The Comprehensive Guide to Life Cycle Assessment (LCA) of Buildings
The modern construction world is transitioning towards sustainable methodologies. At the forefront of this evolution is the Life Cycle Assessment (LCA) of buildings. Adhering to standardized procedures not only advances consistency in assessment but also facilitates benchmarking, a cornerstone of progressive architectural and engineering practices. This guide revolves around the LCA model rooted in the structure specified by CEN TC 350 for construction work sustainability.
Foundations of the Life Cycle Assessment Model
The underpinnings of our proposed model are two pivotal standards:
- EN 15804 : This standard addresses the product-level assessment.
- EN 15978 : This zeroes in on the building-level assessment.
Choosing a standardized methodology is crucial for:
- Maintaining a uniform approach tailored for construction work evaluation.
- Ensuring comparability among different building evaluations.
- Upholding the key objective of benchmarking.
A Deep Dive into the Model’s Specifics
The intent is to furnish details on our adopted model, especially regarding sustainable design and its application in the LCA of buildings.
Basic Requisites for Conducting Analysis
When delving into the LCA, certain parameters and assumptions form the bedrock of calculations. This guide illuminates these requirements and illustrates any model variations from the referenced standards.
Any element or specific not covered herein should be sought from EN 15804 and/or EN 15978.
Integration with Professional LCA Software
Our model is seamlessly integrated into leading LCA software, ensuring that professionals have the tools they need for meticulous building assessments. The subsequent sections will elucidate on this software implementation.
The Model’s Expanse and Depth
Although our model can serve the LCA of an entire building, our benchmarking primarily concerns the building’s structural system. Therefore, subsequent discussions will cater to this essential component.
4.1 Objectives and Limits of the Analysis
4.1.1 Primary Aims
The LCA’s crux is to evaluate the environmental footprint of a building’s structural system over its entire lifecycle, from material inception to its ultimate end. The overarching ambition is the creation of a uniform LCA tool, pivotal for benchmarking residential and office structures.
4.1.2 Defining Functional Equivalence
Here, functional equivalence encompasses:
- Building’s purpose (residential or office).
- Total Gross Floor Area (GFA).
- A defined time span.
For office spaces, an alternative functional equivalent considers the number of workstations over the GFA. The results are normalized based on the building’s GFA and year.
A significant component is the estimated building lifespan, rooted in the design code or structural system regulations. In the absence of explicit lifespan documentation, a 50-year period is the norm, aligning with EN1990  for residential and office structures.
4.1.3 Boundaries of LCA
Every phase, from product inception to the end-of-life stage, is encapsulated in the model. The modular concept, introduced by CEN TC350 standards, demarcates the LCA’s system boundaries. A notable exception is Modules B6 and B7, focusing on operational energy and water consumption during a building’s lifecycle. Since these do not influence the building’s structural framework, they are omitted.
Furthermore, to align with the model’s objectives and bolster EU resource efficiency directives, Module D finds its place in our building’s LCA. This is a divergence from the conventional CEN TC 350 standards, which view Module D as an optional inclusion.
Table 1. Scope of the LCA
|Product stage||Process stage||Use stage||End-of-life stage|
|A1 A2 A3 A4||A4||B1 B2 B3 B4 B5 B6 B7||C1 C2 C3 C4 D|
|Raw material supply||Transport||Manufacturing||Transport|