Mitigating the Impacts of Uncontrolled Air Flow on Indoor Environmental Quality and Energy Demand in Non-Residential Buildings

Secondary Author(s)

Walburger, Adam; Zhang, Jensen; Bomberg, Mark; Salonvaara, Mikael; Cummings, James; Withers Jr., Charles; Gu, Lixing; Brennan, Terry; Clarkin, Mike

Report Number





HVAC; Buildings; Air Flow; Air Quality


This project builds on previous field research in Florida that has demonstrated the significant impact that uncontrolled air flows (UAFs) have on indoor environmental quality (IEQ) and energy use in small commercial buildings, a large but poorly understood segment of the nation's building stock. The goal of this project was to extend that research to a national scale by assessing the importance of UAFs in a sample of 25 commercial buildings in New York State. The differences in climate and construction techniques between New York and Florida areexpected to bound the range conditions typically found on a national basis. The project also completed a series of carefully-controlled full-scale laboratory experiments and computer simulations to further understand the nature and impact of UAFs on air quality, occupantcomfort, and energy use. The research results from this project provide the basis for developing improved construction and diagnostic techniques that will ultimately result in higher quality and more energy efficient buildings that result in lower peak demand on the nation's electric system. Research at the Florida Solar Energy Center (FSEC) has shown that commercial buildings are three times 'leakier' than residential buildings and that unintended interactions between the forced air systems, the building envelope, and the interior zones have substantial impacts on IEQ. Florida's research found that 69 of the 70 non-residential buildings tested exhibited substantial 'uncontrolled air flow' that resulted in building problems (Cummings et al 1996). Repair of 20 of these buildings resulted in cooling energy savings and demand reductions of 15%, and in many cases substantial improvement of indoor temperature and relative humidity. This project extended the Florida work to a national basis by completing a similar field survey ofsmall commercial buildings in NY State. New York buildings are expected to exhibit some differences in construction details that are typical of buildings in the Northern US. Furthermore, it is expected that there will be substantial differences in the magnitude and form that uncontrolled airflow takes in New York compared to Florida because of climate. It is important, therefore, to characterize the building envelope and HVAC system elements of New York construction that contribute to uncontrolled air flow, and perform field testing and monitoring to reveal the climate-specific response. The research also used newly-constructed laboratory facilities at FSEC and Syracuse University (SU) to carefully quantify the physical mechanisms driving UAFs as well as their impacts on energy use, IEQ and building durability. FSEC's whole-building test lab focuses on interactionsbetween the HVAC system, ductwork, and the building envelope. SU's Coupled Indoor/Outdoor Environmental Simulator (C-I/O-ES) test facility focuses on the dynamic impacts of UAFs in built-up wall assemblies. The experimental tests in both facilities were designed and evaluatedconsidering the building characteristics and measured results observed in the New York and Florida field surveys. Both whole building and wall assembly computer simulations were developed and verified using the experimental results in order to extend the findings over a widerarray of climates and configurations.

Date Published



Buildings - Air Flow; Buildings - Air Quality; Buildings - HVAC

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