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Environmentally Sustainable Design Considerations

Management

The building was constructed in accordance with a site-specific environmental management plan. Decision-makers in the project have a record of sustainability achievements and credentials.

Steps have been taken to ensure management of the environmentally sustainable design initiatives incorporated into the design are maintained throughout the building’s operational lifetime. Before moving into the premises, staff members were briefed about the sustainability initiatives incorporated in the building, how these systems work, and ways to maintain the sustainability of the building.

Energy

The building was modelled to determine the benefits and paybacks of insulation levels. This was done to achieve a good balance between extra insulation levels (90mm) and the need to prevent the building overheating as a result of human activity and waste heat from office equipment.

The building is operating and producing heat and light 24 hours a day, 6 days per week. The mail processing machines generate a lot of heat. The result is that it is often beneficial for the building to lose heat rather than capturing it, because insulation would trap the heat and then require more energy to be expended on cooling.

The air-conditioning system has outdoor air economy cycle operation. This reduces the mechanical cooling load when outdoor air temperatures are between 12°C and 20°C and cooling is required. Fast-acting doors to the staging areas help prevent heat loss as people circulate in and out.

Low-energy light fittings, light zoning with motion sensors in main areas, photocell switching in perimeter areas, timers, and separate switching all provide savings throughout the building and ensure only occupied areas are lit. Low-energy equipment, such as dishwashers and fridges, have been specified throughout.

Solar hot water panels are provided to reduce water heating requirements.

Photo of a solar hot water system on the roof of the building.

Solar hot water system on the roof. Photo courtesy of New Zealand Post.

Water

The building provides reduced levels of water consumption compared to previous New Zealand Post buildings. To achieve this, the building uses a number of systems.

  • Rainwater harvesting for ‘grey water’ uses 840m2 (15 per cent of the total roof surface) with three collection tanks totalling 75,000 L. This will easily cover all annual toilet flushing requirements for the building as 750m3 per year of water is estimated for toilet flushing, with a possible 990m3 of water being reclaimed from rainwater.

  • Water meters have been installed on the flushing water systems to allow user monitoring of volumes and any make-up with potable water.

  • Estimated water savings total $1000 per year. This number is low, mainly because there are no sewage discharge costs for Hamilton (which could change in the future).

  • AAA-rated plumbing fittings, which can reduce water demand by 33 per cent.

  • Increased on-site stormwater management through permeable paving to selected car park areas to reduce stormwater run-off, and rain gardens and drainage swales wherever possible.

In addition to water consumption savings, the water-efficient devices employed lead to a reduction in emissions to the sewer, which decreases both pressure and reliance on local infrastructure.

Photo of rainwater tanks.

Rainwater tanks. Photo courtesy of New Zealand Post.

Photo of stormwater swale.

Stormwater swale. Photo courtesy of New Zealand Post.

Indoor Environment Quality

Evaluations were carried out to ensure best fit between natural ventilation opportunities, mechanical ventilation and temperature control, as well as filtration requirements to prevent dirt and dust in processing areas. Wherever it was not possible to provide natural ventilation, mechanical units with outdoor air economy cycle operation have been provided. This helps reduce the mechanical cooling load, and allows for fresh air to be introduced when outdoor conditions allow, so improving indoor air quality.

Additional features aimed at improving indoor environmental quality include:

  • horizontal shading of windows to office areas

  • maximising natural light to the processing hall with a glazed wall, while making due consideration for low afternoon sun

  • roof lights to the interchange area

  • low VOC paints

  • natural ventilation and fresh air supply beyond national requirements.

Materials

Materials have been carefully selected throughout the building, giving preference to recycled content, low-VOC emissions and sustainably sourced timber. Examples include:

  • recyclable and modular carpet

  • linoleum in lieu of vinyl wherever possible (to reduce the effect and use of possible harmful chemicals)

  • sustainably sourced timber

  • Environmental Choice paint systems

  • ceiling tiles with high recycled content

  • New Zealand-manufactured hardware.

Waste Minimisation

During construction: A single centralised area was established on site for separating and storing waste before recycling or disposal to landfill. At least one representative from each subcontractor attended a training workshop run by the contractor during the construction phase to learn the methods and practices of waste minimisation.

A system was implemented to ensure compliance with all statutory and regulatory requirements relevant to the disposal of toxic and non-toxic waste materials.

In use: Waste separation has been included in kitchens, and recycling ensures good practice.

Transport

Bicycle stands have been provided for both staff and public use.

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