Share the Air: Cascading Air Strategies Using Neutral Temperature DOAS

Craig Spangler, Ballinger
Jonathan Friedan, Ballinger

For laboratory buildings, there is a simple rule to maximize energy efficiency: Reduce ventilation requirements as much as possible without compromising safety. To meet this objective designers have turned to technologies such as high performing fume hoods, chilled beams, and demand-based control of laboratory ventilation. A complimentary strategy is via the transfer and re-use of air from non-lab program, a term the authors have coined Air-Share. This presentation will cover the implementation of this concept and will demonstrate how the use of dedicated outdoor air systems (DOAS) with neutral temperature supply air has changed fundamental parameters of laboratory building design. Impacts to control zones, compartmentalization, ductwork, balancing, and airflow capacity will be discussed. The presenters are an architect and mechanical engineer that have collaborate in an integrated design practice. Three case studies will track the development of broad ideas about how to maximize energy savings using these techniques.

The first is the LEED Platinum Undergraduate Labs for Johns Hopkins University, which used a plenum supply and passive baffle system to balance out pressure between load and ventilation driven lab environments. The second case study is the Interdisciplinary Life Science Building for the University of Maryland which is currently under construction. This building permits air to flow from dry spaces through a central commons and then into the labs for use as passive balance makeup air. Issues of fire separation and control areas are addressed as part of this solution. The third case study is for a project still on the drawing board that will use a double fašade to supply neutral temperature air for flow through circulation in dry spaces and then into labs for make-up. Each of these projects builds on the successes and experiences of the previous and in the context of integrated design can lead to substantial savings in construction cost, energy use, and maintenance. The presenters are very experienced in addressing these issues, and the case studies presented are from the body of their own direct work. The techniques presented derive from having constructed multiple neutral temperature supply air buildings, and allow them to propose next generation systems and approaches resulting from an integrated practice milieu.

Learning Objectives

  • Understand how neutral supply temperature systems separate ventilation from heating and cooling, and how this creates opportunities to re-imagine traditional ventilation strategies.
  • Maximize energy savings by sweeping air from dry spaces into wet labs. Understand how compartmentalization impacts air flows and pressures.
  • Understand the critical components of these systems and how they work together to reduce first costs, energy use, and maintenance.
  • Bear testimony to the results of open collaboration between architects and engineers in the spirit of integrated design. Appreciate how the resulting projects are stronger designs due to the willingness of each to accommodate the input of the other as an equal partner. Easy to say, hard to do.


With over 35 years of professional experience, Craig Spangler has led a broad spectrum of significant commissions for the academic community. His commitment to design excellence for innovative, high performance buildings has resulted in numerous national and local design awards. He has been published widely and is a frequent speaker at academic facility forums across the country. Craig earned a Bachelor of Architecture from the University of Maryland and a Master of Architecture from Princeton University.


Jonathan is a leader in developing high performance systems and retrofit strategies for major academic science and research facilities. His significant resume of built facilities exhibit a sensitivity to programmatic function, innovative use of appropriate technology, and a practical sense of reliable building operations. He earned a Bachelor of Arts from Columbia College and a Master of Science in Mechanical Engineering from Columbia University.


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