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A Postcard from...

East Africa
article by Reid Harvey

In Swahili, the Lingua Franca of East Africa, the word 'safari' means journey. For the past two years I have been on a safari with East African ceramists: an adventure in technology transfer. The journey started with a year in the Sudan, working with a Women in Development (WID) Project for the United Nations. It has continued with ceramists in Kenya. Several side trips to Ethiopia, Uganda and Eritrea led to ceramic opportunities and environmental issues. As the journey started, it was 47 C in the shade, a hot dry wind burned, stirring up a dust storm, called a 'haboob' in Arabic. More than once we saw bright daylight plunged into utter darkness by these haboobs. Sudan's dry season lasts 10 months without a drop of rain. With the desert here advancing at the rate of seven kilometers per year, one wonders if ceramics is viable. Enter technology transfer.

When first arriving in western Sudan, I noticed near our vocational school in El Obeid, a number of wood burning clamp kilns. But our WID project aimed at training women for extra income generation in various ceramic techniques, starting with hand building tableware. Unfortunately, lack of resources and support cut this project short. My 26 students worked for four months and acquired basic ceramic skills, but it is doubtful that any of these daughters of the desert had been able to pick up the design and marketing skills needed to continue working.

Left: The half-built, vertical tunnel kiln of the Building and Road Research Institute of Khartoum University.

On the outskirts of Khartoum, 600 million bricks are produced annually. As in much of Africa, building materials are in short supply and will be produced at any environmental cost. In an insidious crisis, countless bricks are being poorly formed, then under-fired in inefficient wood burning clamp kilns. These poor quality bricks are produced not only around Khartoum but throughout Sudan and Africa.

It was hard for me to concentrate when talking to brick makers and builders. I wanted to suggest: Try adobe, try stabilized earth blocks. But habits die hard. Consumers with a little money want their bricks fired. Formed with soft mud, they quickly lose their shape and because of this, they cannot be properly stacked in the kiln and must be piled close together. Heating is by conduction, not convection, resulting in the bricks being nearly raw. Often, when driving home, I would deliberately run over bricks that had dropped from a transport truck on to the road. My curiosity as to quality always got the same answer: the bricks would crumble to dust.

I felt that the public deserved a stronger, longer lasting product. The most appropriate solution was to provide an energy-efficient kiln and teach workers how to make a better brick. Working with Khartoum University's Building and Road Research Institute (BRRI), I adapted and built an Asian vertical tunnel kiln. The BRRI's kiln will fire the bricks made on the production line of the brick plant which they own and operate. The fuel will be carbonized agricultural-waste and is made in a similar way that charcoal is prepared from wood but, importantly, it is made from cotton stalks, sunflower stalks or bagasse. These carbonized fuels, reduced to a granular size, are dispersed among the bricks when loading the kiln from the top. Every hour the brick is lowered by one batch, using a chain pulley system.

The vertical tunnel kiln is energy efficient because incoming bricks at the top of the kiln are preheated using the waste heat of its central firing zone. Secondly, the brick stack is well insulated. This system has been a success in Asia for more than 20 years. By comparison, other types of brick kilns - the clamp, Hoffman and bull's trench kilns - waste energy in preheating both their brick and their outer insulation. Hoffman kilns are massive - looking down from the top, the firing follows a circuit around the kiln's oval shape. Clamp kilns are just a pile of bricks with an opening underneath for the fuel. Often the clamp has no permanent walls - mud is dabbed all around to help prevent leaks. The bull's trench is a hole in the ground in which fuel and brick are stacked then fired. Designed to yield a batch of 180 bricks every hour, the vertical tunnel kiln will produce nearly 1.5 million bricks annually. It is fired continuously for 11 months of the year, allowing for a month of maintenance. When production greater than 1.5 million is needed, more kilns can be built. The total cost of the BRRI's vertical tunnel kiln is about US$3000. Ironically, this cost is so low that many aid donors will not consider funding it, nor will many banks lend money.

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