Under the Building Act 2004 Council is required to assess the earthquake risk of certain buildings within the district. Buildings that are determined to be earthquake-prone are required to be strengthened or demolished within specific timeframes set by the legislation.
In general, this only applies to non-residential buildings (commercial or industrial) and some larger residential buildings.
The Building (Earthquake-prone Buildings) Amendment Act 2016 introduced major changes to the way earthquake-prone buildings are identified and managed under the Building Act. The system is consistent across the country and focuses on the most vulnerable areas and buildings in terms of people's safety.
Buildings are regarded as earthquake-prone if they are assessed as being less than one-third of the strength required for a new build in the same location in moderate earthquake shaking. This assessment is expressed by a “score” in terms of the percentage of New Building Standard achieved (%NBS). Earthquake-prone buildings have a %NBS of less then, or equal to, 33%NBS.
Managing earthquake-prone buildings
Alongside the change in legislation, a new national system for managing earthquake-prone buildings came into effect on 1 July 2017.
The new system affects owners of earthquake-prone buildings, local councils, engineers, other building professionals and building users.
The new system means:
- local councils must identify potentially earthquake-prone buildings
- owners who are notified by their local council must obtain engineering assessments of the building carried out by a suitably qualified engineer, this will confirm or disprove councils initial identification
- local councils use the engineering assessment to determine whether buildings are earthquake-prone, assign ratings, issue notices and publish information about the buildings in a public register
- owners are required to display notices on their building and to remediate their building.
The Building Act also divides New Zealand into three seismic risk areas – high, medium and low.
An overview of the system including seismic risk areas and time frames can be found on the Ministry of Business, Innovation and Employment (MBIE) “building” website.
What this means for Waikato District
Our district spans across a medium and low seismic risk area, a map of which can be found under related documents at the end of this page. That means our Council has between 5 and 10 years (from 1 July 2017) to identify potentially earthquake-prone buildings within our district.
For information on the methodology used, visit the MBIE website.
Council will inform building owners of a potential earthquake-prone status of their building. Building owners have 12 months to respond to this notice, that is, to confirm or disprove this status.
This will generally require an engineering assessment for their building.
If Council determines that a building is earthquake prone, it needs to:
- assign an earthquake rating for that building,
- issue an earthquake-prone buildings notice to the owner to display prominently on the building, and,
- publish the building information on the earthquake-prone buildings register.
Owners of earthquake-prone buildings who have received a notice must take action within set time frames. The time frames depend on whether the building is a priority building, and the seismic risk area that the building is located in.
Because Waikato district spans across a medium and low seismic risk area, the timeframe to carry out seismic work on buildings identified as an earthquake-prone building between 12.5 and 35 years.
What’s happening now?
We’re currently assessing any buildings categorised as a priority building under the Civil Defence Emergency Management Act 2002 and the Building (Earthquake-prone Buildings) Amendment Act 2016. These priority buildings will be based on their function during an emergency in an earthquake event and could be either a hospital, emergency or education building etc.
The purpose of these assessments is to rule out any potentially earthquake-prone buildings that would be considered as priority in an emergency. Our inspector will be on site to have a walk around these premises, take photos of buildings and provide a report back to us.
These buildings could be used to provide:
- emergency medical services
- used as an emergency shelter or emergency centre
- a building that is used to provide emergency response services (for example policing, fire, ambulance or rescue services)
- a building that is regularly occupied by at least 20 people and that is used as any of the following:
- an early childhood education and care centre licensed under Part 26 of the Education Act 1989
- a registered school or an integrated school (within the meaning of the Education Act 1989)
- a private training establishment registered under Part 18 of the Education Act 1989
- a tertiary institution established under section 162 of the Education Act 1989.
Frequently asked questions
The 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.
Find out more: MBIE Guidance: Managing earthquake-prone buildings
Under the new system for managing earthquake-prone buildings, territorial authorities, engineers and building owners have key roles to play:
- Territorial Authorities identify potentially earthquake-prone buildings.
- Owners who are notified by their territorial authority must get engineering assessments of the building carried out by suitably qualified engineers.
- Territorial Authorities determine whether buildings are earthquake prone, assign ratings, issue notices and publish information about the buildings in a public register.
- Owners are required to display notices on their building and to remediate their building.
There are set timeframes, based on the seismic risk of the area you are in. Our district is located in a medium and low risk zone.
Territorial authorities (local councils) are required to identify potentially earthquake-prone buildings. The EPB methodology sets out how to do this.
Find out more about the methodology please visit: Identifying potentially earthquake-prone buildings
Territorial authorities determine whether or not a building or part of a building is earthquake-prone. They normally make this decision after the building has been identified as potentially earthquake-prone and assessed by an engineer.
The following profile categories are used to identify potentially earthquake-prone buildings:
| Category | Description |
|---|
| Category A | Unreinforced masonry buildings |
| Category B | Pre-1976 buildings that are either three or more storeys or 12m or greater in height above the lowest ground level (other than unreinforced masonry buildings in Category A) Pre-1976 buildings that are either three or more storeys or 12m or greater in height above the lowest ground level (other than unreinforced masonry buildings in Category A) |
| Category C | Pre-1935 buildings that are one or two storeys (other than unreinforced masonry buildings in Category A) |
A key criteria for determining whether a building is earthquake prone is whether the building, or any element of it scores less than 34% when assessed against the National Building Standard (NBS).
Find out more:
Information Sheet: Deciding if a building is earthquake prone
Guidance: The methodology to identify earthquake-prone buildings
Priority buildings are certain types of buildings in high and medium seismic risk areas that are considered to present a higher risk because of their construction, type, use or location. They may be buildings that are considered to pose a higher risk to life safety or buildings that are critical to recovery in an emergency.
Priority buildings need to be identified and remediated within half the time allowed for other buildings in the same seismic risk areas.
Find out more: Guidance for Priority Building
When a territorial authority identifies a building as potentially earthquake prone, the building owner is required to provide an engineering assessment for their building within 12 months from the date they are notified. The building owner can apply for one extension of up to 12 months in certain circumstances.
Find out more: Assessing potentially earthquake-prone buildings
Owners of earthquake-prone buildings who have received an EPB notice must take action within set time frames. The time frames depend on whether the building is a priority building.
Owners can either strengthen their building so it is no longer earthquake-prone, or demolish it to remove the risk within the timeframe specified on the EPB notice. A structural engineer can provide advice on an approach that is suitable for the building.
Owners of certain heritage buildings that are determined to be earthquake-prone can apply to their territorial authority for more time – up to 10 years longer – to strengthen their buildings.
Owners of some earthquake-prone buildings may be eligible to apply for an exemption from the requirement to undertake the necessary seismic work to make their building no longer earthquake-prone.
Find out more: Guidance: Owners of Earthquake-Prone Buildings
If a territorial authority determines that a building is earthquake-prone, it needs to:
- Assign an earthquake rating for that building,
- Issue an EPB notice to the owner to display prominently on the building, and
- Publish the building information on the EPB register.
There are two categories of ratings for earthquake-prone buildings prescribed in regulations. These categories determine which form of EPB notice is issued:
- 0% to less than 20%
- 20% to less than 34%
Earthquake ratings are disclosed on the EPB notices and owners must display these in a prominent place. EPB notices also contain the deadline for owners to take action, by either strengthening or demolishing the building.
The territorial authority must also update the public EPB register to make sure that the public can access up-to-date information on which buildings have been identified as earthquake prone and also see their earthquake rating.
Related documents