For professionals involved in commercial construction and building envelope systems, selecting and applying the correct air barrier is a critical step in ensuring energy efficiency, structural integrity, and compliance with fire and safety regulations. Tremco Sealants' ExoAir 230 is a fluid-applied, synthetic air and vapor permeable membrane designed for use in high-performance building envelopes. This guide provides an in-depth look at the product, its key features, and its application methods, based on information from the manufacturer’s documentation and product specifications.
Understanding ExoAir 230 and Its Applications
ExoAir 230 is a fluid-applied air barrier engineered to mitigate air infiltration and water penetration while remaining permeable to water vapor. This dual functionality makes it suitable for a wide range of commercial applications where both air sealing and vapor transmission are important considerations. The product is particularly well-suited for projects that require NFPA 285 testing, a critical standard for assessing the fire performance of non-load-bearing exterior walls in multi-story buildings.
One of the key advantages of ExoAir 230 is its application flexibility. The material can be applied using a roller, sprayer, or trowel, allowing for adaptability across different project types and site conditions. It is also designed to maintain performance in a variety of environmental conditions, with service temperatures up to 240°F (115°C) and a 12-month UV resistance rating. This makes it a viable option for both interior and exterior applications where temporary exposure to sunlight may occur during installation or prior to final cladding.
The product’s vapor permeability is an essential feature in modern building design. Unlike traditional vapor-impermeable air barriers, ExoAir 230 allows for the controlled passage of water vapor, reducing the risk of condensation buildup and potential moisture-related issues such as mold or rot. This is particularly beneficial in climates with high humidity or where building materials are prone to moisture retention.
Key Considerations for Selecting an Air Barrier
According to the documentation, there are seven critical factors that should be considered when choosing the right air barrier for a given project:
- Climate Conditions: The local climate, including temperature extremes, humidity levels, and precipitation, should dictate the type and performance level of the air barrier selected.
- Fire Performance: For projects subject to fire safety codes, especially those involving multi-story structures or combustible cladding, an air barrier must meet standards such as NFPA 285.
- Membrane Thickness: The thickness of the applied membrane can influence its durability, resistance to tearing, and long-term performance.
- Facade Anchors: In some applications, especially those involving curtain walls or cladding systems, additional mechanical anchoring may be required to ensure the air barrier remains intact.
- Compatibility: The air barrier must be compatible with adjacent materials, including insulation, sheathing, and coatings, to avoid delamination, adhesion failure, or chemical incompatibility.
- Application Method: The ease and practicality of applying the material using available tools and labor resources should be evaluated.
- Project-Specific Requirements: Custom requirements such as aesthetic considerations, acoustic performance, or integration with other building systems may further refine the selection process.
These factors highlight the importance of a tailored approach to air barrier selection. ExoAir 230 is presented as a solution that aligns with these considerations, particularly for commercial applications where performance, compliance, and adaptability are paramount.
Application Methods and Tools
ExoAir 230 offers a high degree of versatility in its application, allowing for use with three primary methods: roller, sprayer, and trowel. Each method has its own advantages and is suited to different project conditions and material requirements.
Roller Application: This method is ideal for flat or gently sloped surfaces where a uniform coat can be easily applied. It allows for precise control over the thickness of the membrane and is suitable for large, open areas.
Sprayer Application: Spraying allows for faster coverage and is particularly effective for complex geometries or areas that are difficult to access with a roller. It ensures consistent thickness and minimizes labor time, though it may require more preparation to protect surrounding areas from overspray.
Trowel Application: Troweling is suitable for achieving a thicker, more robust membrane and is often used in areas where additional mechanical strength is required, such as at joints, edges, or transitions between materials.
Regardless of the method used, the documentation emphasizes the importance of thorough surface preparation prior to application. The substrate should be clean, dry, and free of contaminants that could interfere with adhesion. It is also recommended to apply the material in a uniform thickness, ensuring full coverage and continuity across the surface.
Performance and Environmental Tolerance
ExoAir 230 is engineered to perform under a range of environmental conditions, making it a suitable option for both interior and exterior applications. One of the notable features is its 12-month UV resistance, which allows the material to remain exposed to sunlight without degradation for up to a year. This is particularly beneficial in projects where installation may be delayed or where temporary exposure occurs before final cladding is applied.
The product also maintains performance across a broad temperature range, with service temperatures up to 240°F (115°C). This makes it suitable for use in heated structures or in areas where elevated temperatures may be encountered due to mechanical systems, insulation, or other factors.
Additionally, ExoAir 230 is air and water resistant, offering protection against air infiltration and water penetration while remaining permeable to water vapor. This combination of properties helps to maintain a balanced building envelope, reducing the risk of thermal bridging and improving overall energy efficiency.
Relevance to U.S. Building Standards and Projects
In the United States, building codes and standards such as the International Building Code (IBC) and ASHRAE 90.1 place increasing emphasis on the performance of building envelopes, including air and vapor barriers. ExoAir 230 aligns with these standards by providing a solution that supports energy efficiency, fire safety, and long-term durability.
One of the key applications of ExoAir 230 is in multi-story commercial buildings where compliance with NFPA 285 is required. This standard is particularly relevant for buildings with non-load-bearing exterior walls and combustible materials, as it evaluates the ability of the wall assembly to prevent the spread of fire and smoke between floors.
The product has been used in various high-profile projects, including the Maynard H. Jackson Jr. International Terminal in Atlanta, which was projected to accommodate 13 million passengers annually. The terminal’s design required an air barrier that could meet both performance and compliance standards, and ExoAir 230 was selected for its ability to deliver these attributes while supporting the building's long-term operational needs.
Integration with Building Systems and Materials
For air barriers to function effectively, they must integrate seamlessly with other building systems and materials. ExoAir 230 is designed to be compatible with a wide range of substrates and construction materials, including concrete, masonry, metal, and various types of insulation. This compatibility ensures that the air barrier can be applied directly to the building’s structural elements without the need for additional primers or coatings.
The documentation also highlights the importance of continuity in the air barrier system, emphasizing that all seams, joints, and penetrations must be properly sealed to prevent air leakage. This is particularly important in areas such as roof-wall transitions, window and door openings, and penetrations for mechanical systems.
To ensure continuity, it is recommended to follow manufacturer guidelines for overlapping and sealing joints. These guidelines typically specify the minimum overlap widths and the use of compatible sealants or tapes to reinforce connections between sections of the air barrier.
Maintenance, Durability, and Long-Term Performance
One of the key advantages of ExoAir 230 is its long-term durability and resistance to environmental stressors. The product is designed to remain stable and functional for the life of the building, with minimal degradation due to exposure to UV light, temperature fluctuations, or moisture. This reduces the need for maintenance and reapplication, making it a cost-effective solution for commercial building envelopes.
The documentation does not provide specific information on the expected service life of the material in different climates or under various conditions. However, it does emphasize the importance of proper installation and surface preparation as key factors in ensuring long-term performance.
For ongoing maintenance, it is recommended to periodically inspect the air barrier for signs of damage, such as cracking, peeling, or delamination. Any defects should be repaired promptly using compatible materials to maintain the integrity of the barrier.
Conclusion
ExoAir 230 is a high-performance fluid-applied air barrier designed for use in commercial building applications. It offers a unique combination of air and water resistance, vapor permeability, and UV and temperature tolerance, making it a versatile option for a wide range of construction projects. Its compatibility with various substrates and application methods further enhances its utility in different environments and project types.
When selecting an air barrier for a commercial building, it is essential to consider factors such as climate, fire performance, and project-specific requirements. ExoAir 230 aligns with these considerations, offering a solution that supports compliance with key building standards such as NFPA 285 and ASHRAE 90.1. Its application methods—roller, sprayer, and trowel—provide flexibility in installation, while its long-term durability ensures continued performance over the life of the building.
For professionals involved in commercial construction, ExoAir 230 represents a reliable and effective option for air barrier systems. By following manufacturer guidelines for application and integration with other building materials, it is possible to achieve a high-performance building envelope that meets both functional and regulatory requirements.