As the New Zealand sustainability lead at engineering consultancy Norman Disney Young, Hayley Koerbin was deeply involved in the myriad of decisions required to ensure The Hotel Britomart achieved a 5 Green Star rating for its design and build. Here, she explains to Jeremy Hansen how Green Star ratings require consideration of every aspect of a building’s construction and operations − and how these decisions benefit the environment.
Jeremy Hansen Firstly Hayley, can you describe your job?
Hayley Koerbin I lead the New Zealand sustainability team at Norman Disney Young within our global sustainability group. We work across all regions and all sectors. We look at environmental sustainability: reducing energy use and carbon emissions, as well as social and governance sustainability such as occupant experience, health and wellbeing.
How did you get into this role?
I studied Building Science and majored in Sustainable Engineering Systems at Victoria University of Wellington. Eight years ago I moved to Melbourne and worked in this field there. I moved back to New Zealand almost two years ago. New Zealand has historically been behind Australia regarding sustainability in the built environment, so it means there’s huge potential.
What does it mean for a building like The Hotel Britomart to have a 5-star Green Star rating?
If we look at Green Star it’s a very holistic tool. To have that third-party assessment and certification is ensuring you’re delivering on what you set out to do in the first place. Historically, things have fallen down during construction when there’s no proof that what is designed is actually built. Green Star allows us to verify these outcomes through tangible assessment methods, and set the building up to operate in a sustainable way.
What does a Green Star rating show to a potential user of a building?
That [the building’s developers are] looking to reduce the impact of climate change. It’s enhancing our health and quality of life. The tool asks that we look at restoring our biodiversity, our ecosystems, that we drive resilient outcomes and contribute to better communities, market transformation and a sustainable economy. Green Star enables us to benchmark data through modelling processes and product selections, how much energy have we saved and how much water use we have reduced. We can convert that to something the general public really understands. There are a lot of technical elements but everything has a very clear intent and outcome that relates to a positive impact on the environment and human health and wellbeing.
So what can I be assured of as an occupant of a Green Star building?
It depends on what credits the building has targeted, but one of the things that people notice first is a better indoor environmental quality. Daylight, high-quality light fittings – you may notice after a reasonable amount of time that you’re not getting eye-strain, headaches or sneezing – you will feel a lot healthier in that space.
Why isn’t every building required to have 5-star Green Star certification?
There are no government or property council regulations in New Zealand around this which does make it a bit difficult. A lot of clients see cost as a barrier. We try to guide them through the process – if you think about the building and design it well from the beginning, you won’t see a huge increase in costs. We work to make sure these features are integrated into the design, rather than being an additional add on (and then cost) at the end of the process. People are starting to realise the benefits and how they translate to users of the space, and will make decisions based on that.
What are some highlight achievements of The Hotel Britomart, in your opinion?
Green Star certification applies to almost every decision made during construction, but there are a few that provide really clear examples of the difference a Green Star process can make. One of them is recycling or reuse of construction waste – the industry benchmark is for 70% of construction waste to be re-used or recycled, but The Hotel Britomart has achieved almost 80%, which is huge. Part of it is designing to minimise construction waste in the first place, then careful management on site to ensure that items are used efficiently and sorted correctly before going off for recycling.
The efficient design of the building avoids excessive heat gain or loss and means that we expect the building to have ~50% fewer greenhouse gas emissions than a building that meets the minimum requirements of the New Zealand building code. That’s a huge improvement. We’re also providing double the minimum requirements of fresh air specified in the building code, so there is less carbon dioxide in occupied spaces and people will feel more alert.
Although we have used concrete in the building’s construction which typically is a very carbon-intensive material, the team has worked hard at minimising its environmental impact. That means at least 50% of the mix water for all concrete used in the project was captured or reclaimed water, and we’ve also ensured 60% of the coarse aggregate used in roading, footpaths or parking outside is recycled, recovered or secondary aggregate.
Those are some of the highlights, but I don’t want to underplay the huge range of attention to detail in other areas too – from the provision of flicker-free lighting (which makes people feel better in a space if they’re there for longer periods of time) and access to natural light, to the use of environmentally friendly paints and other coatings. All the timber used in the building is responsibly sourced and has a low environmental impact. All the taps and other fittings are highly efficient with their water use. The list goes on – and every element of the list is checked, so everyone knows The Hotel Britomart will be meeting the standards it set itself.