5.1.3.1. Life Cycle Assessment for Building and its materials

Life Cycle Assessment (LCA) based on ISO14040 (2006) is being increasingly adopted in architectural design and construction, as it CA enables decision-making processes, such as, evaluating and selecting environmentally-friendly products and optimizing construction processes.

Life Cycle Assessment (LCA) is a systematic approach developed through the ISO14040 standard that helps architects and builders evaluate the environmental impacts associated with buildings and their materials. By adopting LCA, decision-makers can choose environmentally friendly materials and optimize construction methods, thus promoting sustainability in the building sector.

Think of LCA like a shopping list for an eco-friendly lifestyle. Just as you might compare products based on their ingredients before purchasing, builders evaluate materials for their environmental impacts throughout their entire life—from extraction to disposal.

In addition to assessing environmental impacts, LCA also facilitates estimating life cycle costs (LCC) and conducting life cycle energy analysis (LCEA). The incorporation of LCA into the building sector supports sustainable decision-making and promotes the evaluation of environmental, economic, and energy-related aspects throughout the life cycle of buildings.

LCA plays a crucial role beyond just environmental impact; it helps estimate the total costs associated with a building's life cycle, known as Life Cycle Costs (LCC). Furthermore, it allows for analyzing energy use over the building's life span. This holistic view enables builders to make informed, sustainable choices that balance economic viability with environmental responsibility.

Imagine preparing a budget for a family vacation. You would consider not just the ticket costs but also food, accommodation, and activities. LCA does the same for buildings, assessing costs related to construction, maintenance, and energy use over the years.

It is noteworthy that energy efficiency has been a primary focus in the environmental design of buildings, with the use/operational phase playing a dominant role in the LCA of buildings, due to the high energy demand associated with building operation.

Energy efficiency is critical in building design, influencing the operational phase of a building's life—when most energy is consumed. This phase accounts for a significant portion of the building's environmental impact due to energy needed for heating, cooling, lighting, and appliances, highlighting the necessity of efficient energy use in the overall LCA process.

Consider your home’s electricity usage. The more energy-efficient your appliances and heating systems are, the more you save on bills, and the lower your carbon footprint. Similarly, energy-efficient buildings reduce operational costs and environmental impacts.

Operating energy, which includes energy for HVAC, domestic hot water, lighting, appliances, and building maintenance, is easily quantifiable and can account for up to 85% of total energy consumption and 70-90% of the environmental impact.

Operational energy refers to the energy consumed during the building's life for activities like heating (HVAC), hot water, lighting, and maintaining the building. This quantifiable energy use can represent a staggering 85% of overall energy consumption and significantly contributes to the building's environmental footprint, making it essential for environmental assessments in the LCA framework.

Think of how much energy it takes to run your air conditioning all summer long. Now multiply that by the number of systems in a large building. Lowering this energy use is like finding ways to stay cool without relying heavily on air conditioning.

However, many of these factors are beyond the control of designers, particularly during the conceptual stage, as they are spread over the decades-long lifespan of a building.

While the operational energy demand can be calculated, many factors influencing it, like occupant behavior and long-term energy needs, lie outside a designer’s control—especially during the initial stages of planning the building. These elements can change over the years, making long-term predictions difficult.

It’s like buying a car and then realizing your driving habits change over time—what seemed efficient at first might not be years later. Designing a building comes with similar uncertainties.

Therefore, the selection of appropriate materials, which is often emphasized as a directive for energy-efficient design, becomes a critical decision factor in the design process. It is recommended to consider material selection as early as possible, as it not only impacts the operational energy performance of the building but also influences the total embodied energy and potential environmental impact.

Choosing the right materials early in the design process is vital. This decision not only affects the building's operational energy efficiency but also the total embodied energy— the energy consumed throughout the material's life cycle, including extraction, production, and disposal. Hence, smart material choices lead to better energy performance.

Imagine building a wooden fence versus a metal one. The wood might require less energy to manufacture, but if it degrades faster and needs replacing, those replacement costs and energy add up. Thinking through the options can save time and energy down the road.

From a life cycle perspective, the environmental impact and energy consumption of buildings are closely linked to the choice of materials. However, there is often a lack of alignment between the service life of materials (which determines the intervals for material renewal) and the service life of buildings (the duration of the operational phase). This can result in a trade-off between material selection and building energy demand and so, requires a holistic approach (Heeren et al., 2015) that considers the effects and trade-offs.

The concept of embodied energy refers to the total energy or carbon emissions that materials contribute throughout their life cycle from production to disposal. Often, the lifespan of different materials doesn’t sync with the operational life of the building, potentially creating inefficiencies. This misalignment emphasizes the need for comprehensive planning that integrates both decisions.

Think of it like using disposable containers versus glass jars. Glass jars last longer, reducing waste over time, while disposable containers gather irresponsibly into landfills. Similarly, selecting materials should involve considering their entire life cycle impacts.

The after-use life cycle phase plays a significant role in determining the overall embodied energy of a building. LCA for the 'end of life' (EOL) evaluates the environmental impact, including the energy required for demolition, at the end of a building's service life, as this is vital for decision-making since it has the potential to substantially reduce the environmental impact of the building through effective after-use strategies, such as, disassembly, remanufacturing, biodegrade-ability and the 3R principles of reduce, reuse, and recycle.

The End of Life (EOL) phase involves analyzing the environmental impacts of a building once it's no longer in use, focusing on how materials are disposed of or recycled. Effective EOL strategies—like deconstruction instead of demolition—can significantly lessen the overall impact by allowing materials to be reused or recycled, embodying the principles of reduce, reuse, and recycle.

Consider a piece of furniture. When you’re done using it, if you throw it away, that’s waste, but if you donate it or transform it into something else, you’re extending its life. Buildings can similarly be treated at the end of their service to minimize waste.

Lupíšek, et al. (2015) innumerate the Design strategies for reduction of embodied energy and embodied carbon (Subtask 4 of Annex 57) in three steps: 1. Reduction of amount of needed materials throughout entire life cycle. 2. Substitution of traditional materials for alternatives with lower environmental impacts. 3. Reduction of construction stage impact.

Effective strategies to reduce embodied energy and carbon include minimizing the amount of material used, choosing materials with lower environmental impacts, and implementing practices that lessen environmental impacts during construction. This strategic planning ensures that sustainability is woven throughout the building process.

Think of a recipe where you intentionally cut out ingredients to create a lighter, healthier dish. Similarly, using fewer materials and selecting greener options leads to a more sustainable building without losing quality.

A large number of building materials are reusable and recyclable, such as, Wood and untreated timber, and Earthen Materials (reusable/recyclable/biodegradable); Metals, mainly Steel, Aluminium, Iron, Copper, Masonry and Bricks, and Glass and ceramic (reusable/recyclable); Asphalt and Concrete (may be crushed and recycled); and Gypsum/Drywall (recyclable, sometimes biodegradable).

Many building materials can be either reused or recycled, contributing to sustainability. These include wood, metals, and even concrete, which can be repurposed instead of being disposed of, thus lowering the overall resource demand and environmental impact.

Imagine an old bike. Instead of throwing it away, you can use its parts to create something new or repair other bikes. Similarly, building materials can often be given a second life instead of ending up in landfills.

Recycling materials can contribute greatly towards reducing impact and can be achieved by; identifying materials in existing buildings that can be salvaged and reused in new construction projects, establishing on-site recycling programs, implementing comprehensive waste management plans, participating in material exchange networks, collaborating with local recycling centers.

Recycling in construction involves several strategies, such as reusing materials from existing buildings, organizing recycling efforts on-site, and collaborating with various stakeholders to ensure proper waste management. These efforts not only reduce the environmental footprint but also encourage a circular economy in building materials.

Think about how a community might set up a swap shop, where neighbors can exchange unused items. Construction projects can adopt a similar approach by facilitating the recycling and exchange of building materials, thus reducing waste.

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