Life Cycle Assessment system boundaries

Figure 15.9 System boundaries of the Life Cycle Assessment of potato starch based packaging. (Reprinted from Murphy et al., 2004, with permission from British Potato Council, UK).

A three-step methodology for activity-based environmental inventory allocation is useful in calculating data for the first step of life cycle assessment. First, the process flow and system boundary... 

Ekvall, T., Weidema, B.P., 2004. System boundaries and input data in consequential life cycle inventory analysis. International Journal of Life Cycle Assessment 9, 161—171. 

LCSA extends the environmental boundaries of traditional LCA in an attempt to incorporate the concept of sustainable development. It is defined as a method of addressing environmental, economic, and social sustainabiHty of a product system over its life cycle, indicated through the measurement of either positive or negative impacts [3]. LCA has been implemented through an integration of E-LCA, hfe cycle costing (LCC), and social life cycle assessment (S-LCA) [3]. Brief definitions of E-LCA, LCC, and S-LCA are described in Table 14.1. 

The system boundaries of an LCA may extend from cradle to gate, cradle to grave, or cradle to cradle. As depicted in Figure 26.1, cradle to gate implies that the life cycle assessment covers activities prior to the use phase, while cradle to grave includes the product s use and end of life. Cradle to cradle indicates a product that can be disposed of and returned back to the natural environment the life cycle of PLA can be considered as such because when PLA degrades, its carbon is recycled back into the environment for uptake by biomass. 

The cradle-to-factory gate system boundary is justified on the basis of all forms of PDO have the same use and end-of-life impacts. However, life-cycle assessments of polymers are frequently sensitive to assumptions regarding end-of-life disposition (J2). Additional analyses taking a cradle-to-grave perspective including use and waste management should be conducted. 

When starting a Life Cycle Assessment the first task is the definition of goal and scope. As already mentioned the setting of system boundaries for products based on renewable resources is not straightforward. In order to exemplify die influence of the question what shall be included on the result of the assessment three different scenarios will be compared for the life cycle of biodiesel from tallow and used vegetable oil (see Figure 1). 

FIGURE 11.2 Life-cycle system concept showing the boundaries on which the life-cycle assessment must be performed. (Reprinted by permission of the pubhsher from Curran, 1996.)... 

Pollution prevention is another area that should be viewed with life-cycle impacts in mind. In P2 assessment, the system boundaries are drawn very narrowly around the chemical activity. Figure 4.3 shows how boundaries for pollution prevention as-... 

Description of process/environment Quality-related critical parameters Purpose and objectives of the system Major benefits of the system Special requirements Specific training needs System operating strategy Related GMP compliance/regulations Physical and logical boundaries System GMP risk assessment System validation rationale Life-cycle documentation Assumptions and prerequisites Limitations and exclusions Quality-related critical parameters/data Standard operating procedures System requirement specification Supplier and system history... 

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... 

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. 

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. 

---