Earthquake Prone Buildings
Selwyn District is within a high seismic risk area. With this in mind, we 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 this needs to be done within set timeframes.
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:
- comprise two or more storeys and three or more household units, or
- are used as hostels, boarding houses or other types of specialised accommodation.
Guide to earthquake-prone buildings process
Council identifies buildings that may be earthquake-prone
Building owner informed of Council findings
Building owner commissions engineer for a seismic assessment
Building owner supplies copy of seismic assessment reports to Council
Council checks the assessment and decides if the building is earthquake-prone
Council will place a notice on buildings determined as earthquake prone, and adds the building to the national register of earthquake-prone buildings
Building owner either strengthens or removes 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 buildings in the Selwyn district. This is because the Council is receiving reports confirming the earthquake-prone status of buildings. Below we have covered off further information that you may find helpful in answering any questions.
What earthquake prone means
A building or part of a building can be deemed 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 persons 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 in the new building code is considered earthquake prone.
The Council has identified buildings that have design features that are common in earthquake prone buildings and no records show that strengthening work has been done on the buildings.
We’ve contacted these building owners requiring them to send us an engineer’s report by a specified date confirming if the building is earthquake prone or not.
Building owner's responsibilities
Where a building has been assessed by Council as potentially earthquake prone, building owners will need to provide to Council an engineering assessment meeting the requirements of the EPB 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 shoring 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 Council will put up an earthquake prone building notice. This will be prominently displayed on the building affected.
Under law the owners then have 15 years to strengthen the building or knock it down and Council will work with them to ensure that happens.
The building will added to the national register of earthquake prone buildings. Council will check that the notice stays up and visible until the strengthening work is done or it’s knocked down.
- Orange and black striped border – 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.
If the building has an earthquake rating of less than 20% the risk of failure under seismic load is approximately more than 25 times the risk of failure for buildings that are 100% of the new building standard (NBS).
- White and black striped border – 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% NBS.
- Orange and white striped border – buildings or parts assessed as earthquake prone but owners 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 if you want to go into 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.
Council has access to grants which may assist with repairs and maintenance or pay 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 firstname.lastname@example.org or 03 347 2868.
Buying/selling/altering an earthquake-prone building
An earthquake-prone building can be bought or sold.
The new owner will become responsible for the seismic strengthening, therefore it is recommended that purchasers undertake independent investigations prior to purchasing a property that is likely to be earthquake-prone.
Buildings being altered may require additional upgrade work carried out on them in additional to strengthening work in respect of provisions relating to means of escape from fire and access and facilities for people with disabilities (refer s133AT of the Building Act 2004 for details).
Disputing the earthquake-prone classification
The classification of a building as earthquake-prone can be challenged. Building owners will need to produce their own engineers report in order to challenge the initial seismic assessment (ISA) result.
If an engineer has already carried out structural engineering design work on the earthquake affected building, it is likely that the same engineer should do an ISA review because of their existing familiarity with the building. Council will review the initial ISA based on further information you supply.
If you are still unhappy with Council’s 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
Building owners can apply for an exemption or extension under certain circumstances.
Application can be made for an exemption from strengthening works for an earthquake-prone building that is:
- used infrequently
- poses a low risk of injury to people and damage to other property in the event of an earthquake.
An application can be made 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.
Send your application in writing with reasoning to justify your request to email@example.com.
What to do following an earthquake
Building owners need to develop their own internal policies and procedures. All tenants must be aware of these processes and know what to do prior to an event.
Anyone running a business is required by law to provide a work environment that is without identifiable risks to health and safety. The Health and Safety at Work Act 2015 does not set a minimum standard, rather it says that all practical steps are taken to remove or minimise the risk from identified hazards.
Following a significant seismic event, Council recommends 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.
1. Initial assessment
- Initial assessment by owner/operator
- If this finds significant issues/damage then further assessment is required – hire a chartered professional engineer if there is any doubt
- Do not allow anyone to enter the building if there is any concern about the structural integrity of the building and seek professional chartered engineering advice and guidance
2. Engineer inspection
- Chartered engineer inspects key elements of the building structure – this may include invasive techniques
- Do not enter the buildings until the engineer declares that it is safe to occupy
3. 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, e.g. 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 accordance with building warrant of fitness and building code regulations and policies
4. All clear to occupy
- Building is cleared and fit to reoccupy.