Traditionally, testing a building’s air barrier or air control layer has been done using artificial pressure created by a fan, commonly referred to as a blower door test. The advantage of air pressure–differential testing is twofold. First, it quantifies the building tightness—measuring it at CFM50, ACH50 or CFM/sq. ft. of surface area. Second, it locates deficiencies in the air barrier.

When conducting a blower door test, technicians look for fluttering drapery (and spiderwebs) and use synthetic smoke and thermal cameras to detect leaks. With a manometer, they measure pressure differentials between spaces inside the building enclosure.

The blower door method’s drawback is the need for a continuous, or close-to continuous, air barrier. The air control layer needs to be near complete to reach the 50 Pascals of pressure the test requires for accurate results. You can check for air leaks using lower pressures, but if you’re setting up the equipment, it’s best to perform a full test, which includes the air leakage rate. Another disadvantage is having to set up a blower door for testing individual assemblies—for example, checking for air leakage in a single window or door or retesting an assembly that previously failed.

A second way to test for air leaks

Recently, I have learned about equipment that identifies air leaks without the need for a pressure differential. It’s called ultrasonic airtightness testing, and it uses sound waves to identify leakage areas. The equipment I use is from British manufacturer Coltraco. They produce equipment for monitoring the watertight integrity of ships and offshore platforms, among other applications.

Coltraco’s Portascanner Airtight and the more basic Portascanner—which is the model I am using—was developed during COVID, when the need for testing of airtight enclosers in hospitals and other healthcare facilities was critical.…