A New Change to the Laboratory Energy Paradigm: Revisions to the ANSI Z9.5 Fume Hood Minimum Ventilation Rate
Gordon Sharp, Aircuity, Inc.
Many laboratory facilities have transitioned to VAV controls to save energy, however, do these systems go far enough or can further reductions be made to achieve even greater energy reductions without compromising safety?
To achieve the current levels of energy reduction in laboratories, new innovations and design approaches have been applied to drive laboratory airflows down to as low as safely possible. Some of these approaches consist of using high performance fume hoods to drop face velocities, demand-based control of air change rates to reduce room airflows to as low as 2 ACH, and chilled beams to decouple laboratory airflows from the cooling loads. However, one of the significant barriers to extracting further energy savings in laboratories from these and other airflow reduction approaches has been the widely adopted fume hood minimum flow guidelines set forth by both NFPA 45 and the ANSI Z9.5 Laboratory Ventilation Standard. For many laboratories with fume hoods these minimum flow guidelines can increase energy use significantly when hoods are not being actively used and the sashes are closed.
Recently evidence has been surfacing that these minimum flow guidelines are overly conservative at least for most laboratories. As a result, an approved change to the new 2009 NFPA 45 standard will drop the fume hood minimum flow recommendation and will instead refer this to ANSI Z9.5. For its part the ANSI Z9.5 standard is also being revised (due out for public review before the end of this year) to recommend not a single value but a range of minimum fume hood flows that is based on the internal volume of the hood. For many hoods this represents a range that has a maximum of about the current minimum flow rate and a minimum down to 40 percent of that. At the minimum, this change if applied conservatively to the existing base of VAV fume hoods in the U.S. could represent an energy reduction in excess of $150 million annually or about half the impact of all the solar PV generation installed in the U.S. by the end of last year.
This and the preceding presentation, Establishing Minimum Flow Rates for Laboratory Hoods, will discuss the proposed changes to the ANSI Z9.5 relating to the fume hood minimum. It will also cover the design and energy savings impacts of this change as well as important design and application tips for retrofitting existing laboratories and design of new laboratories to maximize potential savings without compromising the safe operation of the laboratory. Finally, a review of current research and pertinent industry data will be presented to help provide consultants, safety professionals, and owners with a basis for using the lowest appropriate fume hood minimum within the recommended range.
Biography:
Gordon Sharp has more than 25 years of wide-ranging entrepreneurial experience and more than 25 U.S. patents in the fields of energy efficiency and laboratory controls. From 1979 to 1985, he was vice president and co-founder of IMEC Corporation, a motor controls technology company from which he created a spin-off company called the Phoenix Controls Corporation. As president, CEO, and founder of Phoenix Controls, Mr. Sharp led the development of a world leader in laboratory airflow controls that, under Mr. Sharp's leadership, was honored for three consecutive years by INC magazine as one of the 500 fastest growing private companies in America. In early 1998, Honeywell, Inc. acquired Phoenix Controls. Thereafter, Mr. Sharp led the development of the Honeywell business unit now known as Aircuity, which became an independent, venture capital backed company in January of 2000. Today Aircuity is the leading manufacturer of building energy and environment information systems for airside energy efficiency for both laboratory and nonlaboratory facilities. Mr. Sharp is the chairman and founder of Aircuity and a graduate of the Massachusetts Institute of Technology with a Bachelor's and a Master's degree in electrical engineering. He is a member of the ANSI Z9.5 Laboratory Ventilation Standard committee and a member of the board of directors of I2SL.