Cost-Benefit Analysis for a Building Code Change

Abstract

This document proposes a cost-benefit analysis (CBA) method to assess a building code change for engineered buildings in Aotearoa New Zealand. The proposed methodology is based on the methodology used in the Natural Hazard Mitigation Saves 2019 Report (henceforth the NIBS report) by the United States’ National Institute of Building Sciences (NIBS, 2019). New Zealand has recently completed its 2022 National Seismic Hazard Model (NSHM), and it suggests that it “will be used to inform regulations related to meeting Building Code requirements and for loss modelling needs in New Zealand.” (Gerstenberger et al., 2022, p. 1). It seems inevitable that these building code requirements will be strengthened as the report finds “in general, over most of New Zealand and for most hazard metrics, the NSHM 2022 forecasts increased hazard when compared to the 2010 NSHM.” (Gerstenberger et al., 2022, p. 101). This impending tightening of the building code is the impetus for this report’s consideration of an up-to-date CBA assessment methodology for this type of policy change.