California Air Resources Board

Principal Investigator/Author: Arpad Horvath

Contractor: University of California, Berkeley

Contract Number: 21STC018

Project Status: Completed

Relevant CARB Programs: Sustainable Communities & Climate Protection Program

Topic Areas: Climate Change, Research & Sustainable Communities, Sustainable Community Strategies (SCS)

Research Summary:

The goal of this research project is to assess the potential GHG emissions reduction benefits related to the building life cycle, construction materials, and construction processes of two innovative housing methods (adaptive reuse and prefabricated modules) compared to traditional construction methods. The study examines the potential climate benefits of scaling up adaptive reuse and prefabricated construction. The number of buildings that are feasible for repurposing for housing in California is estimated, and the number of potential housing units that could be constructed with prefabricated methods is analyzed. A discussion of potential obstacles and necessary policy-level decisions for supporting adaptive reuse and prefabricated construction in California is conducted.

The research is done scientifically and comprehensively by creating an environmental life-cycle assessment (LCA, according to ISO 14040, 14044, and other ISO standards applicable to buildings) model that will apply to various building types and specific case studies. For each building type analyzed (i.e., a medium office suitable for conversion or a modular housing project), data on the bill of materials and construction activities are collected from actual projects and government and industry databases. GHG emissions from materials, transportation, and construction activities are calculated by relating amounts of materials and fuels consumed in each building project to respective emission factors. The emission factors are cultivated from various sources, including environmental product declarations (EPDs), which are certified industry documents that can often reflect more location and region-specific conditions, models that utilize state-collected data, and additional academic literature sources.

 The research team investigates, by synthesizing experiences from case study projects/developments as gleaned from newspaper sources, whether adaptive reuse and prefabricated construction projects have net positive community benefits as compared to the construction of new housing via traditional construction methods.

Keywords: greenhouse gas (GHG), emissions, construction, housing, buildings, adaptive reuse emissions reductions