Public Works office first to receive five-star green star SA rating

"We applaud the KZN Department of Public Works' commitment to sustainable development and the leadership role it is taking," said Brian Wilkinson, CEO of the GBCSA. "As the largest building owner in South Africa, the state has the potential to make a significant positive difference to the environmental impact of the built environment in South Africa. Apart from being a provincial government first, this achievement is especially important as it will surely encourage other government departments to strive for best practice in green building."

First of four phases

The final cost of the new building was about R21 million, which is about 1.5% more than a conventional building would have cost, but the long-term savings through energy and water efficiency will more than balance out the additional expenditure.

The office consists of two single storey buildings, and is the first of four proposed phases of development on the 7.6 hectare site, to be followed by additional office space. The site was previously unused and overgrown with invasive alien vegetation. The remainder of the site has been landscaped to return it to its endemic mistbelt grassland habitat.

The green office embraces sustainable design principles by addressing energy, water, waste, transport and indoor environmental quality issues, to ensure a comfortable, healthy indoor environment for occupants, as well as a lighter footprint on the surrounding environment.

The building reduces energy consumption by taking advantage of natural daylight to minimise the amount of electrical light needed. Natural air-flow is also maximised in the building, and it does not require mechanical air conditioning. In winter, the building is heated through warm water pipes under the floor, and this water is heated using an energy efficient heat pump. Solar water geysers are also used to provide hot water.

Water consumption is monitored

The lighting systems have been designed using high efficiency lights, and fitted with motion sensors. Areas or equipment that use a lot of energy are monitored, allowing the building operator to measure energy use and identify possible savings.

The green office is equipped with water efficient fittings that can save up to 70% of water consumption. Water metering also allows for monitoring of water consumption, and rainwater harvesting assists with washing cars and flushing toilets, and also reduces the run-off from hard surfaces during a storm event. This reduces the negative effects on nearby water courses.

One of the most striking elements of the Sisonke office is the extensive roof garden - home to over 70 endemic water-wise plants. They only require a thin layer of soil to grow, and don't require significant additional structural reinforcing to accommodate the extra weight of the gardens.