Robert M. Rioux & William A. Elliott, Pennsylvania State University, University Park, PA

Fume hoods and laminar flow cabinets are engineering controls that operate under similar principles. Both use a constant flow of air to prevent contamination of the laboratory environment and its inhabitants. Fume hoods prevent hazardous substances from exiting the hood workspace, whereas laminar flow cabinets prevent contaminants from entering the cabinet workspace.

Fume hoods are ventilation systems designed to minimize exposure to hazardous vapors, fumes, and particles. A constant flow of air is drawn into the hood opening, limiting the escape of vapors, fumes, and particles, and then is pulled out through the exhaust. Laminar flow cabinets are used to maintain a sterile/clean environment by constantly flowing high-efficiency particulate arrestance (HEPA)-filtered air outwards, minimizing contaminated air entering the cabinet workspace. The HEPA-filtered air reduces the opportunity for harmful chemicals or particles from entering the laboratory. A HEPA filter removes 99.97% or greater of 0.3 µm particles.

1. Fume hoods

1. Uses
   1. Fume hoods are used when a material generates harmful vapors, fumes, or airborne particles, such as fine silica powders, or volatile carcinogens, such as benzene.
2. Operation
   1. Air is drawn in though the opening face of the hood, where the user works, and out through the exhaust. The constant flow of air inwards towards the face prevents hazardous vapors, fumes, and particles from escaping out through the hood opening, keeping the user and other l

Fume hoods and laminar flow cabinets are useful tools in the laboratory to prevent harm from hazardous materials and to keep a clean working space when using sensitive materials. However, fume hoods and laminar flow cabinets are only effective when used properly. Following simple operating guidelines and performing regular maintenance, fume hoods and laminar flow cabinets can be effective tools in the laboratory.

1. American National Standard for Laboratory Ventilation," American National Standards Institute, Inc./ American Industrial Hygiene Association, ANSI/AIHA Z9.5, 2012.