Large Building
Blower Door
Testing
Multi-fan air leakage testing for new and existing commercial and multifamily facilities of any size. ASTM E779 and E1827 compliant.
2021 IECC Compliance Testing
The 2021 International Energy Conservation Code (IECC) establishes mandatory air leakage testing requirements for new large commercial buildings. Under Section C402.5, buildings exceeding 25,000 sq ft of conditioned floor area must demonstrate a maximum whole-building air leakage rate of 0.40 CFM75 per square foot of gross above-grade wall area, tested at 75 Pascals per ASTM E779 or ASTM E1827.
For attached multifamily buildings up to three stories, Section R402.4.1.2 requires individual unit compartmentalization testing at 50 Pa with a maximum of 0.3 CFM50/ft² of unit enclosure area. Sampling is not permitted. Every unit must pass independently.
- Whole-building testing per ASTM E779 / ASTM E1827
- Unit compartmentalization per 2021 IECC § R402.4.1.2
- ASHRAE 90.1 compliance for commercial construction
- Signed engineering report accepted by AHJ
Many states and municipalities have adopted the 2021 IECC or equivalent. We verify the applicable code for your jurisdiction and deliver a report that satisfies your Authority Having Jurisdiction (AHJ).
Why Test an Existing Building?
Air leakage testing is not just a code checkbox for new construction. It is one of the most effective diagnostic tools available for identifying performance problems in existing buildings.
Energy Conservation
Uncontrolled air infiltration accounts for 25–40% of heating and cooling loads in commercial buildings. Whole building blower door testing quantifies the exact leakage rate, giving owners a clear baseline before investing in envelope improvements and measurable proof of savings afterward.
Moisture & Mold
Air movement through the building envelope carries moisture into wall cavities and interstitial spaces. In cold climates this leads to condensation, rot, and mold growth that is often invisible until structural damage has occurred. Pressurization testing locates the breach before it becomes a costly repair.
Indoor Air Quality
Uncontrolled infiltration introduces unconditioned, unfiltered outside air including pollutants, allergens, and vehicle exhaust, directly into occupied spaces. Identifying and sealing major air pathways improves occupant health and reduces the load on mechanical ventilation systems.
Renovation & Re-Commissioning
After a major renovation, addition, or mechanical system upgrade, a post-construction blower door test confirms that the work performed actually improved the envelope. It also supports LEED, ENERGY STAR, and local incentive programs that require verified performance documentation.
Purpose-Built Equipment for Large Volumes
A standard residential blower door produces 2,000–5,000 CFM. A large commercial building may require 50,000–200,000+ CFM to reach the 50 Pascal differential required by ASTM E779. We deploy arrays of 2–20+ calibrated fans synchronized through centralized data acquisition, accurate and code-compliant on facilities of any size.
- Multi-fan arrays up to 20+ units
- Centralized data acquisition across all fans
- Zone-by-zone analysis for phased construction
- Occupied building protocols available
Building Types We Test
Our Testing Process
Site Walk & Test Plan
We walk the building with the project team, reviewing drawings, mechanical systems, and envelope details, then deliver a comprehensive testing plan covering fan array configuration, access points, preparation requirements, and scheduling.
Contract & Building Preparation
Once the scope is agreed upon, we execute a contract and coordinate with the project team to prepare the building for testing. This includes sealing intentional openings including HVAC dampers, exhaust fans, and penetrations, and establishing safe test zones.
Fan Deployment
Deploy and calibrate the fan array across multiple openings, synced to centralized data acquisition.
Pressurization Test
Run pressurization and depressurization sequences, collecting CFM at multiple pressure differentials.
Leak Survey
Systematic envelope survey under pressure, optionally combined with IR thermography.
Report
Engineering report delivered within 5 business days with results, compliance status, and remediation guidance.
What You Receive
Engineering report delivered within 5 business days of on-site testing.
- Pass/fail compliance summary
- CFM50, ACH50, and ELA results
- Code compliance analysis (ASHRAE 90.1, IECC)
- Leak location mapping
- IR thermography images (if selected)
- Prioritized remediation recommendations
- Post-remediation verification available
Testing Standards
Primary protocol for large commercial envelope testing via fan pressurization.
Pulse-technique alternative for shorter tests in occupied or time-sensitive facilities.
Mandates air leakage thresholds for new commercial construction and major renovations.
International Energy Conservation Code and local variants for new construction compliance.
Requires individual unit compartmentalization testing for attached multifamily dwellings, max 0.3 CFM50/ft² at 50 Pa.
Multifamily Unit Compartmentalization Testing
The 2021 IECC requires each dwelling unit in attached multifamily buildings to be tested and pass independently. Sampling is not permitted. This applies to attached dwellings up to three stories under the residential provisions.
Unit Enclosure Area
Leakage is measured against the combined surface area of all six bounding surfaces, including floors, ceilings, exterior walls, and party walls shared with adjacent units, corridors, or stairwells. This surface-area metric is better suited to multifamily geometry than ACH50, which penalizes units with little exterior exposure.
How the Test Works
- Blower door installed in the unit entry door
- Unit windows and exterior doors remain closed
- Adjacent unit doors and windows opened to outside
- Unit depressurized to 50 Pa; CFM50 divided by enclosure area
- Each unit passes or fails independently
Common Questions
Can you perform unit compartmentalization testing for multifamily buildings?
Yes. The 2021 IECC (Section R402.4.1.2) requires each dwelling unit in attached multifamily buildings up to three stories to pass an individual compartmentalization test at 50 Pa. The limit is 0.3 CFM50 per square foot of unit enclosure area, including all floors, ceilings, and walls surrounding the unit. We test each unit individually and deliver per-unit results for code compliance.
How long does testing take?
Large buildings (200,000–1,000,000 sq ft) typically require 1–3 days on-site including setup, testing, and leak survey. We schedule around your operations.
Can you test occupied buildings?
Yes. We use the ASTM E1827 pulse technique with carefully managed pressurization protocols suited to partially or fully occupied facilities.
How is this different from a residential blower door test?
A residential test uses one fan producing 2,000–5,000 CFM. A large building may require 50,000–200,000+ CFM to reach 50 Pa. We deploy arrays of 2–20+ calibrated fans with centralized data acquisition built for large volumes.
Ready to Schedule Your Test?
Share your building size and location and we'll put together a scope and estimate within one business day.
Request a Quote