1. Background
This report responds to a call for proposal to recommend an engineering solution to a specific problem in the built environment sector.
Cement is inarguably the most used and crucial construction resource since civilizations came into existence. Over the years, especially in recent decades, buildings are becoming bigger and taller. In the year 1998, the Petronas twin towers, the two tallest buildings at that time stood at 452m (Kazmierchak and Gramsbergen, 2005). Today, the tallest building in the world, the Burj Khalifa which stands at 828m, uses 330,000m3 of concrete(Burj Khalifa, n.d.). Rodger (2018) states that most of our concrete in the world is being used to construct buildings and that the main ingredient of concrete is cement, whose production contributes to 8% of the world’s carbon emissions, which is equivalent to 2.2 billion tons of carbon dioxide per year.
In addition, the process of producing bricks in kilns not only releases carbon into our atmosphere but also large amounts of pollutants such as sulphur dioxide and black carbon into the atmosphere. (Climate and Clean Air , n.d.). These effects are not easily reversed and will accumulate in the earth’s atmosphere much to the suffering of future generations.
The Intergovernmental Panel on Climate Change (IPCC) mentioned in their special report that it is essential to maintain global temperature within 1.5 degree celsius. A one-degree increment of global temperature can result in a drastic increase of the atmospheric temperature. According to the National Oceanic and Atmospheric Administration (NOAA) statistics, the global temperature in September 2009 was 0.62 degree celsius. Currently, the global temperature is at 0.95 degree celsius, an increment of 0.33 degree celsius. With this constant rate of increment, it will definitely affect people around the world, including Singapore.
Singapore generated 52.5 million tonnes of greenhouse gases in 2017 which contributed 0.11% of global carbon emissions, that equates to 8,000 tonnes of CO2 per capita in that year (Tan, 2019). According to Dr Muhammad Eeqmal Hassim, senior research scientist with the MSS Centre for Climate Research Singapore, the constant rise of carbon emissions around the world will lead to an increase of Singapore’s to 40 degrees celsius by 2045 (Low, 2019). Therefore, it is necessary for Singapore to reduce the amount of carbon emission.
The rising of carbon emissions from production of conventional bricks have led Bricknology to source out sustainable alternatives for brick production. Bricknology has identified mycelium brick as an alternative brick to replace conventional bricks. Mycelium brick is an environmentally friendly brick which does not require coal for its production as it is created through organic components and fungus. It is praised for its super strength, ability to withstand harsh conditions, low cost, health benefits and its eco-friendliness. In New York City, an architecture firm called “The Living” created a 40 feet tower, “Hi-Fy Tower” with mycelium bricks in 2014. David Benjamin, principal architect of The Living stated that on top of being cheaper to produce, mycelium bricks requires minimal energy for growth, in fact, it decomposes waste to grow and does not produce any waste itself; this in itself is a revolutionary technique for producing building materials (Brownstone, 2014).
The use of mycelium bricks in construction is still in its infancy stage and based on existing research, mycelium bricks shows very promising potential in sustainability and mid tier construction projects. Bricknology wishes to implement the use of mycelium bricks in the upcoming Build-to-Order (BTO) flat at Sembawang area as a pilot programme. The team have selected Sembawang as there will be more public housing in the northern region of Singapore around existing and upcoming mass rapid transport(MRT) stations, including the newly opened canberra MRT.
1.1 Current practices for public housing in Sembawang area
The team had observed that the bricks used to build the internal structure of the house in Sembawang were made up of in-situ reinforced concrete walls, precast concrete walls and masonry walls. In-situ reinforced concrete walls and mansory are made on site whereas precast concrete wall is made in the factory and assembled on the worksite.
1.2 Problem Statement
Ideally, Building Construction Authority (BCA) should authorise the use of mycelium brick for all future construction. However, BCA is not implementing the use of mycelium bricks despite its potential as a sustainable material for construction.
1.3 Purpose Statement
The purpose of this report is to convince Building & Construction Authority to adopt the idea of using mycelium bricks and initiate a pilot project in the upcoming Build-to-Order (BTO) flat at Sembawang area.
2. Proposed Solution
The team has referenced online research done for sustainable bricks has decided to propose the use of mycelium brick on the upcoming BTO flat at Sembawang area for BCA to consider.
2.1 Use mycelium bricks in place of conventional bricks
The team conducted a site visit to the upcoming BTO public housing in sembawang area. The team was told and observed that bricks used to build internal walls for the houses were mainly by concrete and clay bricks. It was further elaborated by the construction staff that in Singapore, most internal walls in buildings uses concrete or clay bricks because of its ability and cost.
The production of concrete and clay bricks involves burning fossil fuels to heat the bricks to high temperatures which produces a high amount of CO2 as a by-product. It is also noteworthy that the production of concrete and clay bricks produces a ratio of 1 tonne of bricks to about 250kg of CO2 (Rathi, 2017).
To reduce the amount of carbon emission, the team proposes the use of mycelium bricks. Mycelium is an organ belonging to fungi that plays the role of digesting and absorbing nutrients for the fungi. The current technique for growing mycelium bricks incorporates a process of decomposing organic waste materials such as agricultural waste and sawdust, allowing the mycelium to grow in a mould and drying them after to inhibit growth to retain the shape (Bonnefin, 2018).
Although growing mycelium bricks does produce CO2, the production process comes at a sustainable cost of decomposing organic waste. This is a sustainable method of growing the mycelium as the mycelium is recycling essential nutrients from the organic waste (Hebel, Javadian, Saedi, 2019). Furthermore, at the end of a building’s estimated safe habitable lifespan, the building has to be torn down with its bricks. Concrete, the main bulk of what forms a building cannot be recycled, which means that the carbon used to produce these concrete bricks can never be reused. On the contrary, mycelium brick, given the right conditions, is easily biodegradable into soil which recycles the nutrients (Critical Concrete, 2018). In comparison with producing the same number of concrete or clay bricks, mycelium bricks produces less CO2 by a large margin.
With the incorporation of mycelium bricks into the built environment, BCA would be a leader in Singapore’s sustainability, using naturally made bricks that is at the same time, biodegradable after its projected life expectancy.
3. Benefits of Proposed Solutions
The team’s proposed solutions can lead to many benefits for Singapore’s built environment sector.
3.1 Physical Capabilities
Mycelium brick is fifty six times per cubic meter lighter than your typical conventional bricks. Despite it being lighter compared to conventional bricks, mycelium bricks are stronger than conventional bricks in terms of pound-for-pound (Critical concrete, 2018). It is capable to withstand a high amount of compression force. Mycelium bricks can be grown in a controlled environment where the mycelium is grown in such a way so as to produce desired physical capabilities. In one such experiment, the results are a mycelium brick that is 200,000 times more ductile than steel, 10,000 more rigid than brick while still able to support the weight of 50 cars (Abrams, 2014). As proven from architectural structures, it is able to withstand external factors such as wind and rain.
3.2 Fire Resistance
Although mycelium does take a shorter time to ignite in comparison with clay and concrete, the beauty about mycelium bricks is that the moment the outer layer is burnt, a layer of char forms on the surface of the mycelium which actually increases the flame resistance of the entire brick itself (Jones, Bhat, Wang, John & Moinuddin, 2017). This results in the bricks actually being able to last longer in prolonged fires, maintaining its structural integrity long enough so that the building does not collapse under its own weight, leaving room for people to escape.
3.3 Good thermal insulation
Mycelium insulation has way better R-value and EPS R- value as compared to conventional insulation boards. It does not absorb heat as fast as the conventional boards (Critical Concrete, 2018). R-value is a measure of resistance to heat flow through a given thickness of material. The higher it is, the greater the resistance to heat flow. It is also thinner and lighter which makes it easier for construction process.
3.4 Environmentally friendly
Mycelium is 100% biodegradable as it is an organic compound. It does not release any toxic or volatile compounds when biologically broken down. It is a common misconception that since mycelium is an organic compound, it will therefore rot easily overtime. However, this is easily prevented by drying and coating the mycelium brick to protect it from moisture.
3.5 Health
From an article “Production of Mycelium brick”, (Kishan, Rahul, Rohan & Anshul, 2018) stated that the production of conventional bricks releases many toxic pollutants such as carbon monoxide and sulphur oxides. It was further elaborated that such pollutants causes 27% of people to pass on due to cardiovascular related diseases and pneumoconiosis. As mycelium brick uses bio-based materials, it reduces the amount of toxic pollutants being released into the atmosphere. With the decrement of toxic pollutants, it will reduce the chance of people getting diseases.
3.6 Production
The production of mycelium brick is simple and versatile. Pieces of agricultural waste materials and natural organic materials can be used to make mycelium bricks, thus reducing the use of fossil fuel required when using kiln. The reduction of fossil fuel usage will result in less CO2 emissions.
3.7 Economical
Mycelium bricks does not rely on conventional factories which uses expensive machines and materials but just a mould and waste material. This reduces overall cost of production by a huge margin. A square foot of mycelia material costs around $50 (Chitnavis,2019). It only requires more human effort to put the materials together but overall it does not cost as much as producing conventional bricks.
4. Limitations of proposed solution
4.1 Production
Mycelium takes time to grow, taking a few days to weeks to be able to use it as a component to make the bricks. External factors such as temperature and moisture affects the rate of growth of the mycelium. Due to the uncertainty in its completion, it affects the marketability as an easily accessible product.
4.2 Long term
Mycelium bricks are still in the early stages in their line of production. As a result, the full capabilities of these bricks have yet to be known. Much of its credibility is theoretical as to how long it is able to last in residential and non residential buildings. It might be the solution to replacing all conventional bricks but because mycelium bricks have only been around for about 5 years, no concrete research is available for these bricks in a 50 year lifespan. No matter how much research and claims from experts that says it will last, it will only remain as projections. The only thing we are able to fully trust is to wait until it reaches its maximum brick lifespan.
4.3 Compromised structural integrity
After the drying phase, the mycelium has to be completely dry to kill off all of the fungus to inhibit its growth. If the drying phase is not done properly, the fungus can still grow which risks the brick rotting and losing its structural integrity. If the structural integrity of the brick is at risk, it may collapse and endanger its occupants.
5. Methods & Procedures
The team came across an article stating that conventional bricks uses mainly concrete and masonry which releases harmful pollutants during the process of burning in the kiln. Therefore, the team decided to research on alternative of bricks which is environmentally friendly and found out about mycelium bricks. This section details the methods used by the team to gather information for the report.
5.1 Primary Research
The team went down to Sembawang public housing estate and conducted interviews with construction staff to find out the type of bricks they were using for construction site. As most of the construction workers were from India, they mentioned that India is a country that produce most of the conventional bricks. As one of the team members used to work as a hotel technician, he was able to observe the type of cement and bricks that they were using.
5.2 Secondary Research
The team did research through articles, government websites and newspapers for relevant information of mycelium bricks.
6. Conclusion
Climate change has been an ongoing issue in the world and urgent actions are needed to prevent it. BCA can take action through piloting the use of mycelium bricks to reduce Singapore’s demand of conventional bricks. With the reduction of demand, the supply of conventional bricks will be reduced thus leading to lesser carbon emissions.
Other than implementing the proposed solution, BCA can also explore other environmentally sustainable alternatives and try it in a pilot programme.
With BCA paving the way through promoting the use of mycelium brick, the private sector will be inspired to follow suit. Collectively, Singapore will be discouraging the use of conventional bricks and thus reducing its contribution to carbon emissions in the world.
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