WA State: HB 1458 Embodied Carbon and building materials (Proposed)
House Bill 1458 focuses on reducing the embodied carbon emissions associated with buildings and building materials in Washington state. Embodied carbon refers to the greenhouse gas emissions released during the lifecycle of building materials, from raw material extraction and manufacturing to transportation and installation.
The bill directs the State Building Code Council (SBCC) to adopt rules establishing embodied carbon emission reduction standards for building projects. These standards will apply to new construction, additions, and renovations of 50,000 square feet or larger. The SBCC is instructed to consult with various state agencies and other stakeholders in developing these rules. An existing technical advisory group will provide recommendations to the SBCC regarding modifications to the International Building Code related to these standards.
The bill outlines three distinct pathways for building projects to comply with the new embodied carbon emission reduction standards. The first path involves Existing Building Reuse, where projects that preserve at least 45% of an existing structure and its envelope are considered compliant. Additions to these reused buildings are limited to 50% of the original area. The SBCC will define how this 45% reuse is calculated.
The second path, Covered Products, allows projects to meet the standards by demonstrating that the embodied carbon emissions of the building materials used meet specified reduction targets. This reduction is measured by comparing the global warming potential of the project's materials to industry averages. The project's design professional is responsible for calculating and verifying these emissions based on environmental product declarations (EPDs) from the manufacturers.
The third option, Whole Building Life-Cycle Assessment (WBLCA), allows projects to demonstrate reductions by comparing the building's projected lifecycle emissions to a functionally equivalent reference building. This assessment considers the environmental impact of the building over its entire lifespan. The design professional must attest to the accuracy of the WBLCA and submit it with the building permit.
The bill also mandates the creation of a standard reporting form and a public database by the Department of Commerce. This database will track embodied carbon emissions data from building projects, including basic project information, the chosen compliance pathway, and how the project met the selected pathway’s standards. Commerce will also create a public website with educational resources and a list of compliant software programs. Additionally, Commerce will conduct annual audits of 3% of reported projects.
A key provision of the bill requires that construction permitted under the 2030 State Building Code achieve a 30% reduction in embodied carbon emissions compared to a project-wide static baseline. This requirement excludes projects complying through the Existing Building Reuse pathway. The SBCC will progressively incorporate requirements into the 2027 and 2030 code cycles to reach this target. The SBCC and Commerce will provide regular progress reports.
The House Committee on Local Government passed a substitute bill, with the majority recommending passage and the minority opposing. Public testimony revealed support for the bill's goals, with proponents highlighting the feasibility of the proposed pathways and the importance of addressing embodied carbon to meet emission reduction targets. Concerns were raised about the scalability of certain materials, the placement of embodied carbon regulations within the building code, and potential cost increases.