Fume Hood Automatic Sash Positioners—Results of a Three-Year Pilot Program and Retrofit

Chris Case, Affiliated Engineers, Inc.

This presentation describes the results from a three-year pilot program where six VAV fume hoods were equipped with automatic sash closing systems. Airflow and safety data for these six fume hoods, and a control group of six VAV fume hoods not equipped with automatic sash closers, was collected for three years.

On the strength of the data, an additional 50 fume hoods were retrofitted with the automatic sash closing systems. Data for the actual installation costs, construction issues, and measured energy savings was also collected.

The presentation covers:

  1. Measured airflow reductions of 50 percent over conventional VAV fume hoods.
  2. The measured frequency of use of fume hoods by chemists in their natural environment.
  3. The measured compliance of the occupants in closing their conventional hoods.
  4. Energy savings and retrofit costs, a three-year payback in California's climate.
  5. How environmental health and safety perspective changed from apprehension that the automatic sash would cause safety issues in the hood to appreciation of the safety provided by the closed sash.
  6. The reductions in airflow allowed reduction in the supply air system airflow and static pressure set points and allowed half of the exhaust fans to be turned off permanently.
  7. Applicability of automatic sash closing systems to other laboratories, defining fume hood density and its relationship to minimum air change rates.
  8. Application to a new laboratory, and how to save energy and capital costs simultaneously.
  9. Implications in fume hood sash design; when the sash is closed most of the time, which sashes are the most cost effective?

Biography:

Chris Case is a project manager with Affiliated Engineers, Inc. and is also the process group leader in the San Francisco Bay Area office. Mr. Case graduated from Northeastern University in Boston, Massachusetts with a Bachelor of Science in mechanical engineering. In his 26 years of mechanical engineering, Mr. Case has established expertise in cleanroom, laboratory, and bio-containment facility design.

Mr. Case has engineered and managed numerous projects, including: Revance, a 90,000-square-foot common good manufacturing practices fermentation and purification production facility utilizing a biosafety level 3 rated organism; the University of Wisconsin Engineering Centers Nanotechnology cleanroom design; and the 140,000-square-foot University of California, Berkeley's, Hearst Memorial Mining Building. In addition to starting his career as an energy auditor, Mr. Case has recently completed sustainability studies and retrofits for Amgen, Genentech, Stanford University, and CB Richard Ellis.