ASHRAE Journal - June 2024 - 32

FEATURE
Standard 228 can be used during the design and
operation phases of new and existing buildings to
track energy and carbon performance during their
lifetime to verify whether the annual net energy use
and the carbon emissions are zero. In practice, weather
extremes, building occupancy and the state of the
building can have significant impacts on energy and
carbon use. Without sufficient ongoing maintenance or
ongoing commissioning, a building can go out of tune
significantly in only a handful of years; therefore, one of
the best use cases of the standard is continual tracking,
where it can inform adjustments made to the building
operation and systems as needed to maintain zero net
energy or zero net carbon operation.
Standard 228's first major application was
demonstrated in a U.S. Department of Energy request
for information issued in December 2023 to propose
a " National Definition of a Zero Emissions Building. "
The first discussion draft of the definition cited
Sections 8.3-8.5 of Standard 228 as one of three paths
to qualify off-site renewable energy for use in a zero
emissions building.
The standard provides a standardized approach of
evaluating zero net energy or zero carbon operations
of a building or group of buildings. These statuses are
achieved by demonstrating that the energy flows or
associated carbon emissions coming into a site are
less than or equal to those flowing outward during
building/site operation and need to be updated each
year to determine and report energy and carbon values
and maintain status.
Standard 228 aligns with ANSI/ASHRAE Standard 105,
Standard Methods of Determining, Expressing, and Comparing
Building Energy Performance and Greenhouse Gas Emissions, in
regard to energy and carbon flows across a site boundary
and their measurement and balance. Additionally,
Standard 228 includes allowances for sites that cannot
produce sufficient clean energy on site.
Generally, two options exist for energy calculations:
site and source. Site energy is the energy consumption
of the building similar to what is measured by utility
meters, while source energy also includes energy used
to extract and process fuels and losses during energy
distribution. Standard 228 incorporates source energy
to give a more complete energy and carbon assessment.
The default energy calculation method relies on
annual average factors, but qualified professionals can
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ASHRAE JOURNAL ashrae.org J U N E 2024
aggregate actual energy (and carbon) data to be used in
place of the default factors.
Originally, the scope of Standard 228 was limited to
energy but was expanded to include carbon, aligning
with ASHRAE's decarbonization impact goals and its
leadership role in combating climate change through
reducing carbon emissions of the built environment.
This expanded scope supports ASHRAE's commitment
to " Develop technical guidance, standards, training and
other tools to support building decarbonization policy
goals " and to continue its lead " in building design,
operations and technology for more than a century, "
per the " ASHRAE Position Document on Building
Decarbonization. " To incorporate carbon, Standard 228
uses carbon dioxide equivalent (CO2e) to normalize
and account for the greenhouse warming effects of
different emission gases involved in site or source
energy integrated over the 100 year period after their
release. Leakage of refrigerants from building systems is
also included because of its potential to be a substantial
contributor to an operational carbon footprint.
Who Created Standard 228-2023 and How Was It Written?
The standard was created by a committee of ASHRAE
members who represented future standard users,
producers of products that would be affected by the
standard, members involved with compliance by
authorities having jurisdiction and ASHRAE members
with a general interest in the standard. In general,
the authors were ASHRAE members who are widely
recognized for their experience and contributions to the
fields of building energy efficiency and decarbonization.
What is Contained in Standard 228-2023?
Compliance
Buildings, portions of buildings, portfolios and
communities in any phase of their life cycle can qualify
to be considered " zero net energy " or " zero net carbon "
under Standard 228 if they meet the appropriate
compliance requirements. Four categories of buildings
or groups of buildings have been defined:
y Proposed zero net energy and zero net carbon
buildings and their sites-buildings or portions in
design or construction;
y New zero net energy and zero net carbon buildings
and their sites-buildings or portions that have been
occupied in their most recent occupancy class for less
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ASHRAE Journal - June 2024

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