Technical Specification For The Design Of New Buildings Out For Public Comment

Standards New Zealand has today released a draft Technical Specification for Structural design actions – Part 5: Earthquake actions – New Zealand (TS1170.5) for public comment. The draft specification looks to provide updated engineering guidance to determine earthquake loadings when designing new buildings.

“Standards New Zealand and Engineering New Zealand were commissioned by the Ministry of Business, Innovation and Employment to develop a draft Technical Specification incorporating the science and insights gained from the updated 2022 National Seismic Hazard Model (NSHM),” said Malcolm MacMillian, National Manager, Standards New Zealand.

“The draft Technical Specification has been developed through a robust process using the skills, knowledge, and experience of a committee of technical experts from across the building industry. We now welcome others to review the proposed draft and provide their feedback. Public comment will run for a four-week period” says MacMillian.

“Once published, a Technical Specification should typically be reviewed after three years to decide whether to extend its use for a further three years, revise it, withdraw it or develop it further to become a standard.”

The Ministry of Business, Innovation and Employment is encouraging people from across the engineering, building and property sectors to provide input into the public comment process being run by Standards New Zealand.

“The current earthquake loading requirements for new buildings are not changing with the release of this Technical Specification. Once published by Standards New Zealand, it will be able to be used by designers on a voluntary basis as one way of demonstrating compliance with the performance-based Building Code, through an alternative solution” said Dave Gittings, Manger Performance Building and Engineering, Ministry of Business, Innovation and Employment.

“It’s important to note that the Technical Specification does not change the requirements of the earthquake-prone building (EPB) system. All seismic assessments, including voluntary seismic assessments, follow the same approach as for the national earthquake-prone building system and use the current standard NZS 1170.5:2004,” says Gittings.

The draft Technical Specification is a technical document. It has been developed to help engineers and designers voluntarily incorporate, into their designs, the results of new science in the NSHM. If the specification is followed, new buildings will be able to better withstand the range of earthquake shaking expected in different areas of New Zealand.

“The draft specification is intended for most new buildings such as offices, commercial buildings, and apartments. Other buildings, such as dwellings and timber framed buildings up to two storeys’ high are generally not affected because a different design standard is typically used.”

“The use of a technical specification provides the framework to ensure that technical content being proposed is adequately ‘road tested’ by New Zealand engineers, with the opportunity for them to provide feedback before the information is published in a New Zealand Standard or considered for inclusion into the Building Code,” says Gittings.

The draft Technical Specification 1170.5 can be found on Standards New Zealand’s website here. Public comment closes on 14 March 2024.

NOTE TO THE EDITOR

· The Ministry of Business, Innovation and Employment’s Building System Performance (BSP) is responsible for managing Aotearoa New Zealand’s building laws and regulations that protect public safety and property. They provide building practitioners, officials, consumers, and other regulators with regulatory frameworks and guidelines and information about their roles and responsibilities.

· Standards New Zealand is a business unit within the Ministry of Business, Innovation and Employment. It is New Zealand’s independent and internationally recognised national standards body. It manages the development and publication of national and regional standards and standards-related solutions under its own legislation.

· The National Seismic Hazard Model calculates the likelihood and strength of earthquake shaking that may occur in different parts of Aotearoa New Zealand over specified time periods. It is used to improve our resilience and manage risks to safety, security and the economy from seismic events NSHM - National Seismic Hazard Model - GNS Science | Te P Ao.

· The updated 2022 National Seismic Hazard Model highlighted that seismic hazard was higher almost everywhere throughout Aotearoa New Zealand than we previously understood. Overall, it indicated an average increase in earthquake hazard of around 50 per cent or more across the country relative to the previous model from 2010.

· When the updated National Seismic Hazard Model was released in 2022, the Ministry of Business, Innovation and Employment advised New Zealanders that it would look into the implications of the updated model although it would not immediately change the way buildings were built and designed in New Zealand.

· Working with Standards New Zealand on the Technical Specification project has allowed technical experts to determine the best way to use this important science to improve the resilience of new buildings.

· The proposed Technical Specification does not change the requirements of the earthquake-prone building (EPB) system. The EPB system continues to use the seismic hazard specified in B1/VM1 on the date the legislation came into effect, which was 1 July 2017 (i.e. NZS 1170.5:2004).

· MBIE’s advice is that all seismic assessments, including voluntary seismic assessments outside the EPB system, follow the same approach as for the national earthquake-prone building system i.e. continue to use NZS 1170.5:2004.

· Once published, a Technical Specification will typically be reviewed after three years to decide whether to:

o confirm it for a further three years

o revise it

o process it further to become a New Zealand Standard

o withdraw it.

· MBIE will be collecting feedback on the use of the Technical Specification 1170.5 to inform any future decision on citing it in the Verification Method to the New Zealand Building Code.

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