dendrite studios

So climate change is a reality, water scarcity in the Western Cape a big risk, urbanisation an accelerating international trend and Cape Town still sit with pronounced economic inequality. Now what?
According to Sym van der Ryn, “the environmental crisis is a design crisis. It is a consequence of how things are made, buildings are constructed, and landscapes are used.” Session three of our ‘How do we build well in a changing climate’ series therefore started to look at some responses to the ecological challenges we face with the session entitled New Design Parameters. Two very renowned Cape Town architects in the persons of Gita Goven and Alex Robertson were the evening’s main contributors.

Gita Goven is a partner at ARG Design and is also the chairperson of the Sustainability Institute in Cape Town. Gita has been working in the field of sustainable design for many years and some of her practice’s projects have received multiple accolades. Gita entitled her presentation: Adamator Standing Guard – How can design support a new vision of Cape Town as an ecological city? The 5 main points she highlighted that must be addressed in order to achieve this are:

• Integrate urban design, planning & biodiversity in repositioning the spatial & economic apartheid city
• Balancing mixed use, mixed income & medium density with ecosystem functions of land use
• Decrease resource flows in the urban terrain
• Understanding the relationship between settlement, livelihoods & conservation
• Developing performance measures such as Green Coefficient (similar to genie coefficient) and ecological footprint.

There is a very good rationale for establishing Cape Town as an ecological city given its truly unique climate and biodiversity. It is one of only six Mediterranean regions on the planet and of all these it has the greatest biodiversity per hectare. Coupled with the breathtaking scenery it is one of the most sought after urban areas in the world.

Gita then gave an overview of some of the parameters they considered in their work on the Driftsand Nature Reserve on the Cape Lowlands. Earlier on she referred to the Cape Lowlands as the gardens of Adamastor. She also referred to some conceptual work they did for an upgrade of the Kosovo Informal Settlement. This includes different housing typologies and a different hierarchy of spaces. The proposal also includes a biogas & waste treatment site and an area for urban agriculture. As a final case study she looked at the Tsoga Environmental Centre. As opposed to most buildings where a significant amount of material and finishes are important from Europe and Asia, in this building they tried to maximise the use of local building materials. This included ceilings from locally grown latte, room dividers woven from local riet, foundation material from brick recovery process and a succulent covered earth roof on poles. Tsoga stands as a proud beacon of what can be done in informal settlements such as Samora Machel. (This projected received a Bronze Medal in the Holcim Sustainable Building competition.)

In conclusion Gita mentioned the following tools, targets & benchmarks that should be considered in sustainable design:

• Cities as managed ecologies;
• Design for climate change & mitigation;
• Ecological footprint and carrying capacity;
• Resource use regeneration and management;
• Waste as nutrients;
• New economic valuation techniques; and
• Incorporation of scientific and traditional knowledge.

Alex Robertson who is a retired partner at a leading Cape Town architectural firm has for the last couple of years acted as an architectural consultant to clients in the private and public sector. It was in this capacity that he became the consultant for BP South Africa when they were looking for a new head office in Cape Town.

In his presentation Alex focussed on the site selection process of the new BP head office and the design brief of the project. One of the important aspects of the brief was that BP wanted a building to reflect their environmentally responsible philosophy but the building should not cost any more than a typical A-grade office space. To achieve the former environmental consultants ARUP were tasked to compile a Resource Efficient Design (RED) brief calling amongst others for the use of recycled material, minimising pollution and having about a third of the energy consumption of similar buildings.

To do all of this at the normal budget required serious thinking, research and very clever design. After an architectural ideas competition, KrugerRoos Architects & Urban Designers got awarded the contact and the end result is arguably still the country’s leading ‘green’ commercial office complex.

Alex focussed on some of the efficient design characteristics of the BP building including: ventilation stacks at the building’s outer edges to allow airflow; double-glazed windows that are deeply-recessed reducing solar heat in summer while enabling sun penetration in winter; light shelves in the recesses providing extra shade from the heat while at the same time allowing light to be bounced deep into the interior; a huge central atrium for natural light, and; motion sensor controlled lighting. Besides these features, the building also boasts with a 1,3 million litre underground water tank that stores run-off water from the roof area and is used for irrigation. The photo-voltaic panels on the roof are the only efficiency feature that was brought in as an extra and was done by BP to make a statement about their intent. The PV’s were designed to provide 10% of the building’s electricity. Overall, the RED brief intended for the building to consume only 115 kWh/m2 of electricity per year. This is in contrast to similar buildings’ consumption of 350kWh/m2. *

According to Alex, these electricity targets have not yet been reached and there have been problems with the PV’s for example. But, the important factor is that there have been huge efficiency gains and that much has been learned through the project. The goal is thus to improve on every building and to design so that improvements can still be made throughout the lifetime of a building. Owing to constant improvements in renewable energy technology and greater experience in South Africa, it is now possible to make every building ‘greener’ than the previous one.

The BP head office in the V & A Waterfront is an A-grade office complex of international quality and is significantly ‘greener’ than its peers. One should be realistic about the commercial realities and demands of clients and owners and there will most often, as was the case on several aspects with BP, be compromises made. These compromises are unfortunate, but as long as every project improves from the previous ones, and does all the basic things right, we will already go a long way towards ‘building well’.

*ADMIN: A calculation on the saving between normal (350kWh/m2) and current BP electricity use (200kWh/m2) assuming a 9% electricity inflation and an area of 10 000m2 shows a saving in electricity bills of R4,2 million over a 20-year period using the net present value (NPV) method.

Some of the questions that got raised during the Q & A include:
Q: Was car use part of consideration in design of BP building?
AR: The first consideration was a suitable site and the one in Waterfront was chosen for various reasons. This meant that the building would not be as close to public transport as the old Head Office. At the time of planning, there was however advanced plans for a modern bus service between the city centre and the V & A but nothing materialised.

Q: Resource use on BP building is still extensive. Was retrofitting considered?
AR: Although the owner of the building that housed the previous temporary office was keen for that, the building was just not suitable. Furthermore there was no interim place were the staff could go to while retrofitting occurred.

Q: How do you bridge the gap between people’s aspirations and green technology?
GG: Much has to do with engaging in a consultative process and education. The Tsoga building stands as an example of a ‘green building’ that the local community is very proud of.

The following questions were not addressed at the session and we hope that someone will attempt to answer them in this forum:
Q: What has been people’s response to the concept of green living?

Q: Given that everyone refer to the need for greater density, what type of density are we talking about?