The emissions of vehicles earn the bulk of press involving emissions. The vast majority of vehicles list their EPA estimated miles per gallon ratings. Recently auto manufacturers received criticism for their contribution of CO2 emissions. Another large source of emissions arrives from the building and remodeling industries. Many conventional construction materials expel emissions during manufacturing, installation, staining or painting. This rating is termed the gray emissions rating.
According to a study by MIT, building construction accounts for over half of the carbon emissions in the entire world! A study at MIT (https://architecture.mit.edu/sites/architecture.mit.edu/files/attachments/lecture/Reduce%20CO2%20from%20buildings_SustCitiesSoc.pdf) estimates a house in Germany possessed a gray energy level which could power the building for 25 years. The use of lightweight materials and reduction of intensive CO2 emission materials is a hurtle the building industry must collectively clear. There is a great deal of improvement required for the benefit of stabilizing the construction and design industries towards future climate and/or government challenges.
Low Emission Building Materials
A great way to reduce the impact of emission is the use of biomaterials. A green start-up, BioMason, based in North Carolina, tackled the challenge relating to the development of environmentally friendly and cost effective brick construction. BioMason developed technology to build bricks without heat or clay. According to an EPA study, 8% of global carbon emissions are from brick manufacturing. The bricks BioMason develops emit zero carbon emissions and reuses the required water needed to make the bricks.
Traditionally, bricks require clay in a mold heated in a kiln of over 2,000 Degrees Fahrenheit for a period of several days. The entire process releases large amounts of carbon into the air, let alone the energy required to heat a kiln for several days continuously. BioMason, as their name implies, instead uses biochemistry for the construction of their bricks. The process mimics the building of corals as they are able to build expansive structures able to withstand saltwater erosion and current forces. To make the Biobricks, a mixture of sand fills a rectangular brick mold. Works then inoculate the mold with bacteria, which wrap themselves around the grains of sand. The bacteria-encircled sand attracts calcium carbonate. Nutrient rich water irrigates the brick molds allowing the crystals to expand. Once the crystals grow and fill the gaps, the mixture develops enough rigidity in four or five days for use. The bricks are rated to perform as well as sandstone in strength tests.
The use of lightweight materials reduces the associated emissions with production and transportation of heavier traditional materials. One great new product is concrete with expanded aggregates. This concrete manages to achieve a lighter weight and superior insulation to conventional concrete. Allowing the elimination of an entire layer of new materials in the form of insulation shows a primary benefit.
Low Emission Finishing Materials (Low-VOC)
The use of low emission materials is a great step in the sustainability and ecofriendly direction, but the materials still need to receive finish, paint and staining. This section is robust and developed and there are several options for eco-friendly paints, stains and finishes. All the chemical binders and application aids are all recent inventions. Archaeological evidence shows ancient structures were painted and stained long before the manufacturing of latex and other modern petrol-derived chemicals called volatile organic compounds (VOCs). The rise of VOCs in paints owes to unique capabilities of evaporation of the compounds once exposed to air to leave only the pigment behind. An ancient method of paint application is milk paint. This form of paint uses a milk protein casein, a major ingredient in cheese, to bind pigments to the application surface. Milk paint comes in a rich heritage color palette, conjuring images of a brick red barn with natural and unique variations. Currently VOCs are scrutinized by their effect on indoor air quality. The use of Low-VOCs earns credits from LEED certification audits.
LEED Certification and Low-VOC
LEED certification pertaining to VOC lists seven different categories for interior and exterior features to achieve compliance. These categories include;
- Interior paints
- Interior adhesives and sealants
- Composite wood
- Ceilings, walls, thermal and acoustic insulation
School and healthcare certification has an additional category, external applied products.
The interior paints, adhesives, sealants and furniture all must reach a threshold of 90% low-VOC to achieve credit. Achieving credit for the use of low-VOC materials ensures a good step in the right direction and is an important consideration for the design and building of structures. Earning credit for the use of low emission materials according to LEED targets the effects on air quality. This opens the door for the use of intensive carbon emission materials. A well designed building will use lightweight materials, which are easily recoverable or reused upon the end of the building’s life. There is a marvelous opportunity to vastly reduce the emission associated with the building industry. A careful eye of design with considerations of the stream of construction materials ensures a bright future for reducing the large emissions associated with construction.