A fume hood (also called a chemical fume hood) is a type of ventilation system used in laboratories to limit exposure to hazardous or toxic fumes, vapors, or dust.

In simple terms:

It's a protective cabinet with a glass front (sash) that pulls air away from the person working and vents harmful substances outside or filters them.

Key Features:

• Airflow: It draws air in from the lab and out through a duct, keeping hazardous vapors away from you.
• Sash (Glass Window): Protects you from splashes and acts as a shield.
• Work Surface: Inside the hood is where you place your equipment and perform experiments.
• Exhaust System: Sends the contaminated air outside the building or through filters.

Why it's used:

• Protects you from breathing harmful chemicals.
• Prevents fires or explosions from volatile substances.
• Helps contain spills or reactions.

Two Main Types:

• Ducted Fume Hood: Ventilation air is expelled outside the building.
• Ductless Fume Hood: Uses filters to clean the air and recirculates it back into the room.

How to Use a Fume Hood in a Lab

Check that it's working

• Look for the airflow monitor or gauge — make sure it’s in the safe zone (usually green).
• You can also do a quick test: hold a tissue at the opening to see if it gets pulled inward.

Set up your equipment properly

• Place your materials at least 6 inches (15 cm) inside the hood, away from the sash opening.
• Don’t block the air slots or vents at the back — that disrupts airflow.
• Keep it organized: fewer items = better airflow and safety.

Lower the sash

• Keep the sash (glass window) as low as possible while still allowing you to work comfortably.
• It acts as a physical barrier in case of a splash, fire, or explosion.

Turn on the fan (if needed)

• Some fume hoods have a manual on/off switch. Others run continuously.

Work carefully

• Avoid rapid movements — they disturb airflow.
• Don’t lean your head or body inside the hood.

Dispose of waste properly

• Use appropriate containers and follow your laboratory protocol for hazardous waste.

When finished

• Remove your materials.
• Close the sash completely.
• Leave the fan on if instructed by your lab (some need time to clear out remaining vapors).