Habitat Observatory

    Architecture without Architects - Bhunga Houses
  Traditionally designed Bhunga houses in the Kutch district of Gujarat made of compressed earth blocks are quite durable exhibiting the ingenuity of the local people in adapting to the prevalent natural conditions viz desert and earthquake. As compared to conventional burnt bricks, mud bricks consume very little energy and reduce cost as well as carbon footprint of the buildings.

The main peculiarity of the Bhunga house is its design. Generally ordinary houses are of square or rectangular shape whereas the Bhunga houses are of round shape. Bhungas are very popular due to their unique design feature. The diameter of a Bhunga house is approximately 18-24 feet with a foundation depth of 24 inches.

In the 2001 Kachchh (Gujarat) earthquake with 7.6 intensity on richter scale, very few Bhungas experienced significant damage in the epicentre region. The damage that did occur can mainly be attributed to the poor quality of construction materials used or improper maintenance of the structures. Due to its robustness against natural hazards as well as its pleasant aesthetics, this type of housing construction is also known as "Architecture without Architects".

During earthquakes, due to the circular shape of the walls of the Bhunga houses, inertia forces developed in the walls are resisted through shell action providing excellent resistance to lateral forces. In addition, the thick walls required for thermal insulation have high in-plane stiffness which provides excellent performance under lateral loads. The roofing materials are generally very light weight. Since the roof is constructed from extremely ductile materials such as bamboo and straw, the performance of these roofs is usually very robust. Even in situations where the roof collapses, its low weight ensures that the extent of injuries to occupants is very low. In several Bhungas, the roof joist is not directly supported on the cylindrical walls, but is supported by two wooden vertical posts outside the Bhunga, which further improves seismic resistance of the inertia forces generated in the roof. In some cases, reinforcing bands at lintel level and collar level have been used to provide additional strength. These bands are constructed from bamboo or from RCC. These increase the lateral load-carrying strength greatly and increase the seismic resistance of the Bhungas.

Catastrophic earthquakes often leave un-imaginable destruction to property and claim thousands of lives. Building materials and structural design play a vital role in the stability of the structures during earthquakes. The circular form, monolithic construction, small openings, lightweight conical roof and low slenderness ratio of the walls makes the Bhunga houses earthquake resistant.

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    Habla Zig Zag Kilns: Clever Trick for Cleaner Bricks
  India, Pakistan, Bangladesh and Nepal are the major brick producing countries of Asia and employ a large amount of manpower. The brick making industry in these countries is most often the industry of the very poor and the under-privileged. Most of the work is done manually using inefficient polluting kilns that have a devastating environmental impact resulting in irreparable harm to the environment and the lives of those working in them.

It is important that changes made in the brick making industry in developing countries improve the overall efficiency of the kilns. This will lead to more affordable housing, reduced poverty and provide an improved economic outcome for the community as a whole.

Habla Zig-Zag Kiln technology offers a unique, low emission burning process which substantially reduces greenhouse gas emissions. The Zigzag kiln is rectangular and typically measures about 250 ft long and 80 ft wide. It has a 55 ft high fixed chimney located on one side of the kiln. An induced draft fan located at the bottom of the chimney draws the flue gas from the kiln and discharges it into the atmosphere. The induced draft fan ensures a well-controlled airflow through the kiln. The kiln is divided into 44 to 52 chambers, separated from each other by green bricks in a way that the hot gas moves in a zigzag path through small openings. The long travel path of the bricks in a zigzag pattern and the contact of hot gas from the firing zone with bricks in the preheating zone contributes to the transfer of more heat in the preheating zone. Thus, the flue gas - rather than the fuel - heats up the bricks. In addition, the waste heat in the flue gas helps to better drying and reducing the moisture content in the bricks.

The Habla Zig-Zag Kiln comes in all sizes to suit the semi-continuous village application in rural settings as well as the large continuous brickyard output of 500,000 bricks per week, operating 365 days per year.

The Habla Zig-Zag Kiln consumes less fuel, less mechanical energy and requires far less capital outlay with almost no maintenance. The need for expensive, tall and energy wasting chimneys is eliminated. UNIDO/ILO have examined and approved the technology.

The widespread introduction of the Habla Zig-Zag Kiln technology has the potential to be a major climate friendly technology as it helps to reduce CO2 emissions from the brick industry. Introduction of the Habla Zig-Zag Kiln could reduce world emissions by over 1.20%.

From a humanitarian perspective, the Habla Zig-Zag Kiln will significantly improve the working and living conditions of the poor living in developing South Asian countries. It also offers an all year round production capability and an improved overall economic outcome for the community.

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