A Beginner’s Guide to Working with Laboratory Fume Hoods

As a new operator, there is a lot to study and understand in a laboratory. One of the things you need to learn about is laboratory fume hood. This post will take you through everything you need to know about a fume hood, including how to operate it and its key components.

What is a Fume Hood?

A lab fume hood is a ventilation system that exhausts gases, chemical fumes, vapors, aerosols, mist and dust from the laboratory. A fume hood also functions as a physical barrier between chemical reactions and the operator, offering protection against inhalations, spills, fires and runaway reactions.

Types of Laboratory Fume Ho

There is a wide range of options when it comes to selecting hoods from a fume hood manufacturer.

The common types of exhaust fume hoods include;

• Distillation fume hood. These hoods have large working heights. The height allows for installation of tall distillation equipment in the work chamber.
• Radioisotope fume hood. Lab technicians who handle large amounts of radioactive materials can use radioisotope fume hoods for protection. These hoods are specifically designed for radioactive materials. Their interior consists of stainless steel with coatings to help in decontamination.
• Acid digestion fume hood. These hoods have special liners made using acid-resistant materials like unplasticized PVC. Their sashes are made using polycarbonate materials to resist corrosion due to hydrofluoric acid.
• Ductless fume hood. These hoods use activated carbon to absorb chemical fumes and vapors.
• Bench top fume hood. They are designed to offer protection against almost all chemicals used in the laboratory.

Components of a Fume Hood

There are seven main components of lab fume hoods. These are;

• Hood Body
• Sash
• Baffles
• Face
• Exhaust Plenum
• Work Surface
• Airfoil

The hood body is the visible surface of the hood that houses the hazardous vapors and gases.

The baffles are the adjustable partitions used to create an opening at the back of the hood body. They serve to keep a uniform flow of air across the hood, enhancing the efficiency of the equipment in the process.

The sash is the sliding door used to adjust the front opening of the hood. It helps control airflow and increases the rate at which the hood captures contaminants. The sash can either be vertical, horizontal or a combination of horizontal and vertical.

The airfoil streamlines airflow in the hood and prevents turbulent eddies from building up. The exhaust plenum distributes air evenly across the face of the hood. The face is the imaginary area between the sash and work surface.

How to Use a Fume Hood Effectively

When using a fume hood, adequate preparation and planning are important. You should know the standard operating procedures of the equipment and maintain them throughout.

Here are some guidelines you need to observe.

• Make sure the exhaust is in good working condition before you begin any experiment. Examine the baffles and see if there are any obstructions. If the hood has an airflow monitor, check to see if it is at the correct level.
• Keep your face outside the plane of the hood to limit chemical exposure.
• Use appropriate protective gear, like splash goggles, lab coat and gloves. Such gear will protect you in case of dangerous spills and fire.
• Always keep the hood closed when it is not in use.
• Make sure the sash is closed to save energy.
• Terminate operations immediately if you suspect a malfunction or when the airflow alarm goes off.
• Do not make quick motions when using the hood, like suddenly removing or placing items in the hood. Doing so will cause air disturbance and reduce the effectiveness of the equipment.
• Read the instructions from the fume hood manufacturer carefully to avoid making mistakes.

Just like any other lab equipment, exhaust fume hoods will serve you better if you understand how they work. The items discussed above will help you get started with your lab fume hood in a safer and easier manner.