Seismic Work Programme

Last updated: 4 July 2022

As stewards of the building regulatory system, MBIE has established the Seismic Work Programme to ensure we adapt to new knowledge around building performance.

Programme background

The Building Performance team in the Ministry of Business, Innovation, and Employment (MBIE) is responsible for managing New Zealand's central regulatory system for building. This includes being responsible for and implementing changes to building legislation and regulations to meet New Zealand’s current and future needs.

One objective of the Seismic Work Programme is to manage seismic risk to existing buildings. This involves using the latest results from the National Seismic Hazard Model (NSHM), which is being updated by GNS Science, Te Pū Ao.

The programme will consider how the NSHM results should be used within the building code to support the design and construction of future buildings. There is also a focus on managing the seismic risk of existing buildings.

Seismic risk guidance

Engineering design standards and our understanding of earthquakes have advanced over time, in particular as a result of learnings from the 2011 Canterbury and 2016 Kaikōura earthquakes. Consequently, many older buildings do not meet the standards required of new buildings.

In light of this, MBIE is releasing this new guidance to help building users, tenants and owners understand seismic assessments of their buildings and make risk-informed decisions about continued occupancy of these buildings when they have a low seismic rating.

The guidance also provides the tools and language for engineers and their clients to discuss seismic assessments and what these mean for building performance in an earthquake.

The guidance is in three parts:

  • Part A: Obtaining and understanding Seismic Assessments
  • Part B: Process for making occupancy decisions
  • Part C: Managing ongoing earthquake risk and communicating with staff.

Understanding percentage of New Building Standard

The percentage of New Building Standard (%NBS) is an index used to characterise the expected seismic response of a building to earthquake shaking. It identifies buildings that represent a higher seismic risk than a similar new building, built to the minimum life safety requirements of the Building Code (or New Building Standard).

The aim of the %NBS metric is to provide a relative assessment of seismic risk. It is not a predictor of building failure in any particular earthquake. In most cases, seismically vulnerable buildings can be occupied while you plan, fund and then undertake seismic remediation work.

The %NBS metric was specifically developed to support the implementation of the earthquake-prone building legislation. The legislation seeks to quantify the seismic performance of buildings in relation to an equivalent new building, and a simple metric was needed to classify buildings. %NBS building ratings were not intended to be used to support building occupancy decisions.

Making decisions about seismic assessments

The purpose of seismic assessments is to inform building owners and users about their building vulnerabilities, encourage strengthening of vulnerable buildings and lead to the improvement of our building stock over a reasonable time period. When the outcome of a seismic assessment is a low %NBS rating, this should be a trigger for planning, funding and implementing a seismic upgrade, addressing the identified vulnerabilities and mitigating risk.

It is recommended that occupancy decisions should not be made until you have received an independently reviewed detailed seismic assessment (DSA) that, if necessary, has been independently reviewed and have had time to discuss and work through Part B of the guidance document with your engineer and other key stakeholders.

The seismic assessment does not change the seismic vulnerability of your building. It is worth taking time to carefully review and understand the DSA so that you can decide how best to manage the risk without creating unintentional harm.

It is very difficult to reverse a building closure decision, so make sure you are confident in the information you have received and decision process you have followed.

It is important to remember that you can never eliminate seismic risk. Even if a building is vacated, staff and building users will be exposed to seismic risk in their homes and other buildings. However, seismic risk can be mitigated through emergency planning and training, as well as restraining plant, services, and contents within the building.

Additional resources

Seismic Risk and Building Regulation in New Zealand – Findings of the Seismic Risk Working Group

This report, developed by a group of experts and MBIE, provides advice on how the updated NSHM could be applied within the Building Code, and outlines the Building Performance teams proposed plan for preparing to update the Building Code.

Rethinking Seismic Risk in the Building Control System – New Zealand Geotechnical Society (nzgs.org)

This information is published by the Ministry of Business, Innovation and Employment’s Chief Executive. It is a general guide only and, if used, does not relieve any person of the obligation to consider any matter to which the information relates according to the circumstances of the particular case. Expert advice may be required in specific circumstances. Where this information relates to assisting people: