What Is a Ductless (Filtered) Fume Hood?

1. What Is a Ductless Fume Hood?

A ductless fume hood, also known as a filtered fume hood, is a laboratory safety device that uses a recirculating air purification system. Unlike traditional fume hoods, it does not require external ductwork. Instead, harmful chemical vapors and particulates are captured by activated carbon filters and HEPA filters, and the cleaned air is then safely released back into the room. It is a flexible, energy-efficient air purification solution for modern laboratories.

2. How Does a Ductless Fume Hood Work?

The working principle of a ductless fume hood follows a Capture → Filtration → Recirculation process:

(1) Contaminated air inside the hood is drawn into the filtration system.

(2) The air passes through multiple filters:

• Activated carbon for chemical vapors

• HEPA filters for particulates and aerosols

(3) Purified air is released back into the laboratory.

This ensures safe operation and prevents harmful substances from spreading.

3. How to Use a Ductless Fume Hood

Operating a ductless fume hood is simple and user-friendly:

(1) Turn on the power and fan, and check the airflow reading.

(2) Place chemical containers in the center of the work area.

(3) Keep the sash at the recommended height for safe containment.

(4) Perform weighing, mixing, or sample preparation inside the hood.

(5) Allow the unit to run for 2–5 minutes after finishing your work.

(6) Replace filters regularly according to the manufacturer’s instructions.

4. Application Areas of Ductless Fume Hoods

Ductless fume hoods are ideal for laboratories that require flexibility and clean air, such as:

• Chemical analysis laboratories

• Pharmaceutical and biotechnology R&D

• Cosmetics and food product development

• University and educational labs

• Environmental testing centers

• Electronics manufacturing facilities

• Laboratories located in office buildings or rental spaces

• Temporary or mobile laboratories