Fume hoods are critical safety devices in any laboratory where hazardous chemicals, vapors, or fumes are present. When used correctly, fume hoods help protect lab personnel by drawing harmful vapors away from the breathing zone and safely expelling them outside. However, improper use of fume hoods reduces their effectiveness and could expose researchers to dangerous substances. To maximize safety, follow these five essential steps when working with a fume hood.

1. Place Equipment and Reactions Toward the Back of the Hood

For optimal airflow and fume capture, always place your equipment, chemicals, and reactions as far back in the fume hood as possible—at least six inches from the front edge. Keeping materials away from the opening helps ensure fumes are properly drawn into the hood and not back into the lab environment.

Why Placement Matters

Obstructions near the front of the hood can disrupt airflow, causing fumes to escape into the lab. By positioning your work deep inside the hood, you help maintain smooth airflow and improve overall safety.

2. Turn On the Fume Hood Light

Before starting any work, turn on the fume hood light using the switch located near the electrical outlets on the exterior panel of the hood. Good lighting improves visibility, allowing you to work safely and spot potential spills or hazards more easily.

Safety Tip

Well-lit workspaces not only enhance precision but also reduce errors when handling hazardous chemicals.

3. Maintain Proper Sash Height

The fume hood sash serves as a protective barrier between you and hazardous substances. Most modern fume hoods have a built-in automatic stop to ensure the sash remains at the recommended operating height—usually around 18 inches.

Best Practices for Sash Use

• Keep the sash at the recommended height during use.
• Only raise the sash briefly to place or remove materials.
• Always keep your head and upper body outside the hood. Never lean inside the fume hood, as this exposes you to harmful vapors.
• If the automatic stop height feels too high to provide adequate protection, you may lower the sash slightly to protect your face and body.

4. Clean Up Immediately After Spills

If a spill or splash occurs inside the fume hood, immediately clean both the affected area and the inside surface of the glass sash. Proper cleanup ensures that hazardous residues don’t accumulate over time, reducing the risk of cross-contamination or unexpected chemical reactions.

Quick Response Guidelines

• Use appropriate spill kits or absorbent materials.
• Cleanup materials should be disposed of according to lab waste disposal procedures.
• Record the incident if required by your lab’s safety protocols.

5. Lower the Sash After Use

Once your work is complete, lower the sash to the height specified on the safety sticker located on the side of the fume hood. Closing the sash conserves energy and ensures the hood maintains proper negative pressure when not in active use.

Energy Efficiency and Safety

• Lowering the sash reduces the amount of conditioned air drawn into the hood, conserving energy.
• A closed sash acts as an additional safety barrier in case of accidental releases.

Final Thoughts

Proper fume hood use is one of the most effective ways to protect yourself and your colleagues from exposure to hazardous fumes and vapors. Following these five steps ensures your fume hood functions as designed, contributing to a safer and more compliant laboratory environment.

Frequently Asked Questions (FAQ)

1. Why is it important to place equipment at the back of the fume hood?

Placing equipment at least six inches from the front edge helps maintain proper airflow, ensuring fumes are effectively captured and directed away from the lab environment.

2. What should I do if the fume hood sash is stuck?

If the sash is stuck or doesn’t stay at the recommended height, report the issue immediately to your lab manager or facilities team to ensure the hood can be repaired before further use.

3. Can I store chemicals in a fume hood?

Fume hoods should not be used for long-term chemical storage, as stored materials can obstruct airflow and reduce the hood’s effectiveness. Use designated chemical storage cabinets instead.

4. How often should fume hoods be inspected?

Fume hoods should undergo regular inspections (at least annually) to check airflow, sash operation, and overall condition. Always check for a valid inspection sticker before use.