FORMATO I. – R ELACIÓN DE DOCUMENTOS QUE DEBERÁN PRESENTAR LOS LICITANTES

Fink’s Step 6 was the actual review of the selected and collected literature35 _{and Step 7}

synthesising the results. Webster and Watson (2002) quote Bem36 _{saying: “Authors of}

literature reviews are at risk for producing mind-numbing lists of citations and findings that resemble a phone book – impressive case, lots of numbers, but not much plot”. The

objective of this literature review is to explore the relationship of buildings with energy over their lifespan, producing a narrative that will be more than just descriptive i.e., the aim is produce a review that will in the words of Jesson and Lacey (2006) be “original,

perceptive and analytical”.

Details of the collected literature were entered into reference management software37_,

resulting in the creation of a library of references, which was extremely usable. The review of the documents themselves comprised an iterative process of search – read – annotate – organise – summarise – analyse – synthesise. The use of the aforementioned reference management software facilitated a more effective literature review, enabling efficient reading, notetaking and organisation of documents.

3.3 The ‘life’ of a building

3.3.1 Defining a building’s life cycle

Buildings may be considered as products, albeit complex and long-life instances, and it is necessary to consider a building’s life cycle from this perspective. All products and services can be thought of as having a ‘life cycle’, however the use of this term can be ambiguous, especially when used in interdisciplinary discourse (Guinée et al., 2011). Hochschorner

35 _{Of course, it should go without saying that the literature review steps were carried out iteratively.} 36 _{Bem, DJ, (1995). Writing a Review Article for Psychological Bulletin, Psychological Bulletin Vol.}

118, No. 2, pp. 172-177

37 _{Initially the software used was Papers app [http://papersapp.com] however during the research this}

was change to Mendeley Desktop [https://www.mendeley.com] as this was increasingly the tool the author used professionally.

(2008), for example observes the differences in meaning when used in environmental and financial analyses. Differences in understandings of ‘life cycle’ have the potential to cause confusion in both the planning of a study and the communication of its results and therefore clarity is vital. This section will explore how in different contexts, different meanings may be attached to the term product ‘life cycle’, including:

Product (market) life cycle comprising the phases of a product within a market, as used in determining pricing strategies, typically presented as four phases, viz., introduction, growth, maturity and decline (Dean, 1950; Vernon, 1966). Such a market-orientated perspective may not seem particularly relevant to buildings; however, it has direct applicability to the products that go into the construction or renovation of a building. Indeed, it is particularly relevant when considering novel products developed, for example, for building energy efficiency applications. It is interesting therefore to view this market- orientated product life cycle in conjunction with the technology life cycle (shown in lighter shade) in Figure 9 below.

Figure 9: Product (market) life cycle (after Cox, 2007) overlaid with technology life cycle (after Ford & Ryan,

1981)

used in financial analyses such as ‘total cost of ownership’, ‘life cycle cost’ etc. Typically used in comparisons for determination of most (life cycle) cost-effective alternatives, these types of economic models can be extended to include societal costs, in addition to direct manufacturing and use costs (Senthil, Ong, Nee, & Tan, 2003). The relative importance of the component of the life cycle cost of course will depend on the nature of the product, its application and the processes involved at the different stages of it life (e.g., unmistakably for buildings, the length of lifespan is an important factor). Figure 10 below illustrates an example of such life cycle costs for a generic building in an area graph, where the shaded areas represent quantity of categorised costs total.

Figure 10: Illustrative building life cycle cost profile (derived from Alting, 1993; Barringer, 2003; Sherif &

Kolarik, 1981; Woodward, 1997).

Figure 11 illustrates the same costs with instances of periodic renovation – note the peaks reflecting the additional costs associated with products and construction works and the recycling and disposal of waste generated from the renovation.

Figure 11: Illustrative building life cycle cost profile including instances of periodic renovation

Product (material) life cycle comprises the physical chain comprising the flows in materials and energy associated with the provision of the product, as used in life cycle environmental analyses (see for example, Guinée et al., 2001) and shown in Figure 12 below.

Figure 12: Generic (material) product life cycle (derived from Ansems, Van Leeuwen, Guinée, & Frankl, 2005,

Each process in the life cycle results in consumption of both physical resources and energy resources and in the generation of wastes with consequential environmental impacts (Rebitzer et al., 2004).

Figure 12 above offers a generic view of a life cycle, this is presented as an introduction to the ‘physical chain’ concept of life cycle that is central to the consideration of whole life environmental impacts (such as life cycle energy consumption and GHG emissions) and consequently a variant of the concept of interest to this thesis.

The specific case of the building life cycle will be discussed in some detail later in this section see for example Figure 13 on page 69. These differences in understanding of the life cycle concepts discussed above and presented in Table 4 below have the potential to cause confusion and therefore it is vital that there is clarity as to the meaning of ‘life cycle’ both in the design and conduct of a study but also in the communication of results38.

Table 4: Different views on life cycle

Life cycle Focus Description

1. Product (market)

life cycle Focus on position in marketplace Sales-orientated perspective considering market penetration over time encompassing introduction, growth, maturity and decline 2. Product (use) life

cycle economic Focus on lifespan Economic life of building, including costs of building, maintaining, operating and ultimately demolishing the building when it is of no further use 3. Product

(material) life cycle Focus on whole life resource implications

Whole life perspective of buildings, considering flows of materials and energy, encompassing product, construction, operation and end-of-life

stages

Indeed even within studies of the same type, differences in meaning arise, for example, Gluch and Baumann (2004) note that within life cycle costing, different kinds of life cycles may be considered viz., economic, technical, physical and utility; while Guinée et al. (2011) observe that there are diverging approaches to boundary setting in life cycle environmental

38 _{In such perspectives the design is not typically of a product is not considered part of the lifecycle —}

analyses. These differences can, and do impact greatly on the results of a life cycle study, whether examining financial, environmental or other metrics.

While a range of values accrue from building energy renovation projects, the principal metrics used to measure performance relate to financial returns, energy savings and GHG emissions avoidance. Understanding value flows across the lifecycle would therefore require a combination of the second and third life cycle perspective shown above. The stages of product (material) life cycle can also be adapted to form the basis of life cycle cost estimations of a renovation – this would enable an approach to be devised using a common definition of ‘life cycle’ for consideration of costings, energy consumption and greenhouse gas implications. ISO 14040 defines life cycle as the “consecutive and interlinked stages of a product system, from raw material acquisition or generation from natural resources to final disposal” (ISO, 2006a).

3.3.2 The life stages of a building

As noted previously,

buildings are long-life complex entities, involving a combination of many different materials, components and systems, which have different replacement cycles and useful lives, and their various life cycles combine to form the building life cycle

(Bekker, 1982; Cole, 1998). This life cycle comprises various processes, which combine to

deliver, operate and decommission a building. Different authors have categorised the building life cycle into varying number of stages (M. R. Fay, 1999; Sanvido, Kumara, & Ham, 1989). This has been (relatively) recently standardised – in the European context at least – by the publication of EN 15978:2011 (CEN, 2011b), which provides for four stages, namely: Product stage i.e., raw materials supply, transport, and manufacture; Construction stage

i.e., transport and construction installation process; Use stage i.e., operation, maintenance,

repair and replacement, and refurbishment; End-of-life i.e., deconstruction, transport, waste processing, and disposal. Projecting these four stages onto the generic product life cycle illustrated on page 67, results in Figure 13 which is presented above and discussed on the following pages.

In document SERVICIO DE IMPRESIÓN DE TARJETAS INAPAM DE CARTULINA (página 63-67)