Written on Sunday, August 19, 2007 by Gemini
A new dwelling that is ultra-portable, tough as concrete and long-lasting could be the answer to the cries of millions of refugees across the world...
When disasters such as earthquakes or tsunamis strike, aid agencies need to rapidly provide infrastructure for sheltering refugees. However, tents lack durability and have major limitations in operation. Their use is especially restricted in places with extreme weather conditions, such as Kashmir. “While starvation occurs over a period of weeks, death from exposure can occur in a single night” said the UN Co-ordinator for Afghanistan, where the useable life of some tents is under three weeks due to wind damage. There are over 35 million refugees in the world. But now, thanks to the efforts of two British engineers, there is new hope for them: A revolutionary tent-type dwelling that is ultra-portable, easy to set up, and as hard as concrete.
William Crawford and Peter Brewin, inventors of the ‘Concrete Canvas’, were drawn to the challenge of providing shelter in a humanitarian crisis and the need for a simple and robust solution.
“Throughout the design process, we aimed to retain the simplicity of the original concept. The result is a product that is both simple to use and simple to manufacture,” the duo noted in their study.
While studying at the Royal College of Art, UK, their combined expertise in design and engineering provided the scientific methodologies to develop the new material technology. This helped in realising their initial concept of using inflation to create strong and durable compressive structures.
HOW IT WORKS
Concrete canvas is a “rapidly deployable hardened shelter that requires only water and air for construction.” It can be deployed by one person without any training in under 40 minutes, and is ready to use in 12 hours.
The key to the shelter is the use of inflation to create a surface that is optimised for compressive loading. This allows thin walled concrete structures to be formed, which are both robust and lightweight.
The canvas consists of a cement impregnated fabric, dubbed concrete cloth, bonded to the outer surface of an inflatable plastic inner. It forms a hut-shaped structure with over 170 square feet of floor space. The technology can also be scaled to provide larger structures.
FOUR EASY STEPS
• Delivery: Delivered folded and sealed in a plastic sack with a dry weight of around 500kg, concrete canvas is light enough to be transported in the back of a truck or small aircraft.
• Hydration: Once in position, the sack is filled with water. The volume of the sack controls the water to cement proportions, eliminating the need for water measurement. After the cement hydrates, which takes 15 minutes, the sack is cut along its seams and unfolded, strengthening the ground sheet. It is usually deployed at dusk to avoid over-drying the cement.
• Inflation: The structure is unfolded to form the shelter's platform. It is then inflated by activating a small chemical pack. This releases a controlled volume of gas into the plastic inner and inflates the structure.
• Setting: The concrete cloth curves in the shape of the inflated inner. Twelve hours later, the structure is ready to use. Holes for doors and ventilation are left where no concrete cloth is bonded to the plastic skin, thus allowing access points to be cut from the inside.