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This page contains information on air barriers and the codes and standards associated with them. It includes the testing requirements for air barriers for air permeance, air leakage, and fire resistance, including use of air barriers in NFPA 285 assemblies, as well as updated information about air barrier requirements in national codes and standards.
- Intro
- List of Code Requirements for Air Barrier Materials
- ASHRAE 90.1 – 2010: Energy Standard for Buildings Except Low-Rise Residential Buildings
- ASHRAE 189.1: Standard for the Design of High Performance, Green Buildings
- International Energy Conservation Code
- International Building Code
- International Green Construction Code
- Explanation Regarding Standards
- ASTM E 2357: Standard Test Method for Determining Air Leakage of Air Barrier Assemblies
- Fire Testing
- ASTM E 84
- NFPA 285
- W. R. MEADOWS Air Barrier Materials
With the continued rise in energy costs and the concentrated design of structures that are more energy efficient, the industry has continued to revise codes and standards to provide minimum requirements that need to be met. Significant changes in the 2012 International Building Code (IBC), 2012 International Energy Conservation Code (IECC), and ASHRAE 90.1-2010 now require the design of buildings to not only have increased thermal efficiency with the use of continued insulation, but also require the use of a complete air barrier system to address air leakage. Currently, any code that makes reference to any of these documents require a complete air barrier system to be included as part of the building enclosure.
Also to be noted is the fact that due to the increased use of foam insulation in non-combustible type construction, there has been a requirement for the industry to develop standards to address the use of combustible materials in these types of construction. As a result of this, the IBC has included requirements for assembly fire testing since 1998. Continued concern for fire safety has now driven additional assembly requirements that now include water resistive barriers (WRBs) to be part of the wall assembly testing.
In addition, other industry documents that are referenced within code and support the construction of energy-efficient structures also require the use of a complete air barrier system. These include ASHRAE 189.1, IgCC and the newly released LEED version 4, which does not contain specific air barrier requirements, but does make reference to ASHRAE 90.1-2010 which, as stated above, contains air barrier requirements.
As there have been a number of significant changes in the last couple of years, it is important that there is an understanding of what each of these requirements are. To support this, it is also essential that there is an understanding of how these requirements are to be met in order to select an air barrier material that can be used as part of a code-compliant air barrier system.
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To contact your local W. R. MEADOWS representative or for general correspondence, please click here. If you need immediate assistance, please call (800) 342-5976. Thank you!
LIST OF CODE REQUIREMENTS FOR AIR BARRIER MATERIALS
Within all of these documents, there are explanations about the fact that the building envelope shall be designed and constructed with a continuous air barrier. Also included are stipulations that define how this is to be met, including statements relating to the detailing of joints, interconnections, and penetrations; the continuity of the air barrier over all surfaces; and that it shall be designed to resist the positive and negative pressures for wind, stack, and mechanical ventilation. In addition, there are specific air-permeance and air-leakage requirements listed, as stated below.
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ASHRAE 90.1 – 2010: Energy Standard for Buildings Except Low-Rise Residential Buildings
This standard provides minimum requirements for energy-efficient designs for buildings, except for low-rise residential buildings. Not only does this include new buildings and their systems, but it also includes additions to buildings along with their systems and new systems and equipment in existing buildings
Materials: Must have an air permeance not exceeding 0.004 cfm/ft.2 under a pressure differential of 0.3 in. w.g.(1.57 psf) when tested in accordance with ASTM E 2178.
Assemblies of materials and components: Must have an average air leakage not to exceed 0.04 cfm/ft.2 under a pressure differential of 0.3 in. w.g.(1.57 psf) when tested in accordance with ASTM E 2357.
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ASHRAE 189.1: Standard for the Design of High Performance, Green Buildings
This standard provides a complete package for the design, construction, and operation of green buildings, both new and remodelled, and serves as a compliance option in the 2012 International Green Construction Code (IgCC). It includes such aspects as site sustainability, water-use efficiency, energy efficiency, indoor environmental quality, and the impact of the building on atmosphere, materials, and resources.
Materials: Must have an air permeance not exceeding 0.004 cfm/ft.2 under a pressure differential of 0.3 in. w.g.(1.57 psf) when tested in accordance with ASTM E 2178.
Assemblies of materials and components: Must have an average air leakage not to exceed 0.04 cfm/ft.2 under a pressure differential of 0.3 in. w.g.(1.57 psf) when tested in accordance with ASTM E 2357.
International Energy Conservation Code
This standard was created in 2000 and sets sets minimum energy-efficiency requirements for both residential and commercial buildings.
Within Chapter 4: Commercial Energy Efficiency, the following requirements are listed.
Materials: Must have an air permeance not exceeding 0.004 cfm/ft.2 under a pressure differential of 0.3 in. w.g. (1.57 psf) when tested in accordance with ASTM E 2178.
Assemblies of materials and components: Must have an average air leakage not to exceed 0.04 cfm/ft.2 under a pressure differential of 0.3 in. w.g. (1.57 psf) when tested in accordance with ASTM E 2357.
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International Building Code
The IBC provides minimum standards of construction used to regulate construction through the use of standards ensuring public safety, health, and welfare both during and after occupancy. It was established to consolidate a number of building codes into one code that could be used nationally.
Although not directly making reference to air barrier materials and assembly requirements within the IBC, in Chapter 13: Energy Efficiency, the code states that “Buildings shall be designed and constructed in accordance with the International Energy Conservation Code.” Therefore, the requirements listed in Chapter 4 of the IECC would be required.
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International Green Construction Code
The IgCC is the first model code to include sustainability measures for the entire construction project and its site — from design through construction, certificate of occupancy, and beyond. The new code is expected to make buildings more efficient, reduce waste, and have a positive impact on health, safety, and community welfare.
It states within this code that a continuous air barrier shall be provided in accordance with Section C402.4.1 of the International Energy Conservation Code, which is, as stated above, regarding air barrier materials and assemblies.
Within a number of these standards and codes, there is also a requirement for testing of the completed building according to ASTM E 779 (or an equivalent, approved method). The requirement is that the air leakage rate of the building envelope does not exceed 0.4 cfm/ft.2 under a pressure differential of 0.3″ water (1.57 lb./ft.2) (2.0 L/s·m2 under a pressure differential of 75 Pa). Using materials and assemblies that meet the air permeance and air-leakage requirements constructed in such a way as to provide a continuous air barrier system makes this attainable.
EXPLANATION REGARDING STANDARDS
ASTM E 2178: Standard Test Method for Air Permeance of Building Materials
The purpose of this test is to measure the air permeance of flexible sheet or rigid panel-type materials. This is the amount of air that passes through them. This is important to differentiate from air leakage which is the air that passes through holes or gaps. The requirement that is defined in most codes and standards is that the air barrier material must have an air permeance of less than 0.02 L/(s • m2) @ 75 Pa (0.004 cfm/ft.2 @ 1.57 lb./ft.2). This defines the maximum allowable air leakage for a material that can be used as part of the air barrier system.
Figure 1: Reprinted, with permission, from ASTM E2178-13: Standard Test Method for Air Permeance of Building Materials, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.
Figure 2: Air permeance apparatus for testing to ASTM E2178. Credit: Architectural Testing, Inc.
The test method includes the testing of a 1 m x 1 m air barrier specimen using an apparatus similar to the following (Figure 1, Figure 2). This specimen is then subjected to various pressure differentials with the intent of determining an assigned air-permeance rate of the material at the reference pressure difference (ΔP) of 75 Pa.
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ASTM E 2357: Standard Test Method for Determining Air Leakage of Air Barrier Assemblies.
This test method involves the testing of two wall assemblies that are deemed to be a worst-case scenario, as stated within the standard. Typically for most assemblies, this has been steel-stud construction with exterior gypsum board sheathing. The first of these assemblies is an 8′ x 8′ wall where the joints are sealed and the air barrier is applied to form a continuous assembly. The joint treatment and air barrier application is according to a manufacturer’s instructions (Figure 3, Figure 4). The second is an 8′ x 8′ wall with a 24″ x 48″ window rough opening, masonry ties, junction boxes, galvanized duct, and a PVC pipe. The panel joints and penetration joints are sealed and the air barrier material then applied, again according to the manufacturer’s instructions (Figure 5, Figure 6). Testing for air leakage is performed initially at a number of different pressures, both under positive and negative pressure differentials. The assembly is then subjected to pressure loading (sustained, cyclic, and gust loading) and then inspected for any assembly integrity problems. Following this conditioning, the air leakage is again performed as previously tested. The cumulative results of this test will include the air permeance of the material, accessories, air barrier components (window and services elements), and the air leakage that results from joining those three parts together.The code requirements when tested to this standard is that the air barrier assembly must have an air leakage of less than 0.2 L/(s • m2) @ 75 Pa (0.04 cfm/ft.2 @ 1.57 lb./ft.2).
Figure 3: Reprinted, with permission, from ASTM E2357-11: Standard Test Method for Determining Air Leakage of Air Barrier Assemblies insert ASTM standard designation number and title, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.
Figure 4: Photos of opaque wall (with and without material applied) included in ASTM E2357 standard test method.
Figure 5: Reprinted, with permission, from ASTM E2357-11: Standard Test Method for Determining Air Leakage of Air Barrier Assemblies insert ASTM standard designation number and title, copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org.
Figure 6: Photos showing wall assembly with rough opening and penetrations (with and without material applied) used for ASTM E2357.
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FIRE TESTING
A fire test is a means of determining whether or not fire-protection products meet minimum performance criteria as set out in a building code or other applicable legislation. The IBC makes reference to ASTM E 84: Standard Test Method for Surface Burning Characteristics of Building Materials, as well as one that has become more recognized recently, NFPA 285: “Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-Load Bearing Wall Assemblies Using the Intermediate Scale Multistory Apparatus.”
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ASTM E 84
This test is also referred to as the “Steiner Tunnel” test which was developed in the U.S. in 1943 and, throughout the years, has become a widely adopted standard throughout the U.S.
This test method incorporates a 25′ by 20″ chamber with a gas burner that is lit at one end of the tunnel, which is then exposed to a forced draft at the burner end, allowing for the flame to spread along the specimen. In addition, the amount of smoke is measured in the exhaust duct of the tunnel (Figure 7). The duration of the test is 10 minutes and the distance the flame spreads is then measured. The flame-spread index (FSI) is then calculated based on the distance and rate of time and then compared to the flammability of an inert board and red oak, which have a flame-spread index of 0 and 100 respectively. A similar calculation is performed for smoke development. The IBC calls for materials to achieve a Class A rating based on this test, which means the flame-spread index must be less than 25 and the smoke development index (SDI) must be less than 450.
Figure 7: Steiner Tunnel for testing to ASTM E84. Credit: Architectural Testing, Inc.
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NFPA 285
This standard was developed by the National Fire Protection Agency (NFPA), an international non-profit organization established in 1896. Their mission is to reduce the worldwide burden of fire and other hazards on the quality of life by providing and advocating consensus codes and standards, research, training, and education.
In 1998, the NFPA developed a standard, NFPA 285, which is a test method designed to determine the flammability characteristics of exterior, non-load-bearing wall assemblies/panels that contain foam plastic insulation. Foam plastic insulation can consist of open and closed cell spray polyurethane foams, extruded polystyrene, expanded polystyrene, rigid board stock, or polyisocyanurate products. The intent of this test method is to evaluate the inclusion of combustible components within wall assemblies/panels that are required to be of non-combustible construction. It is intended to simulate the multistory flammability fire performance of entire exterior wall assemblies. This was added to the 2000 IBC and has been referenced within the IBC ever since. A revision to the IBC in 2012 now includes that water-resistive barriers (including air barriers) are required to be including in NFPA 285 approved wall assemblies. Prior to that, the 2009 IBC required only that these materials achieve a Class A flame spread and smoke development rating according to ASTM E84.
The IBC contained NFPA 285 requirements in the 2006 and 2009 editions, Chapter 26, requiring that wall assemblies containing foam plastic insulation pass NFPA 285 Additional requirements for NFPA 285 were added to the 2012 IBC, which now requires that exterior wall assemblies greater than 40′ in height for Type I, II, III, and IV construction containing combustible water resistive barriers must pass NFPA 285.
As stated previously, Chapter 13 of the 2012 IBC states that buildings shall be designed and constructed in accordance with the International Energy Conservation Code (IECC). The IECC states that “a continuous air barrier shall be provided throughout the building thermal envelope” and since the air barrier typically functions in a wall assembly as the water-resistive barrier, this then becomes part of an assembly that is required to pass NFPA 285. All components within this assembly must perform in such a way that the assembly meets the passing criteria. Fire testing of individual materials, such as ASTM E84, although important test information, does not mean when combined, they will pass NFPA 285.
Figure 8: ISMA chamber for testing to NFPA 285. Credit: Architectural Testing,
What does it involve?
The NFPA 285 testing apparatus is a two-story wall assembly that includes a framed window opening on the first floor.
The pass/fail criteria is that flame propagation does not occur either vertically or laterally beyond an acceptable distance from the area of flame plume impingement on or within the wall assembly. Thermocouples are placed throughout the wall and the defined temperature limits cannot be exceeded, otherwise the test is considered a failure.
- No flame propagation in second-floor room.
- The inside wall assembly thermocouples shall not exceed 1000o F during the 35-minute test.
- Externally flames shall not reach 10′ above the top of the window.
- Externally flame shall not reach 5′ laterally from the center line of the window.
Following is a flowchart that helps to explain whether or not the assembly is required to be tested to NFPA 285:
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W. R. MEADOWS® manufactures a full line of air barrier materials that have been independently tested using ASTM E 2178 and ASTM E 2357, the industry-accepted air permeance and air leakage standards. All the materials listed below exceed the air barrier requirements listed in codes and standards. In addition, a number of our fluid-applied air barriers have been tested to meet the Class A requirements of ASTM E 84 and judged to be used in NFPA 285 compliant wall assemblies*.
AIR-SHIELD self-adhesive air/vapor and liquid moisture barrier is a part of a total system to complete the building envelope. It is a roll-type product that is nominally 40 mils thick protected by a special release paper. It remains flexible when surface mounted and will adhere to most primed surfaces at minimum temperatures of 40° F (4° C). [A low temperature version for applications between 20° F (-7° C) and 60° F (16° C) and an extra low temperature version for applications between 0° F (-18° C) and 60° F (16° C)] is also available.
AIR-SHIELD LM a liquid-applied, water-based, polymer-modified air/vapor and liquid moisture barrier. AIR-SHIELD LM cures to form a tough, seamless, elastomeric membrane, which exhibits excellent resistance to air and moisture transmission.
AIR-SHIELD LMP is a single-component, liquid-applied, vapor permeable air/liquid moisture barrier. AIR SHIELD LMP stops the movement of air, while at the same time, allows the passage of vapor. The product is designed for wall assemblies that require a vapor-permeable air barrier. For situations where the air barrier is to be left exposed for an indefinite period, such as beneath rain screen panels, a black version is also available.
AIR-SHIELD LSR is an asphalt-free, single-component, synthetic, rubber-based liquid air/vapor and liquid moisture barrier. AIR-SHIELD LSR cures to form a tough, seamless, elastomeric membrane, which exhibits excellent resistance to air and moisture transmission.
*For information regarding the specifics of the testing and the assemblies, please contact W. R. MEADOWS Technical Services.
Request More Information
To contact your local W. R. MEADOWS representative or for general correspondence, please click here. If you need immediate assistance, please call (800) 342-5976. Thank you!