To properly specify air barriers it’s important to understand all aspects of the air barrier system. In particular the materials, components, accessories, and assemblies must be clearly defined within the specification so that a proper bid and submittal is received. The following definitions have been provided by the Air Barrier Association of America Inc. and are provided below to familiarize the construction community with the proper terms:
Air barrier accessory: Products designated to maintain air tightness between air barrier materials, air barrier assemblies and air barrier components, to fasten them to the structure of the building, or both (e.g., sealants, tapes, backer rods, transition membranes, nails/washers, ties, clips, staples, strapping, primers).
Air barrier material: Building material with an air permeance not greater than 0.02 L/(s·m²) at 75 Pa that is designed and constructed to provide the primary resistance to airflow through an air barrier assembly.
Air barrier assembly: Combination of air barrier materials and air barrier accessories that are designated and designed within the environmental separator to act as a continuous barrier to the movement of air through the environmental separator.
Air barrier component: Pre-manufactured elements such as windows, doors and service elements that are installed in the environmental separator.
Air barrier system: Combination of air barrier assemblies and air barrier components, connected by air barrier accessories that are designed to provide a continuous barrier to the movement of air through an environmental separator.
Environmental separator: Parts of a building that separate the controlled interior environment from the uncontrolled exterior environment, or that separate spaces within a building that have dissimilar environments.
Air barrier manufacturer: Corporation which manufactures air barrier materials, components and / or assemblies. The manufacturer shall declare whether their product is a material, a component or an assembly.
Air leakage rate: Rate of airflow (L/s) driven through a unit surface area (m²) of an assembly by a unit static pressure difference (Pa) across the assembly (see also ASTM E 2357)
Air permeance: Rate of airflow (L/s) through a unit area (m²) of a material driven by unit static pressure difference (Pa) across the material (see also ASTM E 2178).
Design service life: Service life specified by the designer according to the expectations (or requirements) for the air barrier material (see also CSA-S478).
Service life: Period of time during which the air barrier assembly or any of its materials or accessories performs without unforeseen costs or disruption for maintenance or repair.
Knowing and understanding these terms will help ensure that the air barrier is properly specified and that the Project is bid accurately.
Contact the air and vapor barrier experts at Carlisle Coatings & Waterproofing for project specific questions, details and applications guidance. They may be reached at 888-229-2199 or firstname.lastname@example.org .
For straight-forward information about how new wall assemblies containing plastic foam insulation and combustible weather barriers can meet tough new NFPA 285 standards, please visit fireresistccw.com.