Environmentally Conscious Engineering
Statistics that reveal the impact of construction industry on the environment state that built stock on Earth produces cca 50% of annual CO2 emissions on the Planet. This needs urgent and efficient ideas and strategies in order to achieve decrease of emissions in just couple of next decades.
When thinking about sustainable construction, we have to think about the whole building design process – from extraction of resources, design phases, production of elements, materials and products which will be mounted within the building, construction works, use of building, its end and demolition and possible recycling of the waste. All of this could be achieved through use of circularity, a framework designed to achieve exactly this goal – less or no building waste, synchronized working plan, reuse and recycling of elements after buildings’ demolition.
However, concrete as material whose production causes enormous CO2 emissions, is now being more and more replaceable with mass-timber structures, either as hybrid construction either as entirely wooden buildings. It is proved that wood emits CO2 emission less by 30% than concrete. Simple replacement of certain structural elements with wooden ones, decreases sustainable performances just within structure’s performance.
So, what makes a construction sustainable?
Among the most important criteria that make a building sustainable are:
- proper orientation of building and use of sunlight,
- compact form of building,
- good air-conditioning system that uses both natural and conditioned air flow,
- use of smart systems that automate the amount of light and air quality control,
- flexible interior space capable of accepting various tenants during its life-span.
But there are criteria that emerge from the very processes of a building’s whole life-cycle.
Materials and resources. Controlled and sustainable extraction of raw materials and other resources should provide minimal pollution and nature damage. Then, materials produced must be certified as environmentally safe, with various tests made that allow their use without possibility of pollution.
Design process. Involvement of sustainability consultants from the early phases of design provide better control and defining of goals that can be achieved within the whole project. Also, consideration of new sustainable technologies regarding rainwater treatment and energy savings should be applied. Certification frameworks such as LEED, BREEAM and others have criteria lists and requirements which should be fulfilled in order to certify a building green or sustainable.
Reuse and recycle of materials and products. The larger amount of products and materials can be reused, the more sustainable a building is. Construction product design process should treat the possibility of easy demounting and removal process. Prefabrication in mass-timber construction is one of the good examples, because it contains design process that plans production and connections design in advance. This decreases time, but also makes these elements more easily removed, reused or recycled after the building’s use period. The exception are high-rise buildings which aren’t easy to demolish without large amount of machinery and energy used.
Scale. Sustainability is achievable through all urban scales – from single building or small public space, to urban settlements. For example, buildings have their cumulative impact on the environment within urban heat island effect, which means several degrees higher temperature in urban areas than those rural and green that surround them. One of the tools already proven as possible solutions are green roofs. Soil layer presents a kind of heat insulation, while at the same time retains rainwater. Energy needs in these buildings are lower due to the presence of this ’insulation’, so the massive use of green roofs can significantly decrease the temperature in urban areas.
Accepting circular approach, as well as higher care for acceptable production systems, materials and components to the whole construction process and all its phases – from extraction of raw materials, through production of elements, use of building and its end – may bring more benefits and create innovation leading to more sustainable solutions in construction industry.