Energy efficiency has taken on increasing importance as fuel costs rise, our economy struggles, global warming debates become more frequent and sustainability becomes more of a mainstream imperative.
Performance standards for buildings are being developed and implemented to include required criteria that set higher standards for allowed air leakage, thermal performance and overall energy use and system efficiencies. The most stringent standard today is the Passive House standard developed in Germany in the late 1980s, with an air change rate standard of 0.6 ACH 50 Pascals. With implementation in more than 30,000 buildings worldwide, it demonstrates unsurpassed performance when it comes to indoor air quality, comfort, minimized energy use and related costs for heating and cooling. In order to reach these stringent standards, an airtight building envelope and the elimination of thermal bridges is mandatory.
Throughout the seasons, energy moves through walls, be it cool air lost to the outside in the summer or warm air in the winter. Thermal bridging and air infiltration are two of the largest contributors to energy loss generating up to 50% of the heat loss in a traditional building. An airtight and thermal bridge-free envelope ensures heat, and consequently energy generated in a building, is not wasted.
The multi-family housing environment must also take into consideration acoustical and firestopping requirements, in addition to air sealing requirements, treating each unit as a self-contained environment. An integrated design of a wall system to meet all these requirements incorporated Tremco's ExoAir® 230 Fluid-Applied Vapor-Permeable Air Barrier Membrane, flashing membranes and an innovative, multi-functional compressed tape as an all-in-one sealing system. When tested at Tremco's Sustainable Building Solutions Test Facility, this holistic approach to wall system design surpassed even Passive House standards, leaving sufficient room for anything that might be encountered during actual construction conditions.
All assemblies PASSED tests with air exchange rates of less than 0.43/hour @ 50 Pa. To meet stringent passive house standards, a rate of 0.6 or less is required.
The following tests were conducted on the multi-family housing wall. Click on the links for full test reports.
Internal Wall Assembly
External Wall Assembly
ASTM E90 Standard Method for Laboratory Measurement of Airborne Sound Transmission testing was also done to determine the sound rating with and without Tremco's ExoAir® Trio open cell polyurethane foam compressed tape as the sealing system used in the ½" slots of the acoustical assembly. Sound transmission loss, the difference between the sound level in the source room and the receiving room, is measured at specific sound frequencies and used to arrive at the Sound Transmission Class (STC) rating. The higher the STC rating calculated, the quieter it is in the receiving room. The rating without the ½" slot sealed was 19 STC. The acoustical assembly with ExoAir Trio tested at 54 STC. Typical interior walls in homes have an STC of about 33.