Whole Building Air Leakage Testing Is Changing Energy Code Requirements
Energy codes for metal buildings undergo periodic updates, with these codes setting the mandatory minimum standards to which designers, builders and contractors must comply when fabricating and erecting metal buildings. The most current and widely used documents that set energy efficiency and energy code guidelines for metal buildings are ASHRAE 90.1-2019 and IECC 2021.
Among the more notable changes made to these documents include new requirements for air leakage testing for metal buildings. Before, these requirements, which seek to improve the performance of a building’s thermal envelope, were only in place in a few states. Prior editions of ASHRAE 90.1-2019 and IECC 2021 left them optional in most other areas.
Testing for and Reducing Air Leakage
Metal buildings, in general, are resistant to air leakage. Many pass air leakage tests with relative ease. Most air leakage tests involve the use of certain diagnostic tools, such as synthetic smoke, to identify where leaks exist, and they usually take about a day to complete.
There are certain areas within a steel building that may be more prone to air leakage than others. Doors and windows are common sources of air leaks. Seams and gaps along the building envelope may also allow air to escape, particularly if proper care isn’t taken during erection.
Insulating metal buildings is a highly effective way to reduce air leakage. However, extra care is necessary when installing the insulation, as gaps or tears in the insulation system also have the potential to let air escape.
Air Leak Testing Process
*Photos Provided by Courtesy of MBMA
ASHRAE 90.1-2019 Exceptions
ASHRAE 90.1-2019 requires most buildings to undergo whole building air leakage tests with just a handful of exceptions. The only buildings exempt from air leakage testing under ASHRAE 90.1-2019 include semi-heated buildings in Climate Zones 1 – 6. However, buildings may be able to comply with the terms of ASHRAE 90.1-2019 by going through an installation verification program instead of undergoing whole building air leakage testing.
IECC 2021 Exceptions
IECC 2021 also requires most buildings to undergo whole building air leakage tests, but again, there are a few exceptions. Buildings constructed within Climate Zones 2B, 3B, 3C and 5C are exempt. So, too, are buildings in Climate Zones 1, 2A, 4B and 4C that span more than 5,000 square feet, and buildings in Climate Zones 3A and 5B that fall between 5,000 and 50,000 square feet. Unlike with ASHRAE 90.1-2019, there is no way other than air leakage testing for buildings that are not exempt to meet the terms of IECC 2021.
If you are interested in learning more about Metal Building Energy Codes and Construction, the Metal Building Contractors & Erectors Association (MBCEA) provides training courses and information on the most current construction techniques and requirements.
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