Lesson Notes By Weeks and Term v5 - Grade 12
Sustainable construction and environmental impact – Week 6 focus
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Sustainable construction and environmental impact – Week 6 focus
Download the Lessonotes Mobile South Africa app for faster lesson access on Android and iPhone.
Subject: Civil Technology
Class: Grade 12
Term: 3rd Term
Week: 6
Theme: General lesson support
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Introduction: Sustainable construction and its environmental impact are critical issues in South Africa today. Our country faces unique challenges, including water scarcity, energy poverty, and a legacy of unsustainable development practices. The construction industry plays a significant role in both contributing to and mitigating these challenges. From the sourcing of materials like cement (with its high carbon footprint) to the management of construction waste, every decision has an environmental consequence.
Furthermore, considering South Africa's socio-economic landscape, sustainable construction must also address issues of affordability and job creation.
2.1 What is Sustainable Construction? Sustainable construction is an approach to building that aims to minimize negative impacts on the environment, society, and economy throughout a building's lifecycle. It's often described as construction that meets the needs of the present without compromising the ability of future generations to meet their own needs. This involves considering all stages of a building's life, from design and material sourcing to construction, operation, maintenance, demolition, and reuse. The 'triple bottom line' of environmental, social, and economic sustainability must be considered. 2.1.1 Environmental Sustainability: Focuses on reducing the environmental footprint of construction, including minimizing pollution, conserving resources (water, energy, materials), protecting biodiversity, and mitigating climate change. 2.1.2 Social Sustainability: Considers the social impacts of construction, such as improving the health and well-being of occupants, promoting community engagement, ensuring fair labor practices, and addressing social equity issues. 2.1.3 Economic Sustainability: Focuses on creating long-term economic value, including reducing operating costs, increasing property values, supporting local economies, and creating green jobs. 2.2 Environmental Impacts of Construction Materials and Processes: Construction has a significant impact on the environment.
Consider the following: Cement Production: Cement is a major source of carbon dioxide emissions. For every ton of cement produced, roughly one ton of CO2 is released.
Steel Production: Steel manufacturing also contributes significantly to greenhouse gas emissions. Recycling steel is a much more sustainable option.
Deforestation: Using timber from unsustainable sources contributes to deforestation, habitat loss, and climate change.
Aggregate Extraction: Quarrying for sand and gravel can damage ecosystems, pollute water sources, and create noise and dust pollution.
Transportation: Transporting materials to construction sites consumes fuel and emits greenhouse gases.
Construction Waste: A significant amount of construction waste ends up in landfills, contributing to pollution and resource depletion. This includes materials like concrete, wood, plastic, and packaging.
Water Use: Construction processes, such as concrete mixing and dust suppression, require significant amounts of water, which can be a strain on water resources, especially in water-scarce regions. 2.3 Strategies for Minimizing Environmental Impact: Material Selection: Choosing materials with low embodied energy (the total energy required to extract, process, manufacture, and transport a material) is crucial. Consider using recycled materials, locally sourced materials, and renewable materials.
Examples: Recycled concrete aggregate (RCA): Using crushed concrete from demolished structures as aggregate in new concrete mixes.
Bamboo: A rapidly renewable material that can be used for flooring, walls, and structural elements.
Locally sourced stone: Reduces transportation costs and supports local economies.
Waste Management: Implementing effective waste management plans is essential. This includes reducing waste generation, reusing materials on-site, and recycling construction waste.
Example: Separating waste streams on-site (concrete, wood, metal, plastic) for recycling.
Energy Efficiency: Designing buildings with energy-efficient features, such as insulation, efficient windows, and solar panels, can significantly reduce energy consumption. Passive design strategies (orientation, shading) should be prioritized.
Water Conservation: Using water-efficient fixtures, rainwater harvesting systems, and greywater recycling systems can reduce water consumption. Drought-resistant landscaping can also help conserve water.
Green Building Certifications: Obtaining green building certifications, such as Green Star SA, can help ensure that buildings meet certain environmental standards.
Life Cycle Assessment (LCA): Conducting an LCA helps to assess the environmental impacts of a building throughout its entire lifecycle. 2.4 Green Building Certifications (Green Star SA): Green Star SA is a South African green building rating system developed by the Green Building Council South Africa (GBCSA). It provides a framework for assessing and certifying the environmental performance of buildings. It awards points across several categories, including management, indoor environmental quality, energy, transport, water, materials, and land use & ecology. Achieving a Green Star rating demonstrates a commitment to sustainable building practices and can increase a building's value and marketability. Different ratings (e.g., 4-Star, 5-Star, 6-Star) represent different levels of environmental performance.