Fume Hood

Overview

The fume hood is a ventilated enclosure that protects laboratory workers from inhaling toxic vapors, fumes, and aerosols by drawing contaminated air away from the operator and exhausting it outside the building. It is the primary engineering control for chemical handling. The hood works by maintaining an inward airflow at the open sash, the face velocity, that is fast enough to capture contaminants but not so fast that it creates turbulence pulling them back out.

Construction

The Superstructure is a welded steel frame clad in chemical-resistant epoxy or phenolic liner walls, with a dished epoxy worktop, a cup sink, and an adjustable Baffle Panel Assembly panel set whose slots shape airflow evenly across the work zone. A sealed LED Interior Light Fixture illuminates the chamber from behind safety glass so the lamp never contacts fumes.

The Sash Assembly is a vertical-rising tempered-glass pane on guided tracks, balanced by a cable-and-counterweight system so it stays at any height, with a stop that limits the open area to the rated face velocity. The Base Cabinet supports the superstructure and houses service plumbing.

How it works

Air entering at the sash sweeps across the work surface, through the baffle slots, into the Exhaust Connection plenum, and out a round collar to the building stack. The Exhaust Blower, a direct-drive centrifugal wheel in a coated scroll housing, provides the suction; an in-line Exhaust Damper balances and throttles the flow.

Containment is verified continuously by the Airflow Monitor & Controller, a thermal-anemometer sensor at the sash plane feeding a controller that displays face velocity and triggers an audible and visual alarm if flow drops below the safe threshold. Plumbed Service Fixtures bring gas, water, and vacuum to gooseneck fixtures inside the hood, with GFCI receptacles mounted on the face so electrical connections stay outside the contaminated zone.