Standards Support Decarbonization in Building Design and Operations

With I2SL is focused on helping decarbonize laboratories, we can also look to other organizations and agencies supporting the broader goal of decarbonization across the built environment by clearly defining terms such as “net zero” and setting consensus-based standards calculating them. The following examples help lay the groundwork for consistency among architecture, engineering, construction, and consulting groups supporting lab buildings’ efforts to improve energy efficiency performance and emissions reduction.

National Definition of Zero Emissions Building. In June, U.S. Department of Energy released a definition for zero emissions building: a building that is highly energy-efficient, does not emit greenhouse gases (GHGs) directly from energy use, and is powered solely by clean energy (which means that all the building’s energy is from carbon-free sources, including onsite renewable generation and off-site sources). The definition is part of a larger, national Blueprint for the Buildings Sector to reduce U.S. building emissions 65 percent by 2035 and 90 percent by 2050. It can be applied to existing buildings or new construction, in both the commercial and residential sectors.

ANSI/ASHRAE Standard 228: Standard Method of Evaluating Zero Net Energy and Zero Net Carbon Building Performance. Published in spring 2023, this draws from other ASHRAE standards and sets parameters for quantifying energy flows and associated carbon emissions in order to evaluate building performance at a point in time and over multiple years. Standard 228-2023 covers whole buildings or sections that are in design/under construction; new construction recently completed/occupied; existing buildings; and entire portfolios or communities of buildings. Each energy flow to the building or section is quantified and converted to consistent units, and an energy balance equation determines whether it qualifies as “zero net energy”; the equation also takes emissions factors into account to determine whether it is “zero net carbon.” Source energy is used in the zero net energy calculation, and site energy use is multiplied by GHG emissions factors provided in the standard to determine zero net carbon status. Off-site renewable energy purchases may be used in most cases to comply, but renewable energy certificates must be retired.

Because the energy and emissions balance approach provides a clear picture on where emissions are coming from, those who use the standard can identify measures that can help reduce the carbon footprint of an existing lab building (or one in design). In the future, working with the tools provided by I2SL’s Lab Benchmarking Tool and Labs2Zero program, this new standard can help our members improve the energy and emissions performance of buildings now and labs in the future.

ASHRAE Standard 240P: Quantification of Lifecycle Greenhouse Gas Emissions. For evaluating the emissions associated with a building—whether operational or embodied—this proposed standard provides minimum requirements for quantifying them over the life cycle of the building, as well as the minimum documentation required. The standard would set the criteria for what to include in the material inventory for embodied carbon. The standard defines embodied carbon as the GHG emissions associated with extraction, production, transportation, and construction, as well as deconstruction and end-of-life disposition of construction materials, and the boundary of lifecycle stages covered. I2SL’s embodied carbon benchmarking approach is consistent with this standard.

For operational emissions, the boundary includes operational energy, water, and exported energy. The standard provides general data requirements, GHG emissions factors, quantification methods, and data requirements for fugitive emissions. Water, however, need only be included if the jurisdiction requires it.  The standard also provides guidance for as-designed and as-built data.