Currently, there are default codes and standards in place. The following list of documents provides what is currently available as reference and guidance for the design, specification, installation, and testing of air barriers:
In the U.S.:
- International Building Code (IBC)
○ Exterior Walls Chapter 14 IBC
○ Weather Protection IBC 1402.2
○ Vapor Retarders IBC 1404.3
○ Flashing IBC 1404.4
- ASTM E2178-21a, Standard Test Method for Determining Air Leakage Rate and Calculation
of Air Permeance of Building Materials - ASTM E2357-18, Standard Test Method for Determining Air Leakage Rate of Air Barrier Assemblies
In Canada:
- National Building Code of Canada (NBC)
○ Provincial building codes
○ Part 9—Small buildings
○ Part 5—Environmental separation
- CAN/ULC-S741-08(R2020)—STANDARD FOR AIR BARRIER MATERIALS—SPECIFICATION
- CAN/ULC-S742:2020—STANDARD FOR AIR BARRIER ASSEMBLIES—SPECIFICATION
Demand for resilient WRABs
The CAN/ULC-S741 and CAN/ULC-S742 standards are interesting as they are much better at evaluating both a material and an assembly’s ability to perform to ultimate limits under more realistic environmental conditions than the ASTM test methods alone. CAN/ULC-S741 and CAN/ULC-S742 rely highly upon the ASTM methodology, but have improved upon the context in which it is performed. This can assist designers and specifiers in comparing systems to better understand and select the appropriate WRAB for their project. These improvements in standards are most welcomed, but if to be fully prepared to meet the challenges of a changing climate, it is important to ensure what is specified in design is achievable and verifiable where it matters most, which is, in the built environment.
