Methodology of LCA

A life cycle assessment (LCA) consists of four independent elements (ISO [1-4] CML [5])  

The life cycle inventory analysis involves data collection and calculation procedures to quantify the total system s inputs and outputs that are relevant from an environmental point of view, i.e., mainly resource use, atmospheric emissions, aqueous emissions, solid waste and land use. 

The life cycle interpretation is the final step of the LCA where conclusions are drawn from both the life cycle inventory analysis and the life cycle impact assessment or, in the case of life cycle inventory studies, from the inventory analysis only. As an outcome of the interpretation stage, recommendations can be formulated which, for example, may be directed to producers or policy makers. 

The main objective of this chapter is to review full-sized LCA. Howevei a few more studies were taken into account that are much more limited in scope, e.g., by carrying out an assessment only for non-renewable energy and CO2 emissions. It was felt that these studies nevertheless contribute to a better understanding of the environmental aspects because they address materials that have not been studied from this angle so far or because they provide an indication about how certain or uncertain the results are. 

---

Before examining the approaches to recycling textiles, it is important to place this discussion in the context of the product life cycle. The methodology of LCA is one approach to quantitatively assess the environmental advantages of recycling fibre. An LCA typically considers the energy, water and chemical impacts of a product system from cradle (raw materials) through to production, distribution, use by the consumer and disposal. Formal LCA follows ISO 14040 and ISO 14044 standards. It requires determination of the functional unit of the product or raw material in question to be assessed, for example T kg of cotton fibre , or one viscose blouse . Importantly, LCA is conducted under defined system boundaries. For example, the LCA may be... 

Greenhouse gas emissions for biomass derived bio-based Broad range, but more or less on the same level Very low, because of the methodology of LCA... 

Detailed information about the methodology of LCA is presented in publications of the SETAC (Society of Environmental Toxicology and Chemistry) and ISO. 

International organizations, like SETAC and ISO, have worked on the harmonization of LCA methodology. 

There are several sources of information on LCA methodology and of LCA studies. There are a considerable number of cross-references in these information sources, so only a few of them need be considered here in order to provide a starting point for further studies. 

Advisory Group are considering different facets of LCA. In 1993, they developed the Code of Practice ,the first worldwide accepted technical framework for LCA. This was an important step towards the harmonisation of the method and has initiated and supported the standardisation process by ISO. Between 1997 and 2000, ISO produced the international series of standard defining the different stages of the LCA methodology (ISO 14040 1997, ISO 14041 1998, ISO 14042 2000 ° as well as ISO 14043 2000° ). As mentioned above, these standards were replaced by two improved editions of life cycle assessment standards in 2006 (ISO 14040 2006 and ISO 14044 2006°). 

For useful reviews of LCA methodology and apphcations to processes, see Azapagic and Burgess and Brennan. The journals Journal of Cleaner Production (Elsevier) and Process Safety and Environmental Protection (Inshtuhon of Chemical Engineers) include a number of articles on LCA-based studies. 

In this study, LCA methodology of a full cradle-to-grave or business-to-consumer carbon footprint approach is used to draw the general map of energy consumption, and later any possible savings opportunities are analyzed and appropriate action plans are structured. In Table 2.5 life cycle stages that are included and also excluded in the conducted work are listed. 

The methodology of inventory analysis is well-developed in comparison to the other components of LCA. Some practitioners still prefer to use the inventory as the sole base for improvements, claiming that the impact assessment step is still not sufficiently developed. While it is true that the inventory stage is sufficient to simply identify the emissions, it does not evaluate their relative environmental impacts. For this an impact assessment is necessary. 

---