As energy codes continue to advance in Washington State, the demand for accurate building envelope testing in Seattle has never been higher. Modern commercial projects must meet strict airtightness requirements to comply with the Seattle Energy Code, IECC, and ASHRAE 90.1. One of the most reliable ways to verify compliance is through a whole building pressurization test. At QED Lab, we specialize in delivering accurate, code compliant testing that helps builders avoid delays, improve energy performance, and document airtightness with confidence. Understanding how the test works is the first step in ensuring your project meets all required standards.
What a Whole Building Pressurization Test Measures
A whole building pressurization test measures how much air leaks through the building envelope by using calibrated fans to create a controlled pressure difference between the inside and outside of the structure. The goal is to quantify air leakage in a consistent and repeatable way so owners, builders, and code officials can verify that the building is sealed to required levels. In Seattle, these tests are commonly needed for both new construction and major renovations where energy performance and air barrier continuity are required by code.
Standards Used in Building Envelope Testing
Whole building tests for commercial buildings follow several industry standards, with ASTM E779 in Seattle being the most widely recognized for fan pressurization testing. ASTM E1827 in Seattle may also be used for smaller buildings or for alternative test methods. ASTM E1186 in Seattle is commonly used for air leakage detection and diagnostic inspection to identify problem areas before a final quantitative test is performed. Local jurisdictions, including Seattle, typically reference these standards and align them with the energy code provisions found in IECC and ASHRAE 90.1, both of which outline acceptable air leakage limits and compliance pathways.
How the Testing Process Works
During a whole building pressurization test in Seattle, the testing team begins by preparing the building to match code requirements. Exterior doors and windows are closed, interior doors are opened, and mechanical openings are sealed according to the test standard. Once the building is ready, calibrated fan systems are installed in selected door openings. These fans increase or decrease pressure inside the building, usually to 75 Pascals, and sensors record how much air flows through the fans to maintain that pressure. The total airflow required is a direct measurement of the building’s air leakage.
The test produces multiple data points at increasing pressure levels. These points are plotted and analyzed to determine the building’s air leakage rate, usually expressed as cfm per square foot of envelope area at 75 Pascals. In Seattle, many commercial projects must meet specific targets for air leakage to comply with the Seattle Energy Code or the ASHRAE 90.1 compliance path. When a building meets or exceeds these targets, it confirms a well performing air barrier system that supports energy efficiency, indoor comfort, and HVAC performance.
Using Diagnostic Tools During Testing
A major benefit of performing a whole building pressurization test is the ability to identify air leakage locations during the process. While the quantitative test measures total leakage, qualitative testing can occur alongside it using smoke pencils, infrared thermography, or tracer smoke to pinpoint gaps, cracks, and missed air barrier connections. Many Seattle builders use QED Lab early in construction to perform diagnostic envelope testing so problems can be corrected before surfaces are concealed. This reduces the risk of failing the final test and improves overall building performance.
Why Whole Building Testing Matters in Seattle
For commercial builders, architects, and owners in Seattle, whole building pressurization testing is more than a code requirement. It is a quality assurance process that confirms the envelope performs as designed. Buildings that achieve low air leakage rates benefit from reduced energy loss, improved HVAC efficiency, enhanced moisture control, and better indoor air quality. As Seattle continues to lead the region in energy efficient building practices, these tests are becoming standard on commercial projects of all sizes.
QED Lab’s Role in Seattle Building Envelope Testing
QED Lab provides whole building pressurization testing in Seattle with certified technicians, calibrated equipment, and full documentation that meets ASTM, IECC, and ASHRAE 90.1 requirements. Whether your project needs diagnostic testing, final compliance testing, or complete building envelope testing in Seattle, our team ensures your building meets performance targets with accuracy and professionalism.