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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