Neil W. Garry, RRC, REWC, PE | Bell & Spina Architects | Strong Memorial Hospital, University of Rochester | Rochester, New York
Bell & Spina Architects was retained by the University of Rochester Medical Center to review the construction of the windows on Floors 2, 3, and 4 of the center’s Emergency Department. The original building was constructed up to Floor 2 in 1999, and Floors 3 and 4 were added in 2003. The facility had reportedly experienced seasonal condensation at northerly window surfaces since the upper floors were added to the building. To accommodate the Burn Unit, located on Floor 3, relative humidity (RH) levels had been maintained at approximately 40%. Over the course of the winter of 2014-15, heavy condensation was found to have developed on the northerly windows to such an extent that migration of the condensed water caused complications to the electrical system.
Our study consisted of investigative removals, visual reviews, and the evaluation of records from both the 1999 construction and 2003 addition. Current RH and temperature data were collected with a digital hygrometer. Infrared images were taken using a Flir camera. A THERM mathematical dew point analysis of the typical wall profile under average winter weather conditions was also completed. Our objective was to identify the extent to which the condensation risk could be managed and/or reduced.
We concluded that the window jambs at Floors 2, 3, and 4 are thermally coupled with the air in the wall cavity. As presently constructed, the interior surface temperature of the window jambs at all three floors will remain below the dew point under the standard regional ASHRAE exterior design temperature of 1°F (-17°C). This places these surfaces at risk of condensation under common, low-temperature winter operating conditions.
We recommended that the window jambs at the affected floors on the north elevation be thermally decoupled from the air in the wall cavity. The first scenario proposed included removal and replacement of the brick in proximity to the jambs at all three floors from the building exterior to enable sufficient access to insulate the jambs without evacuating the patient rooms. The second scenario was to replace the fenestration entirely at all three floors with a thermally broken system. Both scenarios included an opinion of probable construction costs. The hospital has not determined a course of action.