Principles to help agencies follow legislation and meet their obligations related to seismic safety.
Seismic assessments are an important part of managing the government office accommodation portfolio. We help agencies understand their seismic risk ratings and building vulnerabilities. This guidance needs to be taken into consideration alongside the Building Performance team's Seismic Risk Guidance for Buildings document.
The following principles provide guidance for agency spaces that are part of the Government Property Group (GPG) mandate, and are not intended to guide your decisions around operational spaces like prisons, hospitals and schools. This guidance does not supersede or replace the Building Performance team's seismic advice or create a separate standard for government tenants.
Seismic Risk Guidance for Buildings [PDF 2.7 MB] – Building Performance
Committing your agency to a lease means doing your due diligence and having all necessary information early in the leasing process. You should understand the benefits and risks of occupying a building, including its seismic resilience, before you decide to lease it or renew an existing lease.
There are two forms of building seismic assessments in New Zealand:
For a detailed assessment, engineers assess the vulnerability of all critical elements in the building that could become a significant safety hazard during an earthquake, for example, columns, floors, parapets, heavy exterior cladding. Each element receives a percentage score rating it against the New Building Standard, and the element with the worst performance represents the overall earthquake rating for the building (%NBS).
Seismic assessments usually only consider primary and secondary elements of the building structure, and exclude the seismic performance of services (plumbing, electrical, communications, HVAC), internal fit-outs or office equipment. You may need to separately engage an engineer to assess the performance of these elements.
When committing to a long lease for a building not currently within the Government Property Portfolio, a DSA is recommended to ensure the seismic rating is well understood. Getting a DSA can take time, but some landlords will already have one available. Be aware that a DSA is complex, and may require peer review by an engineer.
Even if the landlord already has an ISA or DSA for their building that you can review, you should still consult with an independent engineer to make sure the assessment is appropriate. A seismic assessment gained before 2017 may help identify potential vulnerabilities but these often don't include assessment of critical components, such as precast floors.
We keep a central record of the seismic ratings of buildings to help agencies identify suitable buildings for long term occupation, and to support our work enhancing the quality and resilience of government property.
You should understand and report any potential vulnerabilities of the buildings which your agency occupies or intends to occupy, including the seismic risk rating.
Make sure to record the following information in the Government Property Portal:
Decisions on whether an agency remains in a co-location as the result of a seismic rating need to be made by all occupying agencies. This ensures a consistent approach and takes into consideration a chief executive’s responsibility as a person conducting a business or undertaking (PCBU), as outlined by WorkSafe.
While individual agency chief executives are responsible for their staff when deciding to continue to occupy a building, they may arrive at different decisions. We’re here to help agencies work through the process.
If a building is less than 34% of the New Building Standard, it may be classified as earthquake-prone under the Building (Earthquake-prone buildings) Amendment Act 2016 (EPB). This means the building is more likely to sustain damage in a moderate earthquake and, as a result, there is a higher risk than in a new building. The law requires that this risk reduces over time.
If a building is greater than or equal to 34% NBS, but less than 100% NBS, the building is determined to pose a somewhat higher risk than a new building.
When you lease a building, particularly for long term leases, you should encourage your landlord to improve the seismic resilience of your building, particularly if the building is in the 34 to 66% NBS range. A low NBS rating isn't necessarily cause for alarm, unless the building element of concern indicates a safety risk.
>The diagram shows a colour graded box (blue to amber) indicating the gradual reduction in life safety risk as the %NBS rating increases. The box is divided into thirds vertically, showing risk, approximate %NBS range and recommended mitigation measures for each third.
Understanding the vulnerability of different building elements, and the potential consequences, is more important than the overall NBS rating. Your engineer can help when it comes to making any mitigation and occupancy decisions.
Government agencies accounting for seismic concerns should use the Seismic Risk Guidance for Buildings document, along with this guidance. For example, when an agency is considering the occupation of a building not currently within their portfolio, preference should be given to existing buildings achieving a minimum rating of grade B (67 to 79% NBS).
Consider incorporating elements of low damage design in new buildings to assist with resilience planning. Low damage design seeks to minimise repairs and downtime after an earthquake, while still meeting the life safety requirements of the Building Code.
You should apply a consistent approach and understand a building’s vulnerabilities when making decisions that will affect the lease commitments of the government’s asset portfolio. The terms of government leases are often lengthy, and the Government Property Group team can help agencies understand government expectations when entering a new lease or renewal.
There are many variables involved in seismic assessments, which can lead to some uncertainty when calculating risk. This means that NBS can be seen as an indicator of the engineer’s confidence in the expected seismic performance of the building, not an exact prediction. Buildings also perform differently depending on the type of earthquake, so a one-size-fits-all approach isn't possible.
If you receive an initial seismic assessment (ISA) identifying areas of concern, encourage the building owner to undertake a detailed seismic assessment (DSA). If the landlord isn’t prepared to do a DSA, you should consider getting one yourself. You will need the landlord’s cooperation as the engineers will need the building designs and other key materials to assist with their modelling. It's also worth discussing the potential to share costs with the landlord.
A DSA should be peer reviewed by an independent chartered engineer.
We recommend that occupancy decisions are not made until you receive a DSA, unless your engineering advice states your building isn't safe. You should discuss the DSA with your engineer, GPG and other key stakeholders.
Decisions to vacate or continue to occupy a building have legal and financial implications for your lease. In some cases, continued occupation requires negotiating with the landlord to undertake remediation works, particularly where seismic rating expectations aren't incorporated into your current lease terms.
When there is significant disagreement over a seismic report, Engineering New Zealand offers independent facilitation so that engineers can agree on a narrower assessment rating.
Reconciling differing seismic assessments – Te Ao Rangahau Engineering New Zealand
All buildings should be assessed for seismic risk at various points in a property’s lifecycle. This can be done when concerns are identified, a lease is coming up for renewal or an agency is considering moving to new premises.
There are seven key factors to consider when deciding whether a building is safe to occupy. Each contains a different risk rating depending on the circumstances, and should be considered in the context of the overall rating. The Seismic Risk Guidance for Buildings document has specific information on each of these factors and we can help you work through options. The factors are:
Ultimately, it is the responsibility of a person conducting a business or undertaking (PCBU) to decide how suitable a particular building is for occupancy. WorkSafe has information available on the responsibilities of a PCBU.
Who or what is a PCBU? – Mahi Haumaru Aotearoa WorkSafe
Agencies need to understand the seismic profile of a building before entering a lease. Our new lease template contains seismic provisions. It also sets out expectations for ongoing seismic performance and warranties. We can help you ensure the appropriate clauses are included to acknowledge the government as a long-term tenant.
If you are renewing a lease, you should incorporate these seismic provisions, particularly for longer lease terms. Email the Government Property Group team for the latest lease template.