Snails Uncovered : How Do Snail Inspire the Industry?

Roofs are perhaps one of the most unappreciated things we have. It provides shelter to protect us from harsh weather conditions. Our homes, shopping complexes, schools, offices and factories all have roofs to provide protection from the harsh environment. In the recent years, roofs are more than just a shelter. While providing the necessary comfort, new designs to reduce environmental impacts and to generate electricity are a few characteristics of "green buildings" which take consideration of sustainable development when constructing a roof of a building.

Snails, just like humans do, like to hide themselves away from heat.

Shells are fountain of inspiration for shelter and protection applications. Example of animals with shells are turtles, hermit crabs, and especially snails. In this post, we investigate how snail shells inspire designers to create roofs that reduce the heat of buildings and environments. In Malaysia, the weather is hot and humid throughout the year and with the rise of climate change, higher temperatures occur and intense solar radiation only make things worse especially in urban areas with large density buildings. Urban cities especially have higher temperature densities which result in 4℃ increase in surrounding temperature as compared to rural areas. This is known as the urban heat island effect.

Figure 1: White shells of the Sphincterochila boissieri

Snails are masters of heat. The Sphincterochila boissieri snail (Figure 1) lives in the desert are only able to survive up to 50℃ even when their surrounding temperature may reach up to 65℃. By comparison, human bodies are normal at 37℃ and an increase of 1℃ in body temperature resulting in a fever of 38℃ is already a health risk. So how did the desert snail survive the heat? The answer lies in two important factors, heat reflection and intelligently manipulating and management of heat. Notice that the Sphincterochila boisseri snails have white shells to reflect radiation as up to a stunning 95% of sunlight is reflected with their shells.

To put this into perspective, if all roofs in urban areas were white as a snail's, global warming effect of 24 giga tonnes of greenhouse gas emissions will be reduced, equivalent to taking 300 million cars off the road for 20 years. NYC ℃oolRoofs, an organization in New York came about with a generous idea to gather volunteers to paint roofs with special treated white paint. To this day more than 6 million square feet (557 418.24 m²) of roof has been painted.

Figure 2: Shows the difference of temperatures of Base Case Colored roofs and White Coated roofs

Snails retract themselves to the upper part of their shells to escape from heat. And at the same time, the gap between the body of the snail and the soil below it provides a layer of air cushion insulation to greatly reduce heat intensity coming from the ground surface. As seen below, temperature of the surface can be as high as 65℃. The snails retract themselves to (b) position where temperature is just at 50℃. At (d), air cushion is produced as an insulation towards heat.

Figure 3: Illustration of Heat Flow and Reduction in a Snail Shell

Modern roofs use reflective bubble foams right under their roof tiles for the same reason as the snails did. To trap a layer of air cushion that will insulate the thermal heat from the inside of the house.

Figure 4: Foam Insulation applied to A Roof

Have you ever felt so frustrated waiting for the heat to go away from your hot leather seat after you leave your car or motorbike under the sun? Motorbike seat cover nowadays come with a new design with air cushion in mind. By elevating you by a few millimeters from the seat will ensure that you will never feel the heat even after your bike is left hours under the sun. Since this technology has been applied to motorbikes all over the world, it will be just a matter of time until our car seats are changed so.

The smart use of heat also inspired a team of students to come out with an award winning building design. (Notice that the roofs are resigned to be white to reflect more heat)

Few noble inventions of the team were as follows:

In this form the space left between the shells is where the life flows.
Different spaces with different requirements can be adjusted to the form
Semi-open spaces provide the possibility of making a micro-climate
Semi-open spaces also act as a filter for the air entering the building – better ventilation