ASTM E783 – Field Measurement of Air Leakage Through Installed Exterior Windows and Doors
ASTM E783 is the industry standard for field measurement of air leakage through installed fenestration systems, including windows, doors, curtain walls, and storefronts. Unlike laboratory tests such as ASTM E283, which evaluate air infiltration under controlled conditions, E783 is performed in situ, within the actual built environment. The procedure is widely used in quality assurance and post-installation compliance verification.
However, the test has critical limitations, particularly when applied to portions of continuous window wall and curtain wall systems. The standard was originally designed for discrete window and door units installed in wall assemblies—not for large, continuous glazing systems that lack defined perimeters. Misapplication of ASTM E783 has led to significant industry-wide misunderstandings and erroneous conclusions regarding building envelope performance. To read more about these limitations, download the full paper: ASTM E783 and All-Glass Facades .
A sealed test chamber is mounted on the interior or exterior face of the fenestration system, isolating the specimen from surrounding air paths. The chamber must be securely sealed to prevent or minimize extraneous air leakage that could skew test results.
A controlled static pressure differential is applied across the test specimen using a calibrated blower system. The blower exhausts air from or introduces air into the sealed chamber to generate an interior/exterior pressure differential. Typical pressure differentials range from 75 to 300 Pascals (Pa), with project specifications often dictating test pressures.
One often-overlooked but critical aspect of ASTM E783 testing is the need to correct raw airflow measurements based on the localized air density at the time of testing. Since the volumetric flow rate measured in the field varies with temperature, barometric pressure, and altitude, all results must be converted to Standard Cubic Feet per Minute (SCFM) to ensure accuracy and consistency across different test environments.
Why Localized Air Density Matters
Best Practices for Accurate Air Density Measurement
By ensuring proper air density measurement and SCFM conversion, ASTM E783 test results can provide relatively accurate assessments of air infiltration & exfiltration performance. Neglecting this critical step can lead to misleading conclusions, flawed compliance assessments, and disputes over test validity.
^ Back to TopASTM E783 is a building envelope performance measurement tool, utilized widely across the construction industry, but its application to large-scale glazed systems—such as continuous window walls and curtain walls—presents fundamental challenges that can lead to misleading results.
Curtain walls and window walls often feature continuous receptor cavities and stack joints that create air pathways between adjacent units. In an uncompartmentalized system such as this, an ASTM E783 test chamber may inadvertently draw air from these interconnected spaces rather than from the exterior environment.
Consequence: The test overestimates or misattributes air infiltration, leading to erroneous conclusions about envelope performance. A system may appear to pass when, in reality, it is experiencing substantial uncontrolled airflow.
A common workaround involves applying tape to interior gaskets, operable vent perimeters, and frame joints to artificially compartmentalize the test specimen. This "tare tape" method aims to eliminate extraneous leakage but often fails to fully account for air movement through frame joinery, receptor weeps, and mullion reveals.
Consequence: This approach misrepresents the air tightness of the actual installed system, producing test results that do not reflect real-world performance.
Example: If a curtain wall system has hidden air pathways in its frame receptors, sealing a small portion with tape does not prevent leakage elsewhere in the system. The test may register an artificially low air infiltration rate, leading stakeholders to incorrectly conclude that the façade is airtight.
Some project teams incorrectly rely on ASTM E783 results to predict overall building air infiltration rates and derive energy usage estimates.
Consequence: ASTM E783 does not provide a whole-building air leakage measurement and should not be used as the sole method for evaluating overall envelope performance. Building owners relying solely on ASTM E783 may face unexpected energy losses and uncontrolled airflow issues despite having "passing" test reports.
Example: If a curtain wall system has hidden air pathways in its frame receptors, sealing a small portion with tape does not prevent leakage elsewhere in the system. The test may register an artificially low air infiltration rate, leading stakeholders to incorrectly conclude that the façade is airtight.
Industry Example: Many high-rise buildings with multiple passing ASTM E783 test reports have later experienced:
This underscores why ASTM E783 should be used only as a tool for evaluating localized fenestration performance—not as a predictor of whole-building air tightness.
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For a deeper examination of ASTM E783's limitations and misapplications, Hightower Labs has published a technical document detailing industry-wide challenges with this test method. This report outlines how improper test setups and flawed interpretations can lead to critical performance misjudgments.
Click here to download the full paper: ASTM E783 and All-Glass Facades .
^ Back to TopIndependent studies, industry papers, slideshows, video presentations, and other content benefiting those in the industry with the patience to read five pages, and diagrams for the developers.
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