May Chapter Meeting – Underfloor Air Distribution

Event Details

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Underfloor Air Distribution Systems (UFAD) have rapidly penetrated the office building arena across the United States because they provide a number of advantages (and few disadvantages) over conventional office building HVAC systems. This session will present new design approaches and new solutions that refine and improve the performance and flexibility of UFAD systems. Some of the issues to be dealt with include maintenance of uniform supply temperatures in the underfloor plenum, evaluation and exploitation of thermal stratification in the occupied spaces, avoidance of leakage issues in the floor plenum, control of space humidity for humid climates, and maintenance of comfort conditions in all occupied spaces.

Learning goals for the presentation:

After the presentation, the attendee should be able to

  1. Identify projects that might be appropriate for underfloor air distribution and which might not be appropriate.
  2. Employ new approaches to underfloor air distribution system design that enhance flexibility and efficiency of the system.
  3. Recognize construction issues for this technology and learn how to avoid them.
  4. Identify appropriate design tools to use to insure that designed systems will meet performance goals.


Consulting Engineer

Mr. Nall is a professional engineer, an ASHRAE and an AIA Fellow, a LEED Fellow, an ASHRAE certified Building Energy Modeling Professional, a certified High Performance Building Design Professional and a Certified Passive House Consultant. He is an ASHRAE Distinguished Lecturer and is the chair of ASHRAE Standards Committee (SPC) 227, the Passive Building Standard.  He was one of the authors of the Engineer’s Notebook column in ASHRAE Journal.  He is an author of ten of ASHRAE’s fourteen Advanced Energy Design Guides (AEDG) and is the AIA Representative on the AEDG Steering Committee. He is a current member of and was the vice chair of the ACEC NYC Chapter Energy Code Committee and is  a member of the NYC Buildings Sustainability Board. He was Vice Chair of the ASHRAE Standard 189 committee (USGBC nominee), was recipient of the ASHRAE Journal Paper Award in 2013, the ASHRAE Distinguished Service Award and ASHRAE New York Chapter Distinguished Service Award.  He was a Director of the USGBC NY Chapter, a member of the AIA Committee on the Environment Advisory Group, and Vice Chairman of the USGBC Energy and Atmosphere Technical Advisory Group. He was one of Engineering News Record’s “Newsmakers of 2007.” He received the “Outstanding Practitioner Award” from the US Chapter of the International Building Performance Simulation Association (IBPSA) in 2004. He has been a faculty member at the Schools of Architecture at the University of Pennsylvania, Princeton University, Cornell University and Columbia University. He has been involved in energy efficiency and sustainability in buildings for over 40 years and is the author of numerous papers in professional and technical journals. He has also presented at numerous USGBC, AIA and ASHRAE national conferences and conventions, and at international events in Spain, Italy, Brazil, Argentina, UAE, India, and Indonesia.