The new head office project for the Department of Environmental Affairs, designed by Boogertman + Partners, in Pretoria has been awarded a six-star Green Star South African Office Design V1 rating by the Green Building Council of South Africa.
The new Department of Environmental Affairs (DEA) head office in Pretoria, designed by Boogertman + Partners, is rapidly burgeoning on the Pretoria skyline. The building recently received the first six-star Green Star South African Office Design V1 certification from the Green Building Council of South Africa (GBCSA) for a government building and it is set to achieve a six-star “As Built” rating once completed.
The site location, which is bound to the east by Steve Biko Street, to the north by Soutpansberg Road and to the west by Oumashoop Street in the suburb of Arcadia, is seen as a gateway to Pretoria’s inner city.
The design brief that was given to the architects, was to create a new office that communicates an architectural language which reflects the Department’s environmental and sustainable ideologies.
“The DEA requested that the architecture of the building needs to express the core values of the DEA and its willingness to live up to its environmental values to the public as well as building users. We needed to clearly demonstrate aspects of sustainable design, energy and resource efficiency,” says Lood Welgemoed from Boogertman + Partners.
The architects needed to provide an environmentally-friendly building with sufficient energy-efficient equipment, energy-saving devices and water-saving devices with adequate energy-efficient cooling throughout the year.
“This is an exceptional illustration of the public and the private sector working together to deliver an outstanding example of green building,” commented Brian Wilkinson, chief executive officer of the GBCSA, before explaining that the six-star rating is the highest GBCSA score achieved by a commercial office space of this magnitude, which includes a lettable area of 27 422m².
Facts and figures
Size: 30 654m²
Cost: R653 million
Timeframe: July 2012 to July 2014
Project developer: Imvelo Concession Company
Architect: Boogertman + Partners
Quantity surveyor: Pentad
Consulting engineers: PD Naidoo and Associates
Facilities manager: Imvelo Facilities Management
Green Star SA-accredited professional: PD Naidoo and Associates
Natural lighting and ventilation
The general height of the building was kept to three storeys. Each office wing received a central atrium and clerestory windows above the roof to enhance natural light in the building.
“Lightly tinted, double-glazed units with high luminous efficacy were also installed to ensure good daylight penetration without the heat energy. Electric lighting energy load is drastically reduced by BMS-controlled light fittings, which only come on when required,” adds Welgemoed.
Natural ventilation and night flush ventilation are also encouraged through the stack effect that the architects employed, which will reduce the client’s need for artificial cooling during the summer months. The company also took an innovative approach with regards to air-conditioning units.
“Air-conditioning units are provided via a roof-mounted evaporative cooling plant, making it possible to open windows while the air-conditioning is on, under the right circumstances. Passive ventilation is used through exposed concrete soffits which absorb daytime heat energy, which is then automatically flushed at night,” explains Welgemoed.
Another green addition to the roof is roof-mounted photovoltaic cells that will provide for in excess of 10% the annual energy load to the building. The highly innovative roof is also insulated on top and the high-tech waterproofing membrane is solar reflective.
Solar water heaters at roof level ensure that water heating in the building through carbon based energy is limited.
Rain water and grey water is harvested in basement tanks and reused, giving a 30% water saving.
Building orientation and indoor air quality
The design team also used comprehensive energy modelling in order to determine the best building orientation. Office wings are placed on an east/west axis with solid east and west walls, shaded northern facades and less shaded but glassy south facades.
“This orientation ensures the best combination of external shading versus daylight requirements, glass specification and glare control,” explains Welgemoed.
Sustainable insulation measures
Insulation is provided to the building envelope through:
• Off-shutter concrete walls and columns.
• Insulated terracotta clad rain screens.
• Masonry walls.
• Insulated double glazing.
The architectural vision and mechanical design of the building aim to ensure optimal indoor environmental quality for those working inside the building in order to promote health and well-being. The selection of finishes used on the project therefore plays an integral role in ensuring responsible resource management.
A full cradle-to-grave lifecycle assessment (LCA) was done to ensure that informed decisions were made in terms of everything from the resource-extraction phase to the use and disposal phases.
Material and product selection
When commenting on the product selection criteria and vetting, Welgemoed explained that all aspects of the project need to be considered.
“Examples of this can be found in the use of sprayed-on polymeric external coatings instead of ordinary paint, large expanses of off-shutter concrete, unglazed terracotta cladding and the use of powder-coated aluminium. Internally, the shop-fitted items are all hardwood veneered or lacquered, full-bodied porcelain tiles are used extensively in the communal areas and high-quality carpet tiles are specified for the office areas,” says Welgemoed.
“In sustainable product selection, form follows function. Performance is a crucial aspect of material selection and what the performance requirements are, dictates the products you will use. Accessibility, durability and workmanship are all aspects we take into account in specifying for our hi-spec buildings. We specified insulation for this very reason and the fact that it does not contain any HCFCs or HFCs, which is in line with the DEA’s present HCFC phase-out programme,” adds Welgemoed.
The new DEA building sets out to embody the sector’s dedication to sustainable design and the benchmark for the future of green building in South Africa. As more municipalities and governments adapt green building practices as part of their code, it becomes more of a requirement and less of a luxury – it becomes the definition of good design.
“The architectural team believes that we have not only met but exceeded the requirement and simultaneously created a beautiful building which will inspire all who work and visit there,” concludes Welgemoed.
For more information, visit www.boogertman.com and www.gbcsa.org.za, to who full thanks and acknowledgement are given.