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Fume Hoods -

Fume hoods are notorious for consuming expensive resources, particularly electricity and conditioned air that is vented to the environment along with volatile chemicals and other toxins.

Fume hoods are notorious for consuming expensive resources, particularly electricity and conditioned air that is vented to the environment along with volatile chemicals and other toxins.

A decade ago, low-flow hoods revolutionized the industry by reducing air throughput and related energy costs by 40 percent. According to Jon Zboralski, director of air flow products at Thermo Fisher Scientific (Two Rivers, WI), the industry still considers low-flow hoods “new” despite their ten years on the market and hard evidence they can save facilities as much as $2,400 per year per hood.

More recently, ductless hoods changed the equation yet again in favor of greater energy efficiency and cost savings.

Ductless fume hoods use activated carbon filters to remove toxins from the airstream. Unlike traditional hoods, which vent tens of thousands of cubic feet of heated or air-conditioned workspace per day, ductless fume hoods return conditioned air to the lab. “This translates to a significant drop in energy use,” observes Kevin McGough, president of AirClean Systems (Raleigh, NC).

Equipment longevity also plays into the idea of a “green” laboratory. Although fume hoods do not “wear out” like other laboratory fixtures, they have a finite usable life. Customers, according to Mr. McGough, pay close attention to quality, materials of construction, and anticipated product lifecycle. In response, fume hood manufacturers have embraced the use of polypropylene, a specialty of AirClean. Compared with metal, polypropylene offers advantages of corrosion resistance and seamless/ gapless construction.

AirClean customers have been requesting mobile fume hoods to accommodate expanding or changing workflows and to avoid costly construction costs associated with vented hoods. “Ductless solutions are key here,” Mr. McGough says, “as they need not be connected to the facility’s HVAC system and may be moved from one work area to another in minutes. The only requirements are an electrical outlet and at least six inches of clearance from the ceiling.”

Traditionalists may recoil from the idea that chemical-laden air can be cleaned and returned to the work area. Manufacturers are quite aware of this and have bent over backward to demonstrate that ductless technologies are safe and work as advertised.

A ductless fume hood requires no ductwork, arrives fully assembled, and may be installed in locations where, barring a significant and expensive renovation process, a traditional fume hood could not.

At the time of their introduction, ductless hoods were limited by their filtration systems, which tended to be application-specific. “If you used formaldehyde, you needed a filter specifically designed for removing formaldehyde,” says Mr. McGough.

That is changing rapidly with the 2009 debut, from Erlab (Rowley, MA), of Neutradine molecular filtration, a type of super-activated carbon that is nearly a universal chemical absorber. Neutradine incorporates binding sites for various chemical families, and neutralizes acids as well. Independent tests have demonstrated this filtration medium removes 98 percent of all chemical fumes used by 99.9 percent of laboratories. Erlab has partnered with Thermo, Airmaster, and ALC Collegedale to supply Neutradine media for ductless hoods.

Independence Ductless

  • Provides a new onboard chemical database with over 1,000 approved chemicals
  • Built-in gas analyzer can give absolute exhaust and Interfilter values in ppm
  • Allows for one gas filter that fits most gas phase applications
  • Features AirClean Operating System written exclusively for fume hoods
  • Combines ‘true zero’ gas measurement with multiple gas detection methods

AirClean Systems

Purair 20 Ductless

  • A face velocity at 100 fpm ensures containment of fumes and an alarm will alert the operator when the airflow falls to an unacceptable level
  • All mechanisms in the head section are on the clean side of the filter, preventing contamination
  • 49” wide by 27.5” deep by 47.5” high. Other sizes are available up to 96” wide.

Air Science USA

SE Aire-Stream

  • UL 1805 certified and offered in 48”, 60”, 72” and 96” widths in either constant air volume or restricted bypass models
  • Features molded one piece seamless white surface and all corners coved for easy cleaning and light reflectivity
  • Maximizes user protection and energy savings


Protector® XStream®

  • Performs well at low air volumes
  • Operating the unit at OSHA-approved 60 fpm provides significant energy savings compared to operating a traditional hood at 80 or 100 fpm
  • Has patented features that work together to significantly reduce the concentrations of contaminants in areas behind the sash opening and near the user’s breathing zone