Summary Reader's Response Draft 4 - Post-graded Revisions
IMPORTANCE OF CONDUCTING LIFECYCLE ASSESSMENT (LCA) ON GREEN BUILDING MATERIALS
In California’s Department of Resources
Recycling and Recovery (CalRecycle)'s article, Green Building Materials (n.d.), it is
stated that using green building materials encourages the conservation of
waning non-renewable resources globally, reduces building owners' and
occupants' costs throughout the building's lifecycle, helps conserve energy,
improves occupant productivity and health, and provides enhanced design
flexibility. Early design selections and establishing strategies are essential
for green building materials (Froeschle, 1999). The Lifecycle Assessment
(LCA) is a multifaceted system of qualifying and comparing inflows of
materials, energy usage, and emission outputs with regard to building materials
at varying spatial scales and contexts (Finnveden et al., 2009, as cited in
Ding, 2014). However, due to data limitations, LCA has constraints in
evaluating green building materials (Finnveden et al., 2009). The environmental
assessment of materials and buildings is convoluted due to its subjectivity and
complexity (Saghafi & Teshnizi, 2011). A building’s materials influence its overall performance, and the materials' impacts should be considered
"from cradle to grave" (Song & Zhang, 2018, p. 2).
Given the criticality of green building materials for sustainability, it is imperative to use LCA to have a full lifecycle outlook toward selecting green building materials to holistically determine responsible material usage, energy consumption, and building emissions.
Materials used are essential contributors to a building’s lifecycle impact. Buildings impact the environment throughout their lifecycle, and the building materials used will affect their overall performance (Bribian et al., 2010). Sustainable building materials are often perceived to consist of naturally-occurring materials. Nevertheless, such materials are not necessarily green. Asbestos, once added to some building materials, is now banned due to its carcinogenic properties; radon, a radioactive gas emitted by some stones in buildings, can be harmful to inhale; and turpentine, a solvent obtained by distilling tree resins, can negatively impact human health (Franzoni, 2011). Thus, it is crucial for building stakeholders to understand and conduct thorough LCA of the building materials to be used. This allows them to eliminate building materials with qualities that are detrimental to the environment.
Energy consumption and carbon
emissions are other critical considerations for green building materials.
Buildings use 30 – 40% of all primary energy globally,
and they are responsible for 40 – 50% of greenhouse gas emissions (Asif,
Muneer, & Kelley, 2007). Through lifecycle analysis, operational energy
demonstrates a major share (80–90%) in the lifecycle energy usage of buildings,
followed by embodied energy (10–20%) and demolition and other processes
(>1%) (Ramesha, Prakasha & Shukla, 2010). The LCA of corporate buildings
constructed in China using steel and concrete depicts embodied energy and
environmental emissions of steel-framed buildings to be lower than
concrete-framed buildings (Xing, Xu & Jun, 2008). Nevertheless, due to the
higher thermal conductivity of steel compared to concrete, operational energy
consumption and greenhouse gas emissions were larger for steel-framed buildings.
Hence, their overall lifecycle energy consumption and carbon footprint were
slightly higher. LCA of a building’s energy consumption and carbon
emissions is vital to accessing strategies to reduce them. When applying LCA,
the segments of a building’s lifecycle with higher energy demands and carbon
emissions can be identified and addressed.
Due to data limitations, LCA tools are inadequate in verifying certain environmental impacts throughout a building’s lifecycle (Cole, 2010, as cited in Ding, 2014). These limitations include data variability, incomplete or erroneous data, lack of precision, and inaccurately or wrongly implemented digital algorithms (Finnveden et al., 2009). LCA does not adequately address how well a product or building material can be recycled (Saghafi & Teshnizi, 2011). The effects of recycling are handled through allocation, which creates flaws in accuracy based on assumptions of a material’s future recyclability. A theoretical example of ore-based steel beams, which can be considered a green building material due to their recyclability, illustrates this (Thormark, 2001). With available LCA allocation methods, varying assessment impacts can range from the dismantling, and upgrading of transportation processes associated with recycling steel to all impacts from ore-based steel production, future waste treatments, and associated transport emissions. The lack of predictive data and arbitrary assessment produced when utilising LCA for recycling may give building stakeholders an impression of being descriptive rather than being based on assumptions of the future (Thormark, 2001). This demonstrates how data limitations could cause uncertainty when using LCA to determine the impacts of green building materials.
Despite their limitations, LCA methodologies have been
cultivated over the last decades (Finnveden et al., 2009). Current developments
in databases, quality assurance, consistency, and harmonisation of methods
contribute to this. With growing comprehension and interest in developing LCA
methodologies, more innovative research and solutions can be conducted. Greater
accuracy and precision in analysing building material impacts, especially green
building materials, would allow for enhanced holistic considerations of building
emissions, energy consumption, and usage of materials.
The examples above demonstrate that the longstanding effects of using green building materials may result in an overall disservice to the environment despite their immediate or perceived benefits. Building stakeholders must be able to discern the overarching impacts of their materials and buildings throughout their lifecycles. This is attainable through the application of LCA, where the lifecycle impacts of materials are thoroughly and holistically analysed. Green building materials can be acutely selected and used responsibly to provide enduring environmental benefits such as reduced building and carbon emissions and decreased energy consumption.
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Asif, M., Muneer, T. & Kelley, R. (2007). Life cycle
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potential. Building and Environment, 46(5), 1133-1140.
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California’s Department of Resources Recycling and Recovery
(CalRecycle). (n.d.). Green building materials.
https://calrecycle.ca.gov/greenbuilding/materials/
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I appreciate this revision of a very fine essay.
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