The new First National Bank (FNB) head office in Freedom Plaza, Windhoek, will be Namibia’s first certified green building.

Apart from the sustainable use of urban space, the new FNB head office in Windhoek is envisioned to be “one of the country’s most innovative, sustainable and green buildings to date”, says Victoria Muranda, FNB Namibia corporate communications manager.

The bank’s project manager, Susan Fick, says FNB has been pioneering sustainability within the built environment before the Green Star SA system was adopted in South Africa – their iconic Fairlands FNB building serves as evidence of this, she adds.

A holistic and wide-ranging sustainability framework applies to the FNB Namibia development, which is being overseen by the Green Building Council South Africa (GBCSA).

“We’re developing a 4-Star rated building, featuring environmental best practice in design and construction,” says Cleo Forster, sustainability consultant at WSP Green by Design.

FNB Namibia’s divisions and business units are spread across Windhoek and “we want to change this,” says Muranda. “By consolidating, staff and management operations will be more effective and efficient,” she explains.

FNB Namibia’s vision is to develop a building that lessens the burden on the city’s civil and technical services, while honouring resource conservation through lowered consumption, re-use and recycling.

Water is key

Apart from water efficient fittings throughout the building to reduce water consumption, an intricate water re-use system has been developed to overcome the challenges of Namibia’s extreme low rainfall climate.

“All water from the building’s basins will be harvested by diverting the greywater flow from the municipal system and storing the water in the lowest basement level. The water will be treated through basic filtration processes and re-circulated to the building for re-use in the toilets,” explains Forster.
According to wet services engineer Trinesh Chanka of Izazi Consulting Engineers, “by implementing this re-use system, water savings are predicted at 2700L per day”.

A stormwater system different to the usual gravitational flow system – a Geberit pluvia roof drainage system – will be implemented. In this instance, the system is more economically efficient. Unlike conventional outlets, the Geberit pluvia system allows for greater discharge velocity and capacity, even with smaller pipe dimensions.

Civil engineer Tertius Basson of Windhoek Consulting Engineers says “the flash floods associated with this region means that a high stormwater flow is expected. Therefore different structures are needed than the usual gravitational stormwater system”.

The stormwater, to be used for landscaping, will be stored in the building’s lowest basement level. In diverting stormwater flow from the municipal system, geohydrological challenges had to be taken into account. “A sump pump will be needed when the water table rises to basement level,” explains Forster.

The sump water re-use system will be used during periods of low rainfall.

Variable air volume system and heat deflect ion

Cooling a five-storey building means significant energy consumption. Add Namibia’s extreme heat and it becomes a real concern. To overcome this energy challenge, “we’re implementing a decentralised variable air volume system”, says Clancy Mariette, mechanical engineer of Spoormaker & Partners.

The building’s mechanical systems have been designed to incorporate a full economy cycle, such as the flushing of cool air into the building at night, thanks to the fact that Namibia’s temperature drop considerably after dark.

A dark glowed facade will also deflect incoming heat. This curved, glazed facade features on the southern entrance of the building.

Waste recycling

With the majority of building material in Namibia being imported from South Africa, construction waste is already hugely reduced as quantities are closely specified, also for economic reasons. But as far as domestic waste is concerned, “we had to overcome the challenge of recycling in Namibia”, says Forster.

A solution was found in FNB offering startup support to a waste recycling service provider, contributing significantly to the formalising of Namibia’s recycling industry. “

Management systems and documentation

“Environmental management and auditing systems are not widely implemented in Namibia,” says Forster. “With this project, we’ve developed one of Namibia’s very first Environmental Management Programmes (EMPr).” This was entirely voluntary on FNB’s part.

Although the EMPr is notably generic compared to South Africa’s advanced environmental management industry, “it met standards”, says Forster. The EMPr addresses typical construction phase impacts such as erosion, storm water run-off and waste management.

Namibia’s emerging green building council

Frederick Muketi, chairman of the GBCN Associated Working Group explains that Namibia’s green building council is currently still emerging”. The request by FNB Namibia to certify their planned Windhoek head office expedited the development of the green building council. However, in order to do so, GBCN needed a rating tool that reflected the Namibian context. Fick says they knew they needed a very competent professional team to overcome the transformation hurdles.

Namibia’s local green building and construction context was identified and a Green Star

Local Context Workshop was undertaken with key Namibian stakeholders.

With this information, WSP Green by Design in collaboration with GBCSA and GBCN developed a Namibian context report.

The full feature appears in the June-July 2014 issue on page 26.