Air barrier assemblies that have not been evaluated in accordance with CAN/ULC-S742, “Standard for Air Barrier Assemblies – Specification”, must nevertheless provide the air leakage performance required for the selected Performance Class. Field testing may be required to verify their performance.
Field assessment of the air leakage characteristics of both the primary air barrier assemblies and the connections between adjacent air barrier assemblies can be a useful tool in establishing whether the acceptable minimum performance level is met.
Field testing of installed air barrier assemblies can be conducted in accordance with test standards such as
- ASTM E783, “Standard Test Method for Field Measurement of Air Leakage Through Installed Exterior Windows and Doors”, and
- E1186, “Standard Practices for Air Leakage Site Detection in Building Envelopes and Air Barrier Systems”.
Even though some test standards are intended for specific types of air barrier assemblies (e.g., windows and doors), the test methodology used to assess air leakage rates may be acceptable for use with other types of air barrier assemblies. However, with this approach, it is important to establish rational acceptance criteria that reflect the test methodology and the types of air barrier assemblies being tested.
Qualitative testing can be used to identify locations in air barrier assemblies where air leakage is occurring so that field repairs can be made to improve the assembly’s airtightness performance. ASTM E1186 provides guidance on a number of approaches for identifying locations of air leakage, including the following:
- infrared scanning,
- smoke tracer observation,
- airflow measurement,
- sound detection,
- tracer gas detection, and
- liquid leak detection.
Each of these techniques has benefits and limitations, as described in the standard. The most suitable approach for a particular situation is selected by the testing agency on the basis of their experience in relation to the type of construction being assessed and the weather conditions at the time of testing. Regardless of the approach selected, the testing of air barrier assemblies must be properly coordinated with the construction process so that any air leaks identified can be addressed without adversely affecting progress.