Track 1: Decline vs. Revival: Tempering the Impulse to Tear Down and Start Over

APT Student Scholar Abstract

High-performance retrofits of Mid-Century Curtain Wall: A case study analysis of opportunities to enhance thermal performance using low-impact, reversible solutions.

Tuesday, September 25
8:30 AM - 10:00 AM
Location: BNCC- 101AH
Faculty Advisor: Laura Blokker, Program Assistant Director – Tulane University

American International style glass buildings face tremendous obstacles to their perpetuity, especially considering their poor thermal performance. The non-thermally broken frames and single-pane glass conduct higher rates of heat intensity across the envelope’s section, which leads to inadequate thermal comfort, higher building operational costs, and accelerates decay through excessive expansion, contraction, and condensation. Holistically, the subsequent deterioration precipitates safety issues, higher maintenance costs, and higher building energy usage – all of which places pressure on building owners to remove and replace the old curtain wall with new systems.

This study’s objective is to identify modifications that improve the curtain wall’s insulating performance for the purpose of preserving the existing glass envelope, improving envelope thermal performance, and encouraging sustainability through the reduced environmental impacts achieved by the building’s continued use. This research discusses opportunities for envelope enhancement through a comparative investigation of three American, mid-century case study buildings:
 Lever House, located in IECC Zone 4, New York, New York;
 Ford Motor Company, located in IECC Zone 5, Dearborn, MI;
 New Orleans City Hall, located in IECC Zone 2, New Orleans, Louisiana

This study’s methods employ energy simulation analysis software THERM 7.4.14 and WINDOW 7.4.14, developed by Lawrence Berkeley National Laboratory, to model two-dimensional heat-transfer effects in cross sections of the curtain wall framing components. Material assemblies are custom created in the software per original building drawings. Each case study analysis is localized to the curtain wall’s typical “module”, which is the typical arrangement of mullions and glass that repeats to compose the whole facade. The module energy analysis is simulated for the existing baseline and the proposed retrofits, which are evaluated per the following incidences:
 Total System U-factor
 Solar Heat Gain Coefficient
 Visual Light Transmittance
 Condensation Resistance

The study results show that a combination of noninvasive modifications both improves upon the baseline and meets the modern standards of the International Energy Conservation Code. In order to optimize performance, the enhancement design is specific to the regional climate and follows either a passive solar heating or solar control strategy. The retrofits investigated include glazing treatments, new supplementary interior glazing panels, and conceptual detail best practices. The glazing treatments considered include surface applied films, chemical tints, and low-emittance coatings. This new assembly is reversible, provides an “insulating” air space between the existing and new frames, provides a glazing surface that can be treated with a high-performance coating, and can be hidden behind the existing glass curtain wall so as not to detract from the original exterior appearance. Ultimately, the retrofit scenarios seek to extend the envelope’s usable life, render a higher-performing envelope, and offer a sustainable and economical solution that considers preservation and building functionality.

Learning Objectives:

Brittany C. Foley, NCARB, AIA, LEED AP BD+C

Architect / Graduate Student
Tulane University

Brittany Foley is a licensed architect with expertise in historic building restoration, adaptive reuse, and architectural material conservation. She has extensive experience with projects utilizing the Federal Historic Preservation Tax Incentives Program, which fuels her passion for urban revitalization and re-servicing historic buildings to support and foster vibrant, equitable, and sustainable communities. Brittany’s specialty interests include the conservation of modern architecture and the applied science of retrofitting historic buildings to enhance envelope performance.

Brittany recently graduated from Tulane University with a Master in Preservation Studies, where she culminated her education with the thesis: High-performance envelope rehabilitation methodologies for Mid-Century glass curtain walls.
She has returned to private practice as an associate and senior project manager with Williams Blackstock Architects.

Brittany is an active member of the American Institute of Architects, the U.S. Green Building Council, the Association of Preservation Technology International, and she serves as the chair of the City of Homewood’s Historic Preservation Commission.


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Sue Ann Pemberton, FAIA

Assistant Professor in Practice
University of Texas at San Antonio

Sue Ann Pemberton, FAIA, has straddled between private practice and academia for more than thirty years. She holds a Master of Architecture Degree and Bachelor of Environmental Design from Texas A&M University. Her focus of practice, study, and teaching includes design, materials research and technology, inner city development, and historic preservation of buildings, neighborhoods and communities. Sue Ann leads the Historic American Building Survey program in the College of Architecture, Construction and Planning at the University of Texas at San Antonio.


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High-performance retrofits of Mid-Century Curtain Wall: A case study analysis of opportunities to enhance thermal performance using low-impact, reversible solutions.

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