Life cycle inventories results

Table 6 Summary of Life-cycle Inventory Results for 1.0 MSF 3/8-inch Basis Plywood Production in the Pacific Northwest Region—a Comparison of Total to Site-generated Emissions (From Ref. 12)...

Table 8.11. Key life cycle inventory results for some compostable polymer materials [1,22]... 

A comparison of the life cycle inventory results for pellets, loose fills and films/bags is given in Table 13.9. Only those impact categories are listed for which at least one dataset was available by type of product. 

Once the life-cycle inventory has been quantified, we can attempt to characterize and assess the eflfects of the environmental emissions in a life-cycle impact analysis. While the life-cycle inventory can, in principle at least, be readily assessed, the resulting impact is far from straightforward to assess. Environmental impacts are usually not directly comparable. For example, how do we compare the production of a kilogram of heavy metal sludge waste with the production of a ton of contaminated aqueous waste A comparision of two life cycles is required to pick the preferred life cycle. 

Life Cycle Interpretation. The results obtained within the Life Cycle Inventory and/or the Life Cycle Impact Assessment are interpreted in the light of the Goal and Scope Definition (e.g., by means of sensitivity or uncertainty analyses) in order to draw conclusions and make recommendations. ... 

The core of LCA is a cradle-to-grave life-cycle inventory analysis that is fundamentally an engineering exercise describing a chemical, material, and energy accounting balance for the entire product system. The various inputs and outputs are collected or inventoried for each unit operation in the defined system (see fig. 4.4). A key qualifier in the figure is the definition of the system boundary, as it will directly affect the quality of the final results and conclusions. The inventory practice and methods are relatively well defined. 

Peereboom, E., R. Kleijn, S. Lemkowitz, et al. 1998. Influence of inventory data sets on life-cycle assessment results A case study on PVC. J. Ind. Ecol. 2 109-130. 

The inventory stage involves the collection of all the data that will be used in the life-cycle analysis. The quality of the data is an important part of the life-cycle inventory (LCI) process, and, as with any model, the results of an LCA are only as good as the data inputs. There are two basic sources of data for an LCA, primary and secondary in nature. Primary data are derived directly from the... 

The chapter starts with a description of what silk is, where and how it is produced, focusing on South Indian sericulture. We then review the existing silk LCAs and other environmental assessments that underpin this study. Following an overview scope and overview of the life cycle inventory (LCI), and results, the discussion compares the environmental impacts of silk with those of other natural fibres. Major contributors to the high observed impact ( hotspots ) are described and opportunities and barriers improvement outlined. 

Life-Cycle Inventory analysis result (LCI result) provides information about all inputs and outputs in the form of elementary flow to and from the environment from all the unit processes involved in the study. An outcome of a life-cycle inventory analysis result includes the flows crossing the system boundary and provides the starting point for life-cycle impact assessment. 

An inventory analysis compiles the flows of materials and energy into and out of the system. Necessary work consists of construction of a flow model, data collection, and calculation of results. In other words, the phase of life-cycle inventory (LCI) provides the systems model of the technical system ( product system ) under study, complying with the goal and scope definition. This model consists of certain elements, which in terminology of the ISO standards are the following ... 

Life cycle inventory (LCI) is a methodology for estimating the consumption of resources and the quantities of waste flows and emissions caused or otherwise attributable to a product s life cycle [3]. The inventoiy analysis constitutes a detailed compilation of all of the environmental inputs and outputs to each stage of the life cycle [10]. The inventory usually includes raw material and energy consumed, emissions to air and water, and solid waste produced. The processes within the life cycle and the associated material and energy flows as well as other exchanges are modelled to represent the product system and its total inputs and outputs from and to the natural environment, respectively (Fig. 8.2). This results in a product system model and an inventory of environmental exchanges related to the functional unit. 

The International Standard Organization (ISO 14040) [26] breaks the LCA framework into four main stages (1) Goal and scope definition of the study. This stage clarifies the purposes of carrying the study while the assumptions and system boundaries are described clearly. (2) Life Cycle Inventory (LCI) analysis. LCI involves data collection and calculation procedures to quantify relevant inputs and outputs of the entire system defined within the system boundaries. (3) Life cycle impact assessment involves qualifying the potential environmental impacts of the inventory analysis results. (4) The interpretation of the results from the previous phases of the study in relation to the objective of the study. This interpretation can be in form of conclusions and recommendations to decision-makers for process changes to deliver improvement in the environmentel performance. 

The life cycle inventory analysis (ii) involves data collection and calculation procedures to quantify the total system s inputs and outputs that are relevant from an environmental point of view, that is, mainly resource use, atmospheric emissions, aqueous emissions, solid waste, and land use. The LCIA (iii) aims at evaluating the significance of potential environmental impacts using the results of the life cycle inventory analysis. The life cycle interpretation (iv) is the final step of the LCA where conclusions are drawn from both the life cycle inventory analysis and the LCIA or, in the case of life cycle inventory studies, from the inventory analysis only. The important LCA requirements are given in Figure 15.5 [150]. 

Most LCAs are performed only xmtil Step 2, since impact assessment and interpretation involve many more qualitative assumptions. In this case, LCA are called life cycle inventories (LCIs). This latter is a tool required to estimate the direct and indirect inputs of each step of a biofuel pathway. The results are the use of resources (eg, energy consumption) and the environmental emissions (eg, CO2, sulfur oxides, nitrogen oxides). LCIs permit the assessment of impact categories, such as climate change, photooxidant formation, acidification, eutrophication, ecotoxicity and human toxicity, and the depletion of biotic and abiotic resources. These factors of the LCI will be converted into environmental damages. Various indicators can be derived from these mechanisms at intermediate levels (midpoints) or damage levels (endpoints) after normalization, often weighting approaches. 

In Sect. 3.2, we review the literature on short life-cycle inventory replenishment. In Sect. 3.3, we formulate the problem in Sect. 3.4, we state our heuristic and establish optimality conditions in Sect. 3.5, we show how to modify the process when customers may return merchandise and in Sect. 3.6, report results on our application. 

The inventory results should be presented in clear form, how much and what substances from the environment enter the system and how much get out. These results serve for subsequent life cycle impact assessment [48], The aim of the life cycle impact assessment is to measurably compare the environmental impacts of product systems and to compare their severity with new quantifiable variables identified as impact category. The impact categories are areas of specific environmental problems such as global warming, climate changes, acidification, eutrophication, ecotoxicity and others. Already in the phase of definition of the LCA study scope, it is necessary to describe what impact category will be applied and which of their environmental mechanisms will serve as a basis for impact assessment [46],... 

The aim of the Life Cycle Impact Assessment (LCIA) is to facilitate the interpretation of the results of the inventory analysis. The result of the inventory analysis is an emission profile for each alternative system. In this study the emission profile is the total of all emissions to air, water and soil from the grave-to-cradle chain for the use of cushion vinyl floor covering, including the up chain processes, like electricity production and the down chain processes, like the incineration and landfill of the waste. Such an emission profile may consist of hundreds of emissions and extractions. In LCA impact assessment the total of interventions (emissions, extractions) of a process chain is evaluated in terms of environmental problems (impact categories). 

LCIA provides indicators for the interpretation of the inventory data in terms of contributions to different impact categories. The indicator results of an LCIA facilitate the evaluation of a product, and each stage in its life cycle, in terms of climate change, toxicological stress, noise, land use, water consumption, etc. The scope of the evaluation is, with some exceptions, limited to impacts at a regional and global scale. 

There are also several points in an LCA that can significantly change the result of a study. These are, among others the functional unit, system boundaries (geographical, natural as well as life cycle), data quality, and allocation. A traditional problem in LCA is how to deal with processes or groups of processes with more than one input and/or output, and how to deal with the use of recycled material in another product than the original. A crucial problem of evaluation and interpretation of the inventory results is that they depend on social and political preferences rather than on technical development. 

The inventory data and the classified and characterized results are the ecological profile of the product or product system under study. These profiles may be used as modules for the life cycle assessment of subsequent products, for which these products are input of goods (e.g. LCl data of a steel production analysis are the basis for an LCA of a car made of tailored blanks such as building material profiles, for example, may be used to analyze buildings). A prerequisite for this is however that the methods and background data used for the modeling of the systems are identical. 

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