‘Reducing the carbon footprint’ is a phrase that you might have come across in many places in recent times. This is not something that is or should be limited to environmentalists only. So, what is a carbon footprint? A carbon footprint is the total amount of greenhouse gases produced directly and indirectly to support human activities, (which could be anything from heating your house with electricity, shopping, traveling by air). This is expressed as carbon dioxide (CO2).
what is the connection between hemp, the construction industry and the building industry?
Global warming is a result of the emission of these greenhouse gases or the CO2. Building and construction is also a leading cause of CO2 release. The construction industry accounts for 39% of energy related carbon dioxide (CO2) emissions. This is according to an UN report.
Energy intensity per square metre of the global buildings sector needs to improve by an average of 30% by 2030. This will enable it to meet the global climate goals set down in the Paris Agreement.
Developing countries are some of the culprits here. Rapid growth is inefficient and it is necessary for curbs on carbon-intensive building. Lack of mandatory energy codes is also a major issue in developing countries.
Carbon dioxide has a major role to play in the construction industry.
- Carbon dioxide is used as an atmosphere for MIG/MAG welding. This is done to protect the weld puddle from oxidizing. In manufacturing casting moulds, carbon dioxide helps to impart strength and rigidity.
- Carbon dioxide is also used as a compressed gas in pressure tools used in the construction industry.
- Carbon dioxide comes in handy for the creation of dry ice pellets which can be used instead of sandblasting to remove paint from surfaces.
There are many ways to decrease carbon emissions in the construction sector. But harnessing this potential will need efficient technology and effective policy. There is poor investment in sustainable buildings and construction in many countries. The choices and behaviour of consumers also play a key role.
The Global Status Report 2018 on energy efficiency prepared by the International Energy Agency and the UN show a bleak outlook. There has been a slowdown in energy efficiency investment in buildings. Energy efficiency spending had increased by only 4 per cent in 2017. This was in contrast to the rapid growth of investment in building construction and renovations.
Cooling buildings – A challenge
The report also highlights the sharp demand for cooling systems and air conditioners. Rising income levels in developing countries and higher temperatures are seen as a driving factor for the above.
Only 2.8 billion people live in a place with average daily temperature of more than 25 degrees. Out of these, only 8 per cent have an air conditioner. This means that the biggest markets for air conditioners today are not the hottest countries on the planet. This also shows that there are ways to deliver cooling to buildings which are much more energy efficient.
How can hemp help
Hemp can be applied in building and construction. This is due to a product known as hempcrete. Hempcrete is created out of lime and hemp shivs. Hemp shivs are a waste product from hemp fibre. Hempcrete is used in the construction of walls, floors, and for roof insulation.
Hempcrete is leading the innovation in Europe, Canada and US. It is a product created from the combination of hemp hurd, lime and water. Hempcrete is more elastic than concrete and is also lighter. Therefore, it does not compromise on the structural strength and thermal properties. It is best for non-load bearing construction projects and insulation. But what about its carbon footprint?
Hempcrete absorbs CO2 from the atmosphere and retains it while releasing the oxygen. One ton of hemp fibre is capable of sequestering 1.62 tons of CO2 but that is not all. Hempcrete undergoes calcination over time and absorbs more CO2. So, for a 120 square foot wall made out of hempcrete, 2400 pounds of CO2 would be sequestered and this would leave behind 1480 pounds of CO2. These 1480 pounds of CO2 would also get offset by carbon sequestered in hemp production thus leaving the entire carbon emission negative. Additional benefits of a wall made out of hempcrete are – they are fireproof, resist mold and transmit humidity.
Hemp has natural insulating properties and great durability. This means that it is a great replacement for traditional building materials.
Hemp continues to absorb CO2 through its life cycle and it also increases the strength of the hempcrete. It is estimated that hemp and lime mixtures of this nature can lock up approximately 110 kg of CO2 per m3 of wall.
Thermoplastics come from polymer resins such as polyethylene, polypropylene, polystyrene, polycarbonate, and acrylic. These are natural materials and they can find use in creation of many day to day things such as eyeglass lenses or even a surfboard. Thus, the potential is great for replacing plastic with hemp fibre. For example, 3 tons of CO2 can be offset for one ton of thermoplastic by replacing 30% of glass with 65% hemp fibre.
It is not as if hempcrete was unknown to man. Hemp is familiar to man since atleast 8000 years ago. Hempcrete was first discovered in the 1980s in a bridge abutment from the 6th century in France. Industrial hemp cultivation has seen a resurgence in recent times. With the cultivation of hemp in Australia and USA, better times lie ahead for hempcrete and hemp.