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Architect’s render of the Bay of Plenty Regional Council’s $25 million redevelopment of Regional House in the Tauranga CBD – Image courtesy of Chow:Hill

Green upgrade for council’s Tauranga office

Innovative sustainability features are the hallmark of the Bay of Plenty Regional Council’s $25 million redevelopment of Regional House and the adjacent Wallingford House in the Tauranga CBD.

A wind turbine, solar power and rainwater harvesting for toilet flushing are some of the energy-saving features being incorporated into the upgrade. There is also smart LED lighting with daylight harvesting and occupancy sensors, and electric car charging stations in the car park.

A leading-edge ‘fibre to the desk’ communications system will provide super-fast internet speed and future flexibility. Promoting energy savings for the occupants, real-time energy usage will be screened in the main foyer.

Due for completion later this year, Regional House will contain council offices and meeting rooms on four of its six floors. The adjacent two-level Wallingford House will house the Group Emergency Coordination Centre (GECC) with proximity to many of the Civil Defence partners such as fire, police and the council’s maritime team, which will house its vessels on the ground floor of the waterfront site.

Key challenges

Tauranga-based Bradley Cooper is the buildings and infrastructure manager for Harrison Grierson, the engineering and design consultancy with responsibility for both the structural and building services design and installation for the project.

As project manager, Bradley collaborates closely with architects Chow:Hill and contractors Canam Construction. He says the key challenges have been identifying the structural deficiencies within the existing buildings, and working with the client and architect to design a cost-effective, practical buildable solution for both the buildings.

“The design team worked closely together to ensure that not only is it structurally sound, but that any strengthening also fits within the architectural vision for the refurbishment. The structural strengthening of Wallingford House was an additional challenge for our engineers, given the particularly stringent requirements in its role as the GECC.”

Seismic strengthening

As well as new and upgraded building services, seismic strengthening has been undertaken, achieving a 100% new building standard (NBS) rating at importance level 2 (IL2) for the 1986-built Regional House.

Using 3D modelling, Harrison Grierson identified there were issues with seismic joint construction around the building’s toilet block and stairwell areas, and that without upgrading it would fail to reach current NBS. Structural engineers designed a simple and effective solution of introducing new movement joints at key locations in the structure, in conjunction with utilising carbon fibre sheets, fixed to the walls to provide the additional strength required to achieve 100% NBS.

As a dedicated Civil Defence emergency coordination centre, Wallingford House required upgrading to the extremely stringent IL4 seismic code category. Natural hazard modelling undertaken by Harrison Grierson has established that the structural upgrade to Wallingford House will ensure it can handle severe earthquakes, all while maintaining functionality as a post-disaster relief headquarters.

The building will accommodate an emergency response centre with sewer retention and water storage systems, and an essential generator system with bulk fuel storage for continued use during an emergency situation. Harrison Grierson leveraged the building’s proximity to Regional House to incorporate sustainable design into these features.

Promoting energy savings for the occupants, real-time energy usage will be screened in the main foyer

Energy savings

Jono Smith, Harrison Grierson’s senior electrical engineer who has worked on the design and installation of the services since 2016, says many of the project’s green features were included in the company’s design work from the outset. But the fibre to the desk has been a new initiative and is particularly exciting.

“Taking fibre straight from the street direct to the desk means there’s significantly less cabling involved and no need for the usual cable trays and equipment you typically see in an office situation. The challenge is that, in an existing building, you don’t know what you’re going to find.”

Jono estimates the arising energy savings will be around 30% of the usual energy lighting for a similar-sized building. Energy savings overall are anticipated to drop from the current 200 kWh per sq m per year to 100.

In the future, Jono aims to assess the performance of the building by completing a NABERSNZ energy-efficiency rating, ensuring the building is operating as designed. The sustainability initiatives are forecast to reduce the building’s carbon emissions from 100 tonnes to 50 tonnes per annum.

Another challenge was ensuring that Vodafone, a tenant in Regional House, was not disrupted with the works, as it provides the central hub in Vodafone’s distribution network for its north-south link. Harrison Grierson designed a replica IT room within the basement of the building, allowing Vodafone to transfer their services with minimal downtime, while maintaining continuity of service during construction.

Future-proof

Annabel Chappell, Bay of Plenty Regional Council’s Te Tuara manager, says the upgrade was included in the council’s long-term plans 2015-2025 and 2018-2028. Around 180 council staff will work from the upgraded Regional House, bringing together staff from four locations across Tauranga and Mount Maunganui.

Annabel says the redevelopment successfully reflects the council’s environmental values, and the council and ratepayers will be very proud of it for many years to come. “We’ve looked to the future by working with Tauranga City Council to align our redevelopment with its vision for the city centre. Importantly, we’ve future-proofed our council’s key hub and our emergency response centre in an environmentally friendly and sustainable way.”


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