Let’s ‘green’ our buildings

instance, buildings at the corner of Nelson Mandela Avenue and Julius Nyerere Way have glass facades which may appeal to the eye but if you take the menacing heat that these glasses are radiating into the environment, the picture changes.
Pedestrians have untold stories of the heat wave that they have encountered any time they choose to come close to these buildings on a hot summer day.
If trees and cars could talk, they would have complained similarly. Green building, a concept in sustainable development, which seeks to enhance energy and resource efficiency and reduce environmental impact of buildings, was obviously ignored during the construction of the Julius Nyerere Way/Nelson Mandela Avenue structures and several others in Harare and across Zimbabwe.
Even for recent properties in Harare, environmental considerations are still ignored. But the concept of green building cannot always continue to be rescued from the dustbin.
It is a critical concern area in the fight against climate change and global warming. The International Atomic Energy Agency recently estimated existing buildings are responsible for more than 40 percent of the world’s cumulative primary energy consumption and for about 25 percent of global carbon dioxide emissions.
These statistics are saddening for those concerned about climate change. Everyone should be concerned and the current construction pattern in Zimbabwe does not show this.
But what is a green building and how does the lack of it affect human health and the environment?
Obviously, those people scorched by the heat emanating from the afore-mentioned buildings above can clearly define the impact of buildings insensitive to the environment.
Building green is driven mostly by environmental, economic and social benefits.
A green building “is primarily an energy and resource efficient construction which is also environmentally responsible” in terms of its design, construction, day-to-day operations and even demolition.
Building materials and other products, wherever possible, should be made from recycled materials and manufactured renewable resources.
Urban environmental planning expert and past president of the Zimbabwe Institute of Regional and Urban Planners Mr Percy Toriro describes green building as sustainable building.
He says: “It is about building structures that use locally available materials thereby reducing the carbon footprint of buildings.
“It is also about being sensitive to environmental issues such as climate change when building.
“Elements that also make a building green are use of renewable materials as opposed to non-renewable materials, use of solar energy, and use of non-polluting materials. In doing so, the building does not significantly contribute to climate change and global warming.”
Indeed, studies have shown that sustainably designed buildings cost less to operate and have excellent energy performance, according to a 2009 report by the US General Services and Administration.
It is also generally agreed that occupants within the overall green structure are more satisfied and productive than those in typical commercial buildings.
Mr Toriro says the choice of materials in a green building is critical. In tropical countries like Zimbabwe, the use of glass and any other such reflect materials when constructing must be limited.
Green building designs should optimise on use of natural lighting and ventilation.
A green structure is a building designed to accommodate passages that have sufficient daylight to avoid the use of electrical energy. It is one that has adequate openings to allow natural ventilation.
“In extreme weather conditions, it can be used without mechanical air-conditioning and still be comfortable to live in,” says Mr Toriro.
The bulk of high-rise buildings in Zimbabwe, however, are not built to satisfy the environment.
However, the importance of an elaborate consideration of the environment cannot be over-emphasised.
There is need to preserve ecological systems against actions in appropriate land use planning.
Green building technologies should also consider water efficiency, waste and toxic reduction as well as using plants and trees through green roots and rain garden techniques for reduction of rainwater run-off.
Although the concept of green building is still very poor in Zimbabwe, the country is a pioneer in the use of green building technologies.
Wikipedia has described Eastgate Mall in central Harare as “probably the first building in the world to use natural cooling to this level of sophistication”.
The concept of sustainable design was also used exclusively in the construction of Batanai Gardens, Hurudza House and Chinhoyi Provincial Hospital, all structures having been designed by world-renowned Zimbabwean architect Mick Pearce. All these structures use bricks extensively, incorporate lots of plants in the design and use lots of lighting.
In the mid-1990s Eastgate scooped an international award as the most eco-friendly designed building in the world.
The building makes extensive use of natural air-conditioning “that is allowed by the chimneys one sees on top of the building that act to regulate temperature in the same manner a molehill does.”
The translucent roof allows natural lighting in the mall. The design at Eastgate ensures complete natural ventilation and cooling, using only 10 percent of the energy required by a similar conventionally cooled building.
This process is called passive cooling and avoids the use of large-scale air-conditioning that often cause air pollution in the structure.
In the first five years of operations the East- gate building saved US$3,5 million in energy cost.
As explained by Wikipedia, passive cooling is when the building absorbs heat at daytime before releasing it at night as temperatures fall.
The Eastgate concept has also been borrowed to construct and develop London’s Portcullis House that is close to the British monarchy’s Westminster Palace.
So why is there still poor appreciation of the green building movement in Zimbabwe?
Mr Toriro reckons that there’s still “too much obsession with designing typical Western buildings in a much hotter climate.
“In terms of materials, there is too much use of imported and exotic finishes that reflect a lot of light.”
What needs to be done to increase sensitivity to green buildings?
“The way forward is to start by raising awareness on the advantages of green buildings. Secondly we need a regulatory framework that encourages green building designs and offers incentives for them.
“Lastly we wish to put legislation that compels all buildings to be green. This may include taking measures on existing buildings to make them green with minor innovations,” he advised.
These days we sit on the edge of our chairs in conference rooms talking eloquently about the weather politics, economics and again the weather, how hot or cold it is.
As responsible custodians of the earth, society must seriously start to take action in the manner in which natural resources are used.
If green building can conserve energy, then the construction sector must implement it in full even in the absence of a binding legal framework compelling them to do so.
God is faithful. Let’s share the climate story.
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