Phased rehabilitation and upgrading to “low flow” fume hoods in the Chandler Hall science building on the Morningside campus is yet another contribution to Columbia’s energy-saving efforts.

A fume hood is a piece of lab safety equipment in a system comprising a hood, ductwork and exhaust fan. Its purpose is to capture the toxic, corrosive, flammable or simply foul-smelling air from a process such as mixing chemicals. The contaminant is then carried through the ductwork by an exhaust fan and discharged in a manner that ensures dilution to safe levels.

The system needs a constant source of new air -- known as makeup air -- to replace the air being drawn out of the hood. In winter, the makeup air must be heated, and in summer, cooled, to maintain a comfortable work environment. The low-flow fume hood requires less air to operate, which translates into energy savings because less air needs to be heated or cooled. More energy savings result from smaller fans in the new hoods.

The 54 low-flow fume hoods on the seventh, eighth and ninth floors of Chandler save the equivalent of five gallons of home heating oil per hour when the outside temperature is 15 F.

Over the course of a year, their environmental benefit is a 4.6 million-pound reduction in carbon dioxide emissions. That’s equivalent to what could be saved in auto emissions by five million miles of not driving.