable for use with materials that require Biosafety Levels (BSL) 1, 2, or 3. The type of BSC you need will depend on the level of containment required for the task at hand. Class I and II cabinets provide primary containment, while Class III cabinets provide total containment.

Typical BSC Applications:

  1. Pathogens
  2. Tissue culture work
  3. Hazardous chemicals

Key Takeaway: Fume hoods are used for chemical fume capture, while BSCs are used for pathogen handling.

Testing & Certification: Fume Hood vs. BSC

Testing and certification are performed to comply with regulations and standards of OSHA, ASHRAE, and more. But what are the differences in the two units?

Fume Hood Testing & Certification:

  1. Conducted annually, at minimum
  2. Redo the test after making changes or repairs to the equipment
  3. Follow ASHRAE-110 testing protocols

BSC Testing & Certification:

  1. Conducted annually, unless used in a CGMP environment where it needs to be conducted semiannually
  2. Redo test after maintenance, including simple replacement of HEPA filters
  3. Meet NSF-49 guidelines and manufacturer specs



A fume hood is a type of ventilation system that is used in order to protect the user from exposure to hazardous or poisonous fumes. A bio safety cabinet, on the other hand, is a type of enclosed workspace that is used in order to protect both the user and the environment from exposure to hazardous materials. Both fume hoods and bio safety cabinets are important pieces of equipment in a laboratory setting, and it is important to know the difference between the two in order to ensure that you are using the right type of equipment for your specific needs.

Feature Fume Hood Bio-Safety Cabinet
Protection Chemical contaminants Biological contaminants
Hazard Type Chemicals: Toxic, Reactive, Aerosols, Carcinogens, and other materials Biologicals: Infectious micro-organisms and hazardous particulates
Airflow Negative pressure only
Contaminants are led away from the user into the ducted fume hood. Then, it exhausts to the outside environment. In ductless fume hoods, contaminated air is filtered and recirculated into the same room.
Negative or Positive Pressure
Prevent contamination of the sample, protect the user, and environment. Contaminants must be filtered through HEPA before release. Filtered air is released in the same room or is exhausted outside.
Filtration None in ducted Fume Hoods; Activated carbon in ductless Fume Hoods HEPA Filter in all types of Bio-Safety Cabinets
International Standards ANSI/ASHRAE 110



EN 12469

PPE Recommended Must Wear
Lab tech working under fume hood