Earthquakes & Buildings
Selwyn District is within a high seismic risk area. We therefore need to have a way of identifying, assessing and managing earthquake-prone buildings to help ensure people and property stay safe in the event of earthquakes.
The way earthquake-prone buildings are identified, assessed and managed changed when the Building (Earthquake-prone Buildings) Amendment Act 2016 came into effect on 1 July 2017. The act applies to commercial buildings and some residential buildings. Residential buildings are only covered under the act if they are
- two or more storeys and three or more household units, or
- used as hostels, boarding houses or other types of specialised accommodation.
How earthquake-prone buildings are identified and managed
Council identifies buildings that may be earthquake-prone
You, the building owner, are informed of council findings
You need to have an engineer carry out a seismic assessment
A copy of the seismic report needs to be supplied by you to council
We will check the assessment and decide if the building is earthquake-prone
If your building is determined earthquake-prone
You either need to strengthen or remove the building within the specified timeframe
The Ministry of Business, Innovation and Employment have released a short informative introduction video on managing earthquake-prone buildings explaining why we have a national system, along with an overview of how it works.
Over the next few months you may start seeing earthquake-prone building notices going up on a few buildings within Selwyn. These buildings will be confirmed as earthquake-prone – see more details below on what this means.
What earthquake-prone means
A building or part of a building can be considered earthquake prone if
- the level of strengthening it has means it could fall down in a moderate earthquake, and
- if it did, it would be likely to cause injury or death to people in or near the building or on any other property, or damage to any other property.
Technically speaking, any building that has less than 34% of the required standards of the new building standard (NBS) is considered earthquake-prone.
We have identified buildings that have design features that are common in earthquake-prone buildings.
Where no records show that strengthening work has been done on these buildings we have contacted the building owners asking them to send us an engineer’s report by a specified date confirming if the building is earthquake-prone or not.
Building owners responsibilities
Where a building has been assessed as potentially earthquake-prone building owners will need to provide us with
- an engineering assessment meeting the requirements of the earthquake-prone building methodology, or
- further information to show that the building is not earthquake-prone.
If a building is earthquake-prone
Earthquake-prone buildings are not considered any more dangerous than they were before being identified, so business can continue as normal. What it does do is provide a timeframe for fixing up buildings to make sure they are as safe as possible during future earthquakes.
If the engineering assessment report shows that a building is earthquake-prone we will put up an earthquake-prone building notice. This will be prominently displayed on the affected building.
Under law the owners then have 15 years to strengthen the building or knock it down.
All confirmed earthquake-prone buildings will added to the national register of earthquake-prone buildings. We will carry out regular checks that the notice stays up and visible until the strengthening work is done or the building is knocked down.
What the earthquake-prone notices mean
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Buildings with an earthquake rating of 0% to less than 20%, or where no engineering assessment has been provided and the earthquake rating has not been determined.
The risk of failure for these buildings under seismic load is approximately more than 25 times the risk of failure for buildings that are 100% of the new building standard (NBS).
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Buildings that have an earthquake rating of 20% to less than 34%.
The risk of failure under seismic load is approximately 10–25 times the risk of failure for buildings that are 100% of the new building standard.
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Buildings or parts have been assessed as earthquake-prone, but owners are exempted from carrying out seismic work because the assessment shows a low risk for loss of life or damage to other buildings if the building were to fail.
What this means for the public
There’s no way of knowing for sure which buildings will fall down or be damaged in an earthquake. It’s possible a building that meets 100% of the building standards could still fall down.
The notice is there to help you make an informed choice about entering the building, or certain areas of a building, or not.
In any building, whether it has a notice or not, you should be aware of the safety procedures and what to do in an earthquake.
Heritage listed buildings identified as earthquake-prone
Heritage buildings are covered by the earthquake strengthening provisions of the Building Act 2004 in the same way as other buildings. Owners of heritage listed buildings are encouraged to work with Council’s heritage experts to achieve practical outcomes that preserves both public safety and the building’s heritage.
We have access to grants which may be you for
- repairs and maintenance, or
- paying for a conservation plan to provide guidance on the best way to strengthen a heritage building without compromising the heritage values.
For further information regarding a heritage listed building/structure please contact the Duty Planner via email@example.com or 03 347 2868.
Buying/selling/altering an earthquake-prone building
An earthquake-prone building can be bought or sold just like any other building.
The new owner will become responsible for the seismic strengthening. You should therefore carry out independent investigations before purchasing a property that is likely to be earthquake-prone.
Buildings being altered may need additional upgrade work carried out on them in additional to strengthening work. If so, this will relate to means of escape from fire and access and facilities for people with disabilities (see s133AT of the Building Act 2004 for details).
Disputing the earthquake-prone classification
You can challenge the classification of your building as earthquake-prone if you don’t agree with the initial seismic assessment (ISA) result. To do this you will need to provide your own engineer's report.
If an engineer has already carried out structural engineering design work on the earthquake affected building, then it will be best to use the same engineer to do an ISA review because of their existing familiarity with the building.
We will review the initial ISA based on further information you supply.
If you are still unhappy with our decision you can ask the Ministry of Business, Innovation and Employment to make a determination on whether your building is earthquake-prone.
Exemptions and extensions
You can apply for an exemption or extension for earthquake-prone buildings in some situations.
For an exemption from strengthening works for an earthquake-prone building you will need to show that your building is
- used infrequently, and
- poses a low risk of injury to people and damage to other property in the event of an earthquake.
You can make an application for a 10 year extension to complete strengthening works for an earthquake-prone building that is
- a Category 1 listed building, or
- on the National Historic Landmarks list.
For either you will need to apply in writing with reasoning to justify your request to firstname.lastname@example.org
What to do following an earthquake
Building owners need to develop their own internal policies and procedures for their building after an earthquake. All tenants must be aware of these processes and know what to do before an earthquake happens.
Anyone running a business is required by law to provide a work environment that has no identifiable risks to health and safety. The Health and Safety at Work Act 2015 doesn’t set a minimum standard – but says that all practical steps are to be taken to remove or minimise the risk from identified hazards.
Following a significant seismic event, Council recommends that building owners/operators get buildings assessed for potential structural damage that may have been caused by the earthquake.
The following four-step approach will help you work out if buildings are safe.
- Initial assessment by owner/operator
- If this finds significant issues/damage then further assessment is needed – hire a chartered professional engineer if there is any doubt
- Don’t allow anyone to enter the building if there’s any concern about the structural integrity of the building and seek professional chartered engineering advice and guidance.
- Chartered engineer inspects key parts of the building structure – this may include invasive techniques
- Do not enter the buildings until the engineer declares that it is safe to occupy.
Check building systems
- Once the building is declared safe to occupy, organise an inspection of building services and systems by suitably qualified professionals/Independent Qualified Person – eg fire protection, electrical, water, lifts, heating and air conditioning, or security
- If any services/systems are damaged, you may not be able to occupy the building until they are fixed
- Carry out repairs on any other damaged areas identified
- Carry out a final check to ensure that the building is safe to occupy in line with the building warrant of fitness and building code regulations and policies.
All clear to occupy
- Building is cleared and fit to reoccupy. For more information see the building owner and manager post emergency guide.