Air Barrier Systems Designed to Perform

Transcription

1 Air Barrier Systems Designed to Perform

2 A Broad Range of PROVEN, CONTINUOUS Solutions Sheet-applied membranes Roller-applied membranes COMPREHENSIVE AIR & MOISTURE MANAGEMENT SOLUTIONS Vapor permeable and vapor-retarding air barrier systems Comprehensive systems formulated for compatibility, including: fluid- and sheet-applied membranes, thru-wall flashing, primers, termination mastics, sealants and a patent-pending engineered transition assembly for connections from the air barrier system to the window or curtain wall assembly. The industry s only performance warranty ensuring protection against air and moisture infiltration

3 Taking the Guesswork Out of Air & Moisture Management Air infiltration takes a tremendous toll on a building and its occupants. Energy demands increase as heated or cooled air escapes, moisture and condensation collect in the walls, and the structure and its environment begins to deteriorate. Building envelope components become damaged and structural integrity of the building components may be at risk. Wetting of building materials may lead to mold and mildew. Occupant health and comfort is impacted. Air barriers are only effective, though, when designed as a holistic, continuous system. The Air Barrier Association of America (ABAA) defines an air barrier system as...a collection of building assemblies tied together using air barrier components to provide a continuous plane of air tightness for the whole building. Simply specifying an air barrier membrane is not enough. Codes do not indicate how to achieve an air barrier system and the details are left up to interpretation at the jobsite. Thru-wall flashings Spray-applied membranes Engineered transition assemblies With studies showing that up to 40% of energy consumption in buildings being caused by air leakage and premature building failures conservatively estimated at three to five percent or several billion dollars, the industry has begun a progressive move towards the inclusion of air barriers in building design. Canada has required air barriers since the mid-1980s. In 2001, Massachusetts became the first state to require air barriers by code. The U.S. government and several states now require them on commercial buildings. Hospitals and other institutions requiring controlled environments are demanding them. Code and design acceptance of air barriers is growing daily. While there are dozens of air barrier material suppliers in the marketplace offering products that meet ASTM, ABAA and National Air Barrier Association (NABA) requirements, the numbers of air barrier failures remain high. The key is 1) designing exterior walls and selecting the right type of assembly (i.e. air/vapor barrier or vapor permeable) based on the local climate s impact on vapor drive and 2) ensuring continuity of the system. Being the only manufacturer in the industry with products throughout the building envelope, ensuring compatibility and innovation in system design to provide foolproof continuity has been a major focus at Tremco. Providing an effective, continuous air barrier system need no longer be elusive.

4 Start With the Basics: Climate and Wall Structure Design Designing an effective air barrier system starts with understanding the impact of the local climate on vapor drive. This will allow the proper air barrier membrane (air/vapor barrier or vapor permeable) to be selected and located appropriately within the wall in relation to the insulation. If climates were consistent throughout the year, this would not be a problem. Changing seasons, which may cause dramatic shifts in conditions, complicate the selection. Germany by the Fraunhofer Institute for Building Physics and project information provided by the design professionals, Tremco s Technical Services Team can calculate and illustrate potential wall performance over time based upon how vapor drive and moisture diffusion occur within the design. Data provided, including measured average temperatures, relative humidity, solar load and rain load as a function of time over the period of a year are utilized to view how different types of air barrier designs will perform in different wall locations. Seasonal variations in both temperature and humidity require the use of vapor-permeable air barriers, allowing vapor from inside the building to diffuse to the exterior. Understanding the most prevalent direction of vapor drive for a given climate is essential when designing the exterior wall to handle it, including the selection and location of the air barrier. Tremco offers the industry s only comprehensive vapor-retarding and vapor permeable air barrier systems ExoAir Air Barrier Systems including sealants, mastics and other system accessories formulated to ensure continuity, compatibility and longterm performance. Assistance can be provided on the specification of systems appropriate for the climatic conditions in a given area, the development of specifications to address tie-ins or transitions to window or curtain wall systems and other assemblies and to review details. Using WUFI, the PCbased modeling program developed in Modeling tools, however, assume the air barrier is continuous. Any gaps occurring during installation (or resulting over time) may cause air leakage and are not figured into the program s calculations. It is these small gaps or leaks that cause the real problems leading to disaster down the line.

5 Ensuring Integrity of the System: Continuity and Compatibility Air barriers are designed to stop the movement of air (and the water vapor it contains) under pressure. It must resist live loads including wind pressure (up to the point of a hurricane) from the outside, mechanical loads from heating and cooling equipment and the stack effect from conditioned air. The system must also stand up to significant dynamic pressure changes and air flow when tested. To be effective, the air barrier must be continuous from below grade to the roof line. Providing These breaches may occur as a result of: Material incompatibilities Lack of adhesion with dissimilar materials Improper materials for the application Misapplication or improper sequencing of materials during installation Building design or construction tolerances resulting in large gaps between curtain walls and adjoining walls Penetrations from subsequent trades that have not been sealed and much more. Tremco has formulated and engineered systems designed to ensure compatibility and continuity of the air barrier system. Some manufacturers do not even warranty the use of their own sealants with sheet membranes. With Tremco, that is never a problem. Tremco has highperformance silicone and urethane sealants which have been formulated and tested to ensure compatibility and long-term performance. As much as 90% of all water intrusion problems may occur within the 1% of the total building exterior surface area which contains the terminations and transition detailing. Air Permeance of Common Building Substrates 100,000Xxxxxx Xxxxx Xxxxxx continuity at transitions is critical. If a breach occurs in the building envelope, the amount of water carried through that opening from vapor diffusion may be 30 to 40 times greater than what might be carried through an entire wall over several months. The water produced from condensation from a void is often more than the drainage capacity of the wall and cladding material, potentially leading to rusting and degradation of structural supports and other water-sensitive materials. Costly removal of exterior cladding may eventually be required to find and correct the leak. 10,000 1, x 4 penetration 8 cinder block untreated Cubic feet of air flow/hour Square foot of wall equivalence untreated gypsum board gypsum board w/ air barrier 2,300 1, ,150 22,500 Particularly when temperature gradients between indoors and outdoors are steep, a breach in an air barrier system (as indicated on this chart with the 4 x 4 [102 x 102 mm] penetration) will create a strong vapor drive. This forces humidity through the opening and into the wall, where large amounts of water condense when humidity reaches the dewpoint. In a perfectly sealed air barrier system, this small penetration allows the same amount of air/vapor diffusion as 6150 square feet (571 m 2 ) of untreated, exterior-grade gypsum board.

6 A COMPLETE, PROVEN Solution for Even the Most Challenging Jobs When construction tolerances generate larger gaps between curtain walls and adjoining walls or building designs incorporate geometries that result in difficult intersections, providing an adequate, durable, consistent connection with a sealant may be impossible. To respond to this challenge, Tremco has invested extensive time and resources in the development of a patent-pending engineered transition assembly that can span and seal across irregular window barrier assembly utilizing stringent ASTM E 2357 criteria, Tremco is setting the bar even higher by testing for air leakage throughout the building envelope by incorporating Proglaze ETA as part of the tested air barrier-window/ curtain wall continuous envelope assembly. Proglaze ETA was developed and tested to ensure long-term air and moisture protection when used in conjunction with ExoAir 110 and 110LT (Low Temperature) Self-Adhered Air & Vapor Barrier Membranes, ExoAir fluid-applied membranes and ExoAir TWF Self-Adhered Thru-Wall Flash- geometries while absorbing dynamic movement and wind-loading stresses without pulling apart. ing Membrane at transitions into door and window openings or curtain wall systems. The patent-pending Proglaze ETA Engineered Transition Assembly provides the first PROVEN solution to simplify the installation of transitions from window or curtain wall systems to wall assemblies. Provided from a single source, this revolutionary solution can be easily specified and ensures accountability. In an air barrier system, any component used to make a connection must become a structural element of the wall assembly, capable of moving and deflecting wind-load stresses without pulling apart. Extensive thirdparty testing has proven how well this system works withstanding water penetration, thermal changes, load deflection and air infiltration. In fact, it works so well that Tremco is offering the industry s first performance warranty when these products are used together. No more interpretation on the job. No more risk. Simply a PROVEN solution engineered to ensure longterm performance. Performance You Can Depend On Guaranteed To ensure performance under realworld conditions and long-term sustainability, ExoAir Air Barrier Systems have been tested not only on their performance as an exceptional air

7 A Single Source for a Superior Solution Committed to Long-Term Performance Design Integration and Collaboration Advances in building envelope technologies coupled with a whole building design approach that optimizes the interactions among building systems and components will enable tomorrow s buildings to use significantly less energy and reduce their environmental impact over the life of the building. Continuity throughout the building envelope is key. With the industry s broadest offering of building envelope components, Tremco is in the unique position of being able to provide comprehensive, compatible solutions that will ensure connectivity at critical tie-ins at window to wall, wall to roof, below-grade to deck and more. On-Site Assistance and Best Practice Education Tremco has knowledgeable, technical sales representatives in every major market across the country who can help with specificarion development, guidance on sequence of installation and appropriate tie-ins to ensure the integrity of the system is not compromised, on-site assistance and problem-solving. Utilizing proven best practices for integrated design and installation, they can help simplify specification and installation, eliminate trial and error, reduce callbacks and the liability associated with poor design or installation. Documented Performance Under Real World Conditions Material performance and even assembly performance are only the price of entry when it comes to the selection of an air barrier system. Tremco is committed to ongoing testing and is continually working towards documenting performance as it relates to uncontrolled air and vapor infiltration. Beyond concerns over gaps and incompatibilities which may occur during construction, driving rain, dynamic wind loads, thermal movement and seismic conditions can direct a tremendous toll on building envelope connections, leading to air and moisture infiltration and a host of disastrous consequences. Tremco s commitment to long-term performance means a commitment to testing that will push the envelope.

8 A Single Source for a Superior Solution 3735 Green Road, Beachwood, OH Phone: Jacobson Avenue, Ashland, OH Phone: Wicksteed Avenue, Toronto, ON M4H 1G7 Phone: ABS