The release of the updated National Seismic Hazard Model in 2022 has prompted the drafting of a revised NZ Standard for seismic loading of new buildings, currently referred to as a Technical Specification (1170.5). This draft has recently wrapped up its public consultation phase and will soon undergo further revision.
The eventual adoption of this Technical Specification as a formal NZ Standard will influence the NBS (National Building Standard) rating of all buildings. As new buildings are required to meet higher seismic performance standards, the standards for existing buildings will also need be elevated to maintain parity.
Why does this mean for building owners and tenants? This shift will ultimately lead to changes in how earthquake resilience is assessed for existing buildings, resulting in more disputes regarding a building’s rating, and rising frustration for landlords who may have recently carried strengthening works.
A brief historical overview
In the early 2000s, seismic ratings were largely overlooked unless a building was suspected to be earthquake-prone. By 2006 however, the NZ Society for Earthquake Engineering (NZEE) in conjunction with the Ministry of Housing had developed guidelines for assessing whether an existing building was earthquake-prone. At that time, the property industry had relatively limited experience with these assessments, and they were not heavily considered in tenant evaluations of new space.
However between 2010 and 2018, research from the 2010 and 2016 earthquakes led to new guidelines drafted by NZSEE, the Ministry of Business Innovation and Employment (MBIE), and the engineering sector. This culminated in the 2017 ‘Red Book’. These guidelines marked a significant shift in:
- Legislation: The guidelines became the foundation for new legislation introduced in 2016, establishing the earthquake prone building (EPB) regime, setting timelines for upgrading EPB’s and creating penalties for failing to do so.
- Standards for resilience: The property industry now had a clear benchmark for assessing resilience. Tenants were better able to compare resilience across buildings, and landlords could more accurately gauge the necessary improvements required to attract and retain tenants.
Challenges and changes
In late 2018, a revision known as the “Yellow Chapter” updated the guidelines, specifically for assessing concrete buildings with pre-cast floors. Although MBIE clarified the revision has not been legislated (the Red Book remains the standard for determining earthquake-prone buildings), the industry could not ignore the updated guidelines.
The Yellow Chapter has created division. Property owners have emphasized the Red Book for compliance, while tenants have adopted the Yellow Chapter as their benchmark for resilience. This has led in many cases to substantial structural costs for landlords in order to meet tenant expectations.
Further complicating the situation, a new revision of the guidelines is currently under consultation. This revision proposes updated procedures for assessing pre-cast floors, which may require even more structural reinforcement to maintain existing ratings.
Further change
Adding to the uncertainty, the Government has announced a review of the earthquake-prone building regime, with Terms of Reference recently released. The review will consider whether the current NBS regime remains effective or if a new approach should be adopted. This review is expected to be presented to Cabinet in Q2 2025.
While advancements in engineering and construction are crucial for improving building design and safety, they pose challenges for existing structures needing adaptation to stay competitive. The rapid pace of new learning creates a double-edged sword for landlords and tenants, as the industry struggles to keep up with constant changes.
In this evolving landscape, both landlords and tenants must stay informed and agile to adapt to the constantly changing seismic standards. Navigating these complexities requires more than just technical expertise, but also a balanced commercial perspective that considers both risk management and long-term investment.
The path forward may be challenging, but proactive engagement will ultimately support resilience in these changing times.
