The Earthquake-prone building (EPB) system for managing earthquake-prone buildings targets buildings and parts of buildings that pose the greatest risk to public safety or other property in a moderate earthquake event.
The EPB system provides consistency for the way buildings are managed for future earthquakes is consistent and strikes a balance between the following:
The diagram below shows the factors that are taken into account.
Territorial authorities, engineers and building owners have key roles to play under the system for managing earthquake-prone buildings.
These are set out in the Building Act 2004 and can be summarised as:
The Building Act also divides Aotearoa/New Zealand into three seismic risk areas – high, medium and low.
There are set time frames, based on these seismic risk areas. They include time frames for territorial authorities to identify potentially earthquake-prone buildings and for building owners to remediate earthquake-prone buildings.
There is also a category of ‘priority buildings’ in high and medium seismic risk areas. These are buildings that are considered higher risk because of their construction, type, use or location. They must be identified and remediated in half the time allowed for other buildings in the area.
The system will also ensure information about earthquake-prone buildings is publicly-accessible through the EPB register.
For more information on the steps in the process of identifying, assessing and making decisions on earthquake-prone buildings you can read:
The core legal documents and tools that support the system are described below.
The Building Act 2004 is available on the Legislation website.
Building (Infringement Offences, Fees, and Forms) Regulations 2007 on the Legislation website has information about fees and offences.
The system focuses on the most vulnerable buildings, in terms of public safety.
The earthquake-prone building provisions apply to non-residential buildings and some larger residential buildings – those that are at least two storeys and either:
Some buildings are specifically excluded, including farm buildings, retaining walls, fences, certain monuments, wharves, bridges, tunnels and storage tanks.
Farm buildings are specifically excluded because of the expected low consequence of failure of these types of buildings.
Farm buildings are those buildings, on farms, that are primarily used for farming activities or an ancillary purpose. Examples of the types of buildings that can be considered as farm buildings are stables, wool sheds, cow sheds, hay barns, herd homes, implement sheds, milking sheds, fattening units, ancillary buildings and storage buildings.
Buildings on farms that are not related to farming activities should not be considered as farm buildings.
Buildings on farms that are more akin to industrial or manufacturing type facilities should not be considered as farm buildings, for example, manufacturing plants, packhouses, and vineyards. However, as these facilities are generally modern buildings, they are unlikely to be earthquake-prone.
A whole building or a part of a building can be earthquake prone.
This means that engineers assessing potentially earthquake-prone buildings need to consider vulnerable parts of buildings, such as unreinforced masonry parapets, as well as the overall performance of the whole building.
A part is an individual building element – such as a unreinforced masonry parapet – which would pose a life safety hazard if it fell or caused another building element to fall during a moderate earthquake.
The methodology to identify earthquake-prone buildings sets out how engineers are required to consider and report on parts of buildings when undertaking an engineering assessment.
The system categorises New Zealand into three seismic risk areas – high, medium and low. These are defined using the 'Z' factor, which is the seismic hazard factor for each area of New Zealand. The Z factor is used when designing new buildings to comply with the Building Code.
These seismic risk areas are used to set time frames for identifying and remediating earthquake-prone buildings.
Territorial authorities have set time frames to identify potentially earthquake-prone buildings using the profile categories in the EPB methodology.
Owners of earthquake-prone buildings are required to take action to remediate their buildings within time frames depending on the seismic risk area their building is located in.
| Seismic risk area | Z factor | Example locations |
|---|---|---|
| High | Z ≥ 0.3 | Gisborne, Napier, Hastings, Palmerston North, Wellington, Blenheim, Christchurch |
| Medium | 0.15 ≤ Z < 0.3 | Tauranga, Hamilton, Rotorua, New Plymouth, Whanganui, Nelson, Timaru, Invercargill |
| Low | Z < 0.15 | Northland, Auckland, Oamaru, Dunedin |
Z-values to determine seismic risk specifies the Z factor for each location.
| Seismic risk area | TAs must identify potentially earthquake-prone buildings by: | Owners of earthquake-prone buildings must carry out seismic work within (time from issue of EPB notice): | ||
|---|---|---|---|---|
| Priority | Other | Priority | Other | |
| High | 1 Jan 2020 | 1 July 2022 | 7.5 years | 15 years |
| Medium | 1 July 2022 | 1 July 2027 | 12.5 years | 25 years |
| Low | N/A | 1 July 2032 | N/A | 35 years |
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The Building Act 2004 requires all territorial authorities (TAs) to report regularly to MBIE on their progress in identifying potential earthquake-prone buildings (EPBs). The following reports show the progress made each year by TAs depending on their reporting cycle.
Priority buildings are certain types of earthquake-prone buildings in high and medium seismic risk areas that are considered to present a higher risk because of their construction type, use or location.
Overview of priority buildings.
Priority buildings need to be identified and remediated within half the time available for other buildings in the same seismic risk areas.
There are two key categories of priority buildings:
The Building Act 2004 on the Legislation website has more information on priority buildings.
Information about earthquake-prone buildings will be publicly displayed on the buildings themselves and available in an online register.
EPB notices must be placed on all buildings that are determined to be earthquake prone. These notices contain the building’s earthquake rating (where available) and the deadline for it to be remediated.
The information must also be entered in a public register of earthquake-prone buildings which is maintained by MBIE. Information is entered by territorial authorities and will build up progressively as territorial authorities determine which buildings are earthquake prone.
