Chemical fume hood

A fume hood has a work surface, side and back walls, and a front opening with a movable sash. Room air flows in through the opening and carries contaminants to the exhaust duct at the rear. The sash provides a physical shield against splashes and small reactions, and it should be kept as low as practical during work.

Correct use is essential. Work should be carried out well inside the hood rather than near the front edge, equipment should be kept clear of the rear slots, and the amount of clutter should be small so that air can flow. Fast movements, people walking past and open windows can disturb the airflow and pull contaminants out toward the user.

Hoods need to be checked. Most have an airflow monitor or gauge, and facilities usually test face velocity and performance on a schedule. Hoods are designed for chemical work, not for storing bottles, and they do not protect against everything. Some processes, such as those involving perchloric acid or radioactive materials, require specially designed hoods.

A fume hood is an example of Engineering controls and is more protective than relying on Personal protective equipment (PPE) alone. It is different from Local exhaust ventilation (LEV) in industrial processes and from a biosafety cabinet. Procedures that release volatile or toxic materials, such as heating solvents, should be done inside it, following guidance on the SDS.