Air Leakage Testing
Whole building air leakage testing is a quantitative test method that measures the air infiltration of a building after it has been completely enclosed and finishes have been installed. It’s commonly known as blower door testing because the fans are often placed in an open door frame. It’s also referred to as air barrier testing; most likely because the testing is often called for under the "07” section of the U.S. Army Corps of Engineers (USACE) specifications, under “Air Barrier.” The fans used for this testing are calibrated to measure air flow.
Air leakage testing is typically required if a project has USACE or similar specifications (such as NAVFAC, NASA, and AFCEC). While this testing isn’t inexpensive, a savvy commercial building owner may still require it up front to act as an incentive for the General Contractor to provide an air tight building. In addition to commercial building applications, institutional owners such as universities and hospitals may also have an interest in this type of testing. There is a correlation between a building that has a low air infiltration and lower operational costs. Especially in a larger facility, the cost of the test can be offset by money saved over the long term.
A common deficiency that leads to excessive air leakage is discontinuous sections of the air barrier layer in the exterior walls. These discontinuities can often occur during construction when the manufacturer’s installation instructions are not strictly followed or unexpected as-built conditions occur. Even if the construction documents and manufacturer instructions are followed, these materials are sensitive to damage from adjacent construction activity. Careful consideration of detailing during preconstruction, combined with a strong QC/QA program can drastically reduce the occurrence of these issues.
Even if the air barrier material is expertly installed, the interface between the exterior wall system and other systems can represent a vulnerability to air infiltration. The windows and doors have a significantly lower resistance to air infiltration and the sealant joints around the windows also present vulnerability. Careful consideration of the transition details between systems is required to address this type of vulnerability.
Preconstruction review of the air barrier details by a third party specialist familiar with issues pertinent to air barrier installation can identify issues early in the process. Waterproofing, roofing, air barrier and other building envelope trades should provide shop drawings as part of the submittal process so that the details from these different trades are considered and coordinated. Air barrier installers should be accredited by the Air Barrier Association of America (AABA).
Qualitative testing (ASTM E1186) should be considered and specified during construction to diagnose issues in mock-ups and in production. Such testing visually identifies air leakage locations using tracer gas. Another qualitative testing method is using infrared imaging to locate discontinuities in building insulation.
We hope this Lessons Learned has been helpful. If you would like to learn more, please contact your nearest ECS office.
ECS Corporate Services, LLC