**5. Application strategies in architecture**

An essential certainty that is spreading in architecture and construction is the importance of disseminating knowledge of the long-term environmental impacts of materials, components, and technological solutions for buildings. It is now known how a design choice, in relation to materials and technological solutions and their production chain, can generate environmental impacts comparable to decades of energy consumption by a building, built without any energy-saving criteria. However, awareness-raising propaganda is still needed to make people understand how the application of the LCA methodology in architecture and the use of synthetic indicators of environmental impact must serve to optimize the life cycle of the "building system," in order to understand, from time to time and for each specific case, what are the phases on which to act to reduce environmental impacts. In the approach to the use of LCA in architecture, a complete optimization of all phases of the life cycle is not easily achievable; therefore, it is essential to define clear optimization objectives. If choices of materials and components are made by paying attention to the environmental impacts of the production and transport phase, to improve the pre-consumption phase, it is not obvious that this will lead to equally low impacts in the management and maintenance phase and at the end of life. The single strategy envisages pursuing a result with different characteristics, as well as contrasting ones, with respect to the result obtainable with a different strategy. The choice of strategy must be made in relation to the design context and the type of building, its form and function, its expected useful life. The translation of these concepts in terms of the LCA methodology consists in the definition of the objectives and boundaries of the system to be analyzed.

An important concept is that the role of the LCA environmental assessment must continue in parallel with the building design phases and not be just a final check, and it must be an operational and decision support tool with respect to the set objectives.

The types of LCA analysis that can be adopted in general are different, depending on the sectors involved or the phases considered, or the levels to be analyzed (material scale, component scale, technological subsystem scale, and building scale). The application of the LCA analysis can be done in detail in relation to the purpose and objectives of the study. The main levels of detail are:

a.**A product LCA** (defined as "simplified"), in which only the product in question is considered, not the secondary production processes, the impacts of the raw materials, fuels, and electricity used exclusively in the product line are calculated (are not considered process inputs and outputs deriving from upstream production, that of the raw material in the fundamental process); this analysis is rather simplified, and it uses generic data, both quantitative and qualitative, to make the evaluations as simple as possible. The purpose of the product LCA is to essentially provide some guidelines for the processes under investigation. Sometimes, however, the level of accuracy does not allow obtaining reliability on the results. The first objective to pursue is therefore to identify the information that can be

omitted without compromising the result. The simplification of the method is based on three stages, which are iteratively linked:


In the specificity of the LCA applied to the building and its parts, it would obviously be desirable to apply a complete or detailed level of study (c) of a building, quantifying: from the quantities of materials for the main structures and subsystems, going down in detail, up to understanding the quantities of materials for the electric cables, for the switches, for the sanitary fixtures, the pipes of the systems, and every single/small part of the product. The completeness of the application also implies considering all phases of the life cycle of the building, and for each component involved also its durability or duration and its possible end of life: all these aspects must be balanced in the LCI. For various reasons set out below, this level is not realistically usable in the building sector: information, of a design and construction nature, and the quantities relating to all parts of the building are not easily prosecutable.

In most of the cases and in the widespread practice, all the executive technical choices from the design phase are not always known, since they are often decided during the construction.

### *Life Cycle Assessment in Architecture as Decisional Tool in the Design Stage DOI: http://dx.doi.org/10.5772/intechopen.112011*

It is not the goal of the LCA application to architectural design and construction to exhaust the completeness of the data down to the smallest detail, rather than to use the potential of the methodology to compare similar solutions or contributions from different life cycle phases and understand where they are concentrated the major environmental impacts of the case considered.

The objective of the LCA applied to the building or its parts is not aimig to reach a single absolute final score, aimed at itself, but to allow for improvement judgments where an impact imbalance or, at least, awareness emerges (it often happens that in order to improve one aspect from the point of view of impacts, one is forced to accept the worsening of other aspects and, in this case, the comparison serves to understand which aspect causes less environmental damage).

In the construction sector, the utility of the comparative LCA between buildings, between subsystems, between different material, technological, and structural solutions for the same subsystem, between different components but with performances (mechanical, thermal, acoustic, fire resistance, etc.) clearly emerges at the same; from each comparison the limits and potential of each system considered emerge and, through an interpretative analysis of the LCA results, alternative solutions, or optimizations of some design aspects can be evaluated.

However, referring to the application studies of the sector available in the literature, the most widespread application sees the level of study with enlarged technology or selection (b).

For which they typically conduct:


In the sector there are studies of application of the LCA methodology to the scale of the material and the component, which can be considered with a complete level of detail (c), with the aim of building the entire production process, from the cradle to the gate, therefore from the procurement of raw materials, to industrial processes up to packaging, considering all branches of the chain of flows with the environmental impacts of machinery (and their construction), the use of the land by industry and, upstream, by industries or sourcing quarries of raw materials, etc. These assessments serve to create the process entry relating to the environmental impact for a defined unit of building material (1 kg and 1 cubic meter of material), which constitute or are comparable to the entries contained in the reference databases for the LCA. Therefore, it can be affirmed that in the evaluations of an extended technological type, at the building scale, certainly many processes are included which, taken individually, can be considered as results of complete LCA. Regarding the LCA applications that compare phases of the life cycle of the building, scientific research works emerge that specifically analyze single phases, the pre-use phase of the building

rather than the end-of-life phase of the building and components, with the objective of understanding, in one case, the production processes that have the greatest impact on the environmental impact of building construction [5–7] and, in the second case, the possible end-of-life scenarios and the advantages or limitations of each scenario (landfill, waste-to-energy, recycling, or reuse) [8–11].

The use of LCA as a methodology to support the design and optimization of production chains, in general, can be traced back to the early 1990s [12–16] and as a methodology with calculation codes that can be optimized for the building sector since 1996, at the building scale [17–25] and the scale of the material and component [26–31].

The wide use of comparative LCA in architectural design has been intensifying since 1996, with an increase in application cases, found in scientific literature, from year to year. There are now many application cases at the building scale: one trend sees the use of the methodology for assessing the environmental impact on a building, as a single-case study [32–35], which highlights the different impacts in the phases of the life cycle or the incidence of the various building systems with respect to the overall environmental and energy impact (e.g. the impact on the environmental effects of the structure or building materials respects the entire life cycle of the building [36]), as well as on several buildings compared to each other, whether they are residential buildings [37–42] or tertiary [43, 44], school [45] or public [46–48].

A widely codified use of the comparative LCA can be found at the subsystem scale, in which technologies with different materials or technological alternatives of products are compared, for example, two different structural systems are compared, steel versus wood or steel versus concrete, applied to the same building, in order to understand the most eco-efficient solution, with the same mechanical performance [49, 50]. Or, in the design phase, the comparison of the environmental impacts allows to have a complete scenario of the performances between alternative technical solutions (envelope, surface finish, facade or roofing systems, thermal insulation, roof slab, and flooring), as well as esthetic, thermal, acoustic, fire resistance, etc., also those of environmental impact [51–60]. The constant underlying the comparative applications of LCA is the functional unit U.F.: it is important to compare different products, components, systems on the basis of an equal unit of performance, in order to make the relative results comparable (e.g. U.F. equal to 1 sq.m. of envelope surface, if I compare facade systems, U.F. equal to 1 m2 of usable floor area, if we compare quantities which, in order to be compared, must be normalized with respect to a common denominator).

There are more recent application studies of the LCA to the life cycle of the building, which begin to calculate the effects of the life span of the same and the durability of its parts in the life cycle, considering the impact related to the maintenance and replacement of parties [61, 62]. Other studies focus on concepts of dynamic LCA (dynamic LCA), i.e. they evaluate the building's performance considering the temporal variations in the internal environment and the external conditions during the operational life of a building, incorporating the possibility of quickly updating the LCA results on the basis of changes to the project or on the variation of the functioning of the building (dynamic modeling scenarios) [63, 64].

Compared to the different architectural scales, there are different attitudes in the LCA application strategies regarding the consideration of all or only some of the synthetic environmental indicators: some applications adopt the strategy of simplification by carrying out an LCA evaluation which verifies only the energy consumption (indicator of Embodied Energy) and the equivalent carbon dioxide emissions

#### *Life Cycle Assessment in Architecture as Decisional Tool in the Design Stage DOI: http://dx.doi.org/10.5772/intechopen.112011*

(global warming potential indicator) [65–68], with the consequent facilitation in the immediate comparison of the results between the phases of the life cycle, as well as a dissemination of the final values more user-friendly, since energy savings and CO2eq. emissions are more commonly known and widespread concepts with respect to the environmental problems of water and soil acidification, rather than SO2eq. emissions for the depletion of the ozone layer.

Certainly, there are still advances to be pursued in the transfer of this methodology to the architecture sector, harmonizations in procedures, in order to make the results of similar studies, carried out in different research or application contexts, much more comparable. It is necessary to make designers more aware of the assessment of the environmental problems generated by the design and construction act and to make them understand how, once again, environmental issues cannot be simplified to avoid complexity or manipulated to obtain brands or labels, but they must be taken seriously and fully understood. In any case, it is understandable how it is not easy from the LCA application theory to be able to match completeness and correctness in the eco-efficiency of the solutions adopted in a building and for all phases of the life cycle. Each situation is singular and unique, linked to a physical, territorial, and social context, and it is possible to calibrate the architectural and constructive choice on this, not forgetting the verification of the environmental impacts, perhaps not for all phases of the life cycle, but adopting design and construction strategies that we have in mind the building and the possible scenarios in the different phases.
