Air barriers in building enclosures are still not widely mandated by building codes in the United States. However, acceptance of incorporating air barriers into new building enclosures is growing within the building design and construction industries, and attempts are being made to add them to existing buildings.

Care must be taken when examining the placement of and requirements for air barriers with specialty buildings such as museums, certain labs, and natatoriums, which can maintain interior relative humidity levels ranging from 35 to 65% when properly controlled and well above 65% when inadequately controlled.

This paper will use examples from projects on which our firm has worked to discuss a method to determine air barrier requirements, including secondary interior air barrier elements. We will discuss considerations for both new and existing construction of specialty buildings to control moisture-laden air. In addition, we will briefly review some of the macro and micro climate considerations for examining moisture-laden air flow with specialty buildings.

Presented at Thermal Performance of Exterior Envelopes of Whole Buildings X – December 2007

Units: SI