Fume Hood Technology—Glossary of Terms

Airfoil:

Shaped or streamlined member at hood entrance designed to enhance movement of air into the hood.

Air Volume:

Rate of airflow, normally expressed in cubic feet per minute (CFM).

ASHRAE:

American Society of Heating, Refrigerating, and Air Conditioning Engineers, a professional organization that sets industry standards for fume hood testing procedures.

Auxiliary Air:

Supply or makeup air delivered external to the chamber of a fume hood to reduce air consumption.

Baffle:

Panels located across back of hood interior, which control pattern of air moving through the hood.

Blower:

Air moving device (or fan) consisting of motor, impeller, and scroll.

Bypass:

Compensating opening that helps maintain constant volume exhaust from fume hood, regardless of sash position.

Canopy Hood:

Ceiling or wall suspended ventilating device for noncritical use with heat, water vapor, odors, etc.

CFM:

Cubic Feet Per Minute, a unit of measurement of air volume.

Combination Sash:

Horizontal panels in a vertically rising frame; see sash.

Constant Volume:

Type of fume hood exhaust system that exhausts the same volume of air, regardless of sash position.

Containment:

Extent to which fumes are confined within the hood compartment.

Damper:

Device installed in duct to control air volume.

Demonstration Hood:

Fume hood with glass panels on two or three sides to improve visibility for demonstrating experiments in a classroom setting.

Exhaust Volume/Parameters:

Quantity of air exhausted by the fume hood; quantity of air required to maintain desired face velocity, expressed in cubic feet per minute (CFM).

Face Velocity:

Speed of air moving into the fume hood through the face opening (through the sash), measured in feet per minute (FPM).

FPM:

Feet per minute; measurement of air velocity.

Liner:

Fume hood interior sides, back, and top, including baffle.

Lintel:

Portion of fume hood front located above access opening

Louvers:

Slit-like openings in the lintel that allow bypass air to enter the hood when the sash is closed.

NFPA:

National Fire Protection Association.

Negative Pressure:

Pressures lower than one atmosphere.

Positive Pressure:

Pressures higher than one atmosphere.

Restricted Bypass Fume Hood:

Fume hood operating type, designed with limited bypass area; commonly used in conjunction with Variable Air Volume (VAV) exhaust systems and restricted sash opening designs.

Sash:

Sliding glass panel set in the fume hood face that provides access to the hood interior.

Service Fitting/Plumbing:

Water faucets and gas valves mounted on or fastened to the fume hood.

Static Pressure:

Air pressure, or resistance, in fume hood or duct, expressed in inches of water.

U.L. 1805:

Underwriters Laboratories certification that verifies conformance to electrical, mechanical, and airflow standards.

Variable Air Volume (VAV):

Type of fume hood exhaust system that typically maintains constant fume hood face velocity by adjusting blower motor speed or a balance damper in response to changes in sash position.

Velocity:

Speed of air, measured in feet per minute (FPM).

Velocity Pressure:

Force per square inch applied by moving air.

Volume:

Quantity of air, usually measured in cubic feet per minute (CFM).

Work Surface:

Top material; area in fume hood where apparatus rests and where work takes place.