Rex Cyphers, Annette Cyphers and Jodi Knorowski
Rex Cyphers, Principal, WDP & Associates Consulting Engineers, Inc., 335 Greenbrier Drive, Suite 205, Charlottesville, VA 22901, USA, rcyphers@wdpa.com.
Annette Cyphers, Director of Facilities Planning and Construction, University of Virginia, 575 Alderman Road, Charlottesville, VA 22904, USA, amo2b@virginia.edu.
Jodi Knorowski, Project Engineer, WDP & Associates Consulting Engineers, Inc., 335 Greenbrier Drive, Suite 205, Charlottesville, VA 22901, USA, jknorowski@wdpa.com.
ABSTRACT
Energy conservation has become one of the primary goals of architecture and engineering design today, and with this growing awareness for energy efficiency, the need for properly evaluating thethermal and moisture properties of existing and historically significant buildings must be addressed. Without proper evaluation, changes to the thermal and moisture properties of the exterior walls can have serious negative impacts, such as degradation of the existing masonry or interior finishes along with interior air quality and other moisture related issues. To complement current design tools, effective field studies to evaluate existing buildings will improve the quality of data available and analytical results. While many historic mass masonry buildings may not meet the prescriptive minimum insulation requirements of today’s energy codes if the total R-value or U-factor are calculated, they do have the inherent ability to absorb, store, and later release significant amounts of heat. This thermal mass provides an intrinsic energy-saving advantage as the materials within the walls absorb energy slowly and hold it for longer periods, reducing heat transfer through the mass wall as compared to framed wall assemblies. A field study and subsequent analysis was performed at two historical mass masonry buildings at the University of Virginia and West Virginia University. Various data logging instrumentation was installed to measure temperature, relative humidity, heat flux, and radiation at critical points within the wall section to determine how heat and moisture were transferred through the wall assemblies. The insitu thermal resistance of the wall assemblies was evaluated during rain events and periods of high exterior vapor pressure and compared to the overall thermal resistance calculated over the duration of the testing period.
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