​In August of 2020, ThermalWise conducted a whole building air leakage test on the Stratford Emergency Services Facility (ESF) in Stratford, PEI. The purpose of the test was to verify the rate of whole building air leakage as a comparison to the project specified air leakage rate. 

​Air leakage is the unintended movement or flow of air through a building envelope. It is driven by either positive (infiltration) and negative (exfiltration) pressure differences across the envelope (ASTM E779). This unintended flow of air contributes to the building’s heat and cooling loads and can affect occupant comfort, indoor environmental quality, and material/product durability. 

​Building air leakage is generally specified and reported as an air leakage rate. An air leakage rate is defined as “…the volume of air movement/unit time across the building envelope including airflow through joints, cracks, and porous surfaces, or a combination thereof driven by mechanical pressurization and de-pressurization, natural wind pressures, or air temperature differentials between the building interior and the outdoors, or a combination thereof.” (ASTM E779).   

​A building’s air leakage rate can be measured through air leakage testing. Air leakage testing is the process of inducing and measuring pressure differentials across the building envelope using a mechanical system or fans and measuring the air flow required to reach and maintain the pressure differences. Using this data, a mathematical relationship is established between the pressure differential and air flow across the building envelope (i.e. air leakage). 

​For the Stratford ESF project, ThermalWise conducted air leakage testing for the Administrative Area in general accordance with the ASTM E779 Standard Test Method for Determining Air Leakage Rate by Fan Pressurization. This testing standard is widely used to test new construction and major retrofit building projects for air leakage.

ThermalWise conducted two whole building air leakage tests (WBALTs) at the Wing Telecommunications Upgrade and Information Services Upgrade Personnel and Shops Facility (PSF) at CFB Shearwater, Nova Scotia. The purpose of the testing was to verify the whole building air tightness functional performance against project specifications at two stages of construction – completion of the air barrier system; and at or near construction completion.

ThermalWise completed air tightness testing and air leakage site detection using thermographic imaging at two stages of construction. The first stage was conducted once all building envelope components were installed. The second stage was performed after all building components were in place and construction completed.

 General Air Tightness Testing Procedure (based on subsection 3.1.1 and 3.1.2 of section 07 27 00): the mean value of the air leakage flow through the exterior envelope for a negative and positive pressurization air leakage test must not exceed 0.25 CFM/ft2 @75Pa. Air leakage testing is required to be performed in general accordance with ASTM E779 with additional requirements included in the construction specification. 

 Building Air Leakage Site Detection: thermography-based air leakage site detection took place in conjunction with the air leakage testing for both Stage 1 and Stage 2 testing. This testing was performed in general accordance with ASTM 1186. 

Thermal Wise completed one whole building air leakage test (WBALT) to evaluate the constructed air tightness of the building in question. The test provided the client with the following metrics: air changes per hour at 50 Pa, normalized air leakage rate at 75 Pa (can be used to compare results to default code air leakage rates) and the flow exponent for the test(s) conducted. Testing was conducted in general compliance with ASTM E3158, “Standard Test Method for Measuring the Air Leakage Rate of a Large or Multizone Building.”