Category Archives: Green Buildings

Deliberations of the Panel Discussion on Sustainability in Architecture in Nigeria

The built environment is responsible for the largest consumption of energy produced in the world. They have a corresponding largest global greenhouse gas emission by sector, 40% according to the United Nations Environment Programme (UNEP). How does this all affect us and the environment? Negative impacts of climate change have positioned many people in danger. It has destroyed lives and properties. Worse, it places a dark cloud for future generations. As such, there is need to reduce the impact of our built environment on the carbon footprint.

The French Institute of Nigeria and Green Habitat Initiative, on 31st of May in Abuja, brought together professionals in the built environment industry to debate the right sustainability principles and materials for Nigeria’s built environment. Four panelists drawn from different disciplines and professions that cut across sustainability in architecture were brought together to lead the discussion. After introductory speeches by the panelists, a panel discussion held between the panelists, moderated by the Director of Green Habitat Initiative Sadiq Gulma.

A summary of the viewpoints of the four panelists is highlighted below.

Nmadili Okwumabua is Nigerian and promotes modernizing African architecture in Nigeria’s cities, through her organization Community Planning and Design Initiative. Through her presentation and contributions to the discussion, she stressed the need to reclaim our heritage by not being embarrassed about using red earth for our buildings in Abuja. Through her organization, Nmadili receives entries of architectural plans modernized with African values from everyone around the globe. She has received many great entries reflecting numerous African culture and values in their design. The panelist revealed she is currently building a prototype of such sustainable houses. The model would be instrumental in advancing the movement.

Having expressed her pessimism at the beginning of her presentation, Armelle Choplin our second panelist has been following cement, what she calls ‘the grey gold’ from Nigeria through Benin, Togo to Ghana. She is concerned that Nigeria may not stop using cement in building because it is becoming cheaper and Dangote Industries is providing all the cement Nigeria needs. Through her research, she has discovered there is a social symbol and even political to the use of cement in our buildings. People who use other materials, such as red earth maybe seen as less privileged. There is a challenge of finding skilled local builders to teach foremen how to use red mud in constructing strong buildings that can go as high as 10 story building. For a paradigm shift to take place, she asserts that notable and prominent people and organizations like Dangote would play an influential role if they take the lead.

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Having understood the local issues with the building materials in question, Mr. Stephanne Pouffary was on the panel to provide the macro vision of sustainability in cities. Through his NGO, ENERGIES 2050 he has worked with up to 30 cities all over the world including those in West Africa to help them advance their energy efficiency and sustainability goals. His contribution clarified that different cities have different priorities and motivation to go green. Our ability to personalize the codes that will drive everyone to cleaner cities. For that to work, he highlighted 3 things that needs to be done; increase professionals’ capacity in sustainability, form regional coalitions to promote goals and work out the cost benefit analysis for sustainability to go mainstream. At the end, cost drives everything.

All the talk would be in vain if there are no institutionalized policies to control and regulate the built environment. The fourth panelist, Dr. Sherif Y. Razak who is from the Department of Development Control (authority in charge of approving all building plans and development in Abuja) was on the panel to describe what the government is doing and needs to do. Currently, the Department has instituted a green building committee to vet all building submissions against certain green building concepts. However, a lot needs to be done before a bigger impact can be made. He stressed the need to increase capacity amongst professionals, including government staff. A prototype of buildings with such sustainability standards would be pivotal in influencing building policy and regulations. Therefore, what Ms Nmadili is building should serve as a good reference point for policy makers to use in changing the regulations.

After debating amongst each other, the panelists engaged with the teeming audience. Many shared their views and supported the fact that capacity needs to increase, especially amongst architects who are the chief drivers of the built environment. Many others questioned the officer from the Department of Development Control and their need to enforce the principles.

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The event concluded with more discussions amongst participants during the cocktail.

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How We Are Making Abuja Hotter

If you have been into a conversation with others or overheard people saying Abuja is so hot, here are the best reasons why it is so. We may all think heat and its presence is caused by nature, the sun or the hot dry winds of the Sahara Desert. But they aren’t the only reasons why.

The biggest heat source, the sun, emits as much heat as it wants to, but other factors limit how much of this heat gets into our cities, how much is retained and how much is emitted back or outside the city.

Whenever each of us builds a house, he or she increases the amount of heat in that area and generally, the city. Whenever the city councils builds a road, a percentage of heat will be added in your city. It’s a straightforward heat budget, the more concrete buildings,  asphaltic roads and developments we have in the city, the more heat that will be present in our city, especially at night.

Urban heat island (UHI), is a phenomenon in which urban areas have higher temperatures than nearby rural areas, due to human reasons. The phenomenon has been discovered about 50 years ago and is known to affect so many cities’ energy consumption, thermal comfort, air conditioning costs and human health . The more a city develops (puts up more buildings), the more heat island it builds.

I came to know about this phenomenon as a graduate student. My MSc thesis had chiefly investigated how to make our buildings cooler by using living green roofs (they inevitably cool the cities too). UHI is present in many cities in the world, albeit unwanted. Many cities are doing whatever they can to combat this effect. One major way is increase in vegetation; trees, green roofs, high albedo materials (materials with high solar reflectivity), water bodies and fountains, etc. So if we want to mitigate UHI, we need to combat it by growing vegetation.

What about Abuja?

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Let’s understand a little of the geography of Abuja. At an elevation above sea level of 864m, the capital of Nigeria sits higher than many Nigerian cities. The climate is a tropical savannah, with above average temperatures of 25 degrees Celsius, rocky terrain and a rainfall season that lasts for only 5 months. There are many hills around the city. About 4 million people live in the city during the day time, with only a quarter of a million estimated to be living in city at night. It’s like the Bay area in the US. Owning to high costs of apartments and rents, many people who work in the city during the day time travel for 20 to 50 kilometres to their homes in nearby areas.

These nearby areas aren’t flooded with all the cars, concrete and asphalt of Abuja. As I earlier mentioned, concrete and asphalt are the major reasons why we have UHI.

How?

Those materials and many others developers put, behave like heat sinks. During daytime, they absorb heat from the sun. When the night comes, instead of the city to be cooler, it is hot because the heat sinks emit this heat back in to the environment. As soon as the heating source disappears (they stop absorbing heat), they start re-emitting heat back.

If you really want to experience this, you should take a walk in your neighbourhood at night. You will feel the night is still warm, instead of it to be cool like the neighbouring rural areas with less built up areas. Placing your face very close to the road or interlocking blocks,  you will most likely feel a hotter air around that region than when standing. This heat, summed up from all heat sinks in the city, causes the UHI.

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Temperature profile of built up areas ompare with rural and suburban areas (credits: Wikimedia Commons)

So when you want to build tomorrow, ask your building engineer and architect to use non-heat sinks on your site. Don’t do interlocking blocks around your house, put grasses. Green vegetation, owning to their nature, do evapotranspiration. Evaporated water cools the microclimate around the house and ultimately, the city. It improves the thermal conditions of the city.

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Mitigating UHI in Abuja

Its sad when you drive in to so many estates in Abuja with little or no vegetation at all. The urban planning and building policies have inevitably increased UHI. The policies must change to push for developers to start using high albedo materials. I blogged about the plans of enforcing green building strategies in Abuja by the development control here. But we do not only need green building regulations,  we need city wide green regulations. More trees, more green areas, less concrete, less asphalt, more use of natural ventilation, more water bodies, etc. Building policies remain the biggest way to effect a big change on reducing the UHI present in our cities. As clients, developers and designers, we can equally be motivated by the need to make our city greener through the various ways we act.

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More green areas around buildings ensures cooler microclimate (source: tolet.com.ng)

Cooler cities meant cooler environments to live, less heat, less energy consumption, more energy costs savings, better health and thermal conditions etc. etc.

Has this piece broadened your horizon of how cities become hotter than rural areas? Do you wish to build a house or an estate and want to make it as green as possible? Why not get in contact with me.

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What is a Green Building?

Whenever I mention the word ‘green building’ to many people who are outside the professional realm of green building and sustainable construction, the reaction and responses I receive for what they understand is a green building are often divergent. The two most conceived meanings of a green building are either a greenhouse (for farming) or a house powered by renewable energy, which is not a very wrong answer but it is not entirely correct as it leaves other major aspects of a building uncared for, environmentally speaking. There is a third simple response though, a normal house painted in green colour.

A green building encompasses much more than these responses. In the widest of definitions, it is any building built with numerous eco-friendly strategies. It is one that is resource efficient, does less harm to the environment and consumes less energy (energy-efficient). Simply powering your home with solar panels in the strictest of definition does not qualify a building to be a green building. Although it has satisfied a major aspect of what makes many buildings unfriendly to the environment and climate, other aspects such as the site it was built, how water is used in the building, materials used in the construction and a host of other things also need to be environmentally assessed.

A green building is one that employs environment friendly strategies from the planning, design, construction, usage, renovation and deconstruction.

A number of countries like the US, UK, South Africa, Japan, Australia etc. have developed green building rating systems to certify whether a building is green or not, based on achieving a number of points that accrue based on how eco-friendly it is. For the most part what is assessed in every building to say whether it is green or not, the following are normally checked.

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Aspects of green building (source: pabuilders.org)

Site Selection and Analysis

The choice where to put up your house, prevailing climatic and micro-climatic conditions, site topography and presence of vegetation helps to guide builders in achieving the status of the green. In Abuja, the city I live, years back, developers where converting green areas (sites planned to be used as green parks) to residential and commercial purposes. Some others convert arable and Greenfield sites. These choices are detested when aiming to design green. The urban ecology should not be harmed or disturbed to that extent.

The direction of the sun should be taken in to consideration. Understanding where the sun passes throughout the year will reveal valuable information of solar heat gain into the house, use of daylighting and shading of buildings (including neighbouring buildings). Many of these are better understood by architects and engineers. But the major take away from this is, for buildings in temperate regions like Nigeria, we do not want heat into the buildings, so designers must at all cost orient the building to keep the sun out, while maximizing its rays for daylight.

Wind conditions, speed and direction, must be known in order to design for optimum natural ventilation. In essence, wind conditions and sun path are used in order to maximize the merits of the existing micro-climate.

Site Plan

This is different from what the site analysis does, but it incorporates the results of the analysis in choosing a proper building orientation, building position, building carbon footprint and drainage.

Buildings in temperate regions should be oriented in the east-west axis. Where the building has major facades should not be directly receiving the sunlight, but the wind.

Building Design

When site conditions are fully understood, the design of the building should reflect the results. Use of natural ventilation and natural lighting should be maximized. Size of facades should be made big in case of temperate places like Nigeria, to allow for more of this natural ventilation and let in more sunlight.

Material selection has huge implications on how green a building is. A green building will consider a life cycle assessment of materials used. From extraction, production to transportation. Using locally available building materials is highly desirable in order to reduce transportation cost and pollution and also supporting local economy. Material composition will also affect energy consumption of the building. Some materials like stones and concrete store a lot of heat and thus heat the building in the night. Wood on the other-hand does not. The choice of the materials will depend on the existing microclimate.

Resource Use; Energy, water, waste

A green building may be defined as a resource efficient building. How it uses water, energy, generate and dispose waste says a lot about how green a building is. For energy, use of renewable sources for power supply is important. Electrical appliances that consume less energy like LED bulbs are more desirable. LEED, which is a green building rating systems, assigns the most points for the energy consumption of buildings.

Water is another vital resource that needs careful management to show that a building is environment friendly. Water efficient buildings have low usage of water, recycles waste water and even collect rainwater from their roof.

The last major resource to consider in managing is waste that is going to be generated. Waste water treating and recycling as discussed in water efficiency above is a major part of it. Solid waste is a major thing to consider. For most green buildings, sorting of wastes and composting are the major solutions. Waste is sorted into perishables (food), paper, plastic (PET), glass and metal etc. mostly sorting is based on the waste management of the city. For some cities not practicing this, a good way a green building can take care of its solid waste is to compost it.

These enumerations and major features form a big chunk of designing a green building. Any green building should address these highlighted issues, although a number of other features exist that need to be addressed by the green building designers.

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