Building Enclosure Airtightness
Testing In Washington State
LESSONS LEARNED ABOUT AIR BARRIER SYSTEMS
AND LARGE BUILDING TESTING PROCEDURES
JULY 1, 2014
PRESENTED BY DENALI JONES, RDH BUILDING SCIENCES, SEATTLE
ASHRAE 2014 Annual Conference
Seattle WA
Overview
Airtightness Testing
What is it?
Why test?
2009 vs. 2012 energy codes
Testing Procedures
ASTM E779 and USACE
Single-family vs. large building
Challenges with large tests
Test Results & Discussion
Different air barrier types
Common leakage areas
Summary & Conclusion
What is an Air Barrier?
A system of materials and components that resist the
flow of air under a given air pressure difference
Code requirements:
Continuous
Components are joined and sealed in a flexible manner,
allowing for relative movement
Withstands combined forces (negative and positive)
without displacing adjacent materials
Materials: 0.004 cfm/ft2 @ 75Pa
Assemblies: 0.04 cfm/ft2 @ 75Pa
Whole building: 0.4 cfm/ft2 @ 75Pa
Primary Air Barrier Systems
Sealed Sheathing Sheet-Applied Liquid-Applied
Self-AdheredCurtain Wall/Window
Wall/Storefront
Forces On Air Barriers
Stack Effect
Wind
Mechanical Systems
Quantitative testing of air barrier
system performance
Calibrated fans pressurize the
building and measure flow
Flow in = flow out
Results in cfm/ft2
of surface area
Whole-Building Airtightness Testing – What is it?
Simple answer: because the
code says you have to.
To confirm air barrier
performance
To identify air leakage
pathways
To establish a number for
future comparison
Whole-Building Airtightness Testing – Why Test?
2009 Energy Codes
2009 Seattle Energy Code (SEC)
All nonresidential and multifamily family residential
buildings must be tested.
Required* to achieve 0.4 cfm/ft2
2009 Washington State Energy Code (WSEC)
All nonresidential buildings > 5 stories must be
tested.
Required* to achieve 0.4 cfm/ft2
*Requirement waived if air barrier has been inspected by a third party.
Nonresidential air leakage testing requirements:
2012 Energy Codes
All nonresidential buildings must be tested.
All buildings > 3 stories must be tested.
Required* to achieve 0.4 cfm/ft2
or better.
*If 0.4 is not achieved, then reasonable efforts must be made to seal all
leaks and an additional report must be submitted to the code official.
WSEC and SEC nonresidential air leakage testing
requirements:
Testing Procedures – ASTM E 779 & USACE
Measure flow at multiple pressures (multipoint testing).
Test Procedures – Large Building Challenges
The concept is simple… but the execution…
Test Results - How airtight are these buildings?
Tested 31 buildings
All under 2009 code cycle
Air barrier type refers to walls
Test Results – How airtight are these buildings?
Takeaways - What it takes to get an airtight building
The Good
Repetitive, simple details
Few trade interfaces
Experienced design team,
general contractor, and trades
Coordination of design team,
contractor, and trades
Takeaways – What it takes to get an airtight building
The Bad
Owner/Contractor doesn’t
perceive value in
airtightness
Poor/incomplete detailing
Inexperienced trades
Difficult review conditions
What’s Next?
Code target of 0.4 cfm/ft2
is attainable.
Better coordination between HVAC and envelope
designers = better performance.
We know how airtight buildings are; size mechanical
ventilation accordingly.
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Discussion + Questions
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