is conducted to assess whether a product or system meets certain environmental standards, or whether it is more environmentally sound than another product or system); comparative assertion disclosed to the public (environmental claim regarding the superiority or equivalence of one product versus a competing product which performs the same function)


It is self-evident that in a situation of global exploration or company-internal innovation, there is, in general, less need for process regulation than in a situation involving disclosure or justification to the public. For process situations in between these two extremes it is important to realise what impact the LCA’s results can have for the parties involved. In such situations, there may be potential interests which could be important for long-term strategies, but one or more of the parties could also be affected by more short-term interests. 1 Part 1 (Section 2.3) also mentioned another evolving type of LCA application: LCA as a management tool on a more continuous basis, as in benchmarking. This type of application has not been given any specific attention during the work on procedures described here. 1.2 Part 2a: Guide

Guinée et al., Handbook on LCA: Operational Guide to the ISO Standards (2002)


Part 2a: Guide Note that determining the decision situation in advance of the execution of the LCA study does not imply that the decision to be taken is already fixed. It only implies that a certain decision is aimed for and that a number of procedural arrangements may be necessary. With respect to the process context, four categories can be defined by making distinctions on grounds of diverging interests and on the relative potential impact of the LCA’s results on the stakeholders. In the case of global exploration of options, there are generally few diverging interests, and there is a weak impact. In such a situation, a process approach is unnecessary. In the remaining three cases, process design needs to be attuned to the various process contexts


In such a situation, a process approach is unnecessary. In the remaining three cases, process design needs to be attuned to the various process contexts. These are described below: process context I: few diverging interests, potentially strong impact; process context II: many diverging interests, potentially weak impact; process context III: many diverging interests, potentially strong impact. Figure 1.2.1 helps to determine the process context that is applicable. Process management in LCA Many LCAs are conducted as company-internal matters. They may be restricted to a general exploration of the environmental burden associated with specific options, in which case the procedural approach to the LCA project can remain a purely internal affair. But the results of LCA projects often have more far-reaching implications, in that policy choices, investments and other important decisions may be driven by them


But the results of LCA projects often have more far-reaching implications, in that policy choices, investments and other important decisions may be driven by them. Realisation of a correct and transparent process involves shaping the execution of the process in accordance with the process design, as arranged by the various parties involved. In the case of processes in context III (above), the appointment of an independent process manager is recommended. 1.3


The next chapters of this Guide provide procedural guidelines for the process management of the separate phases of LCA. In the meantime, the following general principles can be given: Process rules according to the decision situation All procedural guidelines for the specific LCA phases are given for the three distinct types of process context. In general, context III is the most complex and requires the most detailed rules. Process rules based on guidelines for LCA phases The exact definition of the guidelines does not depend on the complexity of the LCA itself, but rather on the complexity of the interests of the parties involved. It is possible, for instance, that a relatively simple LCA will require a detailed LCA process – because of the varied interests of those involved. This implies that the procedural guidelines only provide a general basis for detailed process rules, which themselves have to be designed by the parties involved in a given situation


This implies that the procedural guidelines only provide a general basis for detailed process rules, which themselves have to be designed by the parties involved in a given situation. Process design based on general guidelines The following nine guidelines can form the basis for process design: Entry guideline The following parties should be invited to be part of the decision-making process: all who have an interest in the results of the LCA and those who could influence or block the purpose of the LCA. This basic rule will need to be worked out in each specific context. It may be necessary to involve more parties – because of policy considerations – or to r estrict the number, in the interest of management considerations. Consensus guideline The most important guideline for decision-making is to have decisions made by consensus, and to use a majority of votes, arbitration, or another previously determined procedure for decision-making only if there is no other alternative


The reason is that those who find themselves in the minority a few times may lose commitment to the process and so to the final result. Minority gets a say It is important that minority wishes should be granted if they do not run counter to the majority view. For example, a minority party may want a supplementary analysis to be conducted. Granting such a wish is sensible, because it will increase the authoritativeness of the final result of the LCA. If the wish is not granted, the minority may dissociate itself from the final conclusions. Test of professionalism When parties negotiate the formulation of an assignment or an interim report, they may, in the interest of consensus, produce an assignment or statement that turns out not to be up to scientific standards in terms of content. For instance, the formulation of the assignment could contradict the core scientific content of this LCA Guide


For instance, the formulation of the assignment could contradict the core scientific content of this LCA Guide. In such cases, the investigators should test the content of the parties’ statements and report explicitly when they find a statement debatable in scientific terms. Reporting in the case of a conflict between investigators and stakeholders In such cases, the investigators' opinions should be explicitised in the LCA report. This allows the investigators to keep their professional integrity intact, while stimulating the stakeholders to revise their opinion. Part 2a: Guide


Explicitness Stakeholders may have conflicting opinions about, for example, the formulation of an assignment, about the quality of the result of an investigation or about the analysis of such results. The rule of explicitness ensures that the stakeholders make such differences of opinion explicit. They must indicate – preferably in writing – what they understand the difference of opinion to be. External test rule (critical review or peer review) This rule states that there should be external testing of certain aspects of an LCA project during the process by independent critical review


External test rule (critical review or peer review) This rule states that there should be external testing of certain aspects of an LCA project during the process by independent critical review. ISO10404 states that the critical review shall ensure that: the methods used to carry out the LCA are consistent with the ISO standards on LCA; the methods used to carry out the LCA are scientifically and technically valid; the data used are appropriate and reasonable in relation to the goal of the study; the interpretations reflect the limitations identified and the goal of the study; the study report is transparent and consistent. A critical review could, for instance, be applicable to an interim LCA report, or to specific issues giving rise to conflict between investigators and stakeholders, or to conflict between stakeholders


But it may be useful to have a critical review carried out in any case, by way of overall error check, and to justify the reasonableness of assumptions, the appropriateness of data and the correctness of methods. Reporting in the case of a conflict between stakeholders This second reporting rule allows for unresolved conflicts between stakeholders to be described in the final report. In such cases, one or more stakeholders may dissociate themselves from the results because they feel the LCA guidelines have not been properly applied. The reporting rule requires that a judgement by the research institute and a critical reviewer be added to the stakeholders’ opinions. On the one hand, this does justice to minority opinions, since these are noted in the final report. On the other hand, strategic behaviour is exposed, since it will become evident if minority views cannot stand up to a critical appraisal of their content


On the other hand, strategic behaviour is exposed, since it will become evident if minority views cannot stand up to a critical appraisal of their content. Iteration rule One or more stakeholders may require iteration, particularly in the last two process steps. If all parties agree, there is no problem, but if a minority group wants iteration, a conflict may arise. Other parties may wish to end the investigation. The iteration rule says that if a minority wants iteration of the last two steps, this should be allowed. It should be realised that a process involving many parties cannot be driven by rules alone, and that the way the process is managed is equally important. Can the process manager create sufficient confidence that all parties will participate in all consultations arising from the LCA project? This is important, since each guideline can be used by uncooperative parties for their own ends, particularly to slow down the whole process


It is up to the process manager to make it clear that everyone profits from a proper application of the rules – and that they all suffer if the rules are abused. There is much to be gained if the manager can make this clear to all concerned. Organisation and assignment Before the start of the executive work in the first phase of LCA (the Goal and scope definition; see Chapter 2), the organisational set-up needs to be established. The following points have to be taken into consideration. 1.4 Part 2a: Guide


Selection of stakeholders Selection of the interested parties should be based on the entry guideline described above. ISO 14040 identifies a number of possible categories of participants in the example of a ‘comparative assertion that is disclosed to the public’ requiring a critical review. Assignment The actual execution of the first phase of a study should follow a clearly formulated assignment procedure. In LCA, this formulation should not be regarded as merely a necessary preparatory activity, but rather as an important first step and as part of the execution itself and the underlying process. The execution of the first phase (the Goal and scope definition) is so closely connected to the formulation of the assignment that intensive interaction between the LCA client and the LCA researchers will be necessary. In practice, it has been noted that lack of foresight at the assignment stage creates certain risks


In practice, it has been noted that lack of foresight at the assignment stage creates certain risks. Unjustifiable simplifications must be avoided - as must extrapolation of the LCA results. For instance, if the analysis aims at a general comparison of two types of product systems, it is insufficient to merely compare a few specific cases. The process design also needs to describe how the assignment might be revised in the light of new information, such as changes in the intended use of the LCA, the involvement of stakeholders, LCA quality requirements, and so on. Project organisation The organisational set-up of a properly carried out LCA project requires the initiator to pay particular attention to the first steps, followed by a common approach shared by the stakeholders. From the start, the competencies of all parties should be established, with respect to both the set-up and the other four phases


From the start, the competencies of all parties should be established, with respect to both the set-up and the other four phases. Revising important principles, the formulation of the assignment, and/or process planning should all be avoided during the actual execution of an LCA. Therefore, a well-planned process design and management are essential


This is best done by focusing attention on the following key points: views on assignment, process planning and process management; selection criteria for parties to be involved in the process; possible choice of an independent process manager; description of the intended use of the LCA results in the assignment, and the feasibility of that use in terms of the budget and limitations of the LCA; description of the intended quality of the LCA results in the assignment; intentions with respect to the execution of one or more critical reviews (under ISO it is possible to choose a critical review and/or panel review); intentions with respect to the extent of transparency of the report, regarding principles, data, assumptions, choices and so on; methods of obtaining an independent validation of non-public data and/or data delivered by interested parties (critical review); other process principles, process intentions and intended procedures required to achieve the proper course of the


of non-public data and/or data delivered by interested parties (critical review); other process principles, process intentions and intended procedures required to achieve the proper course of the process; possible departures from the guidelines during the course of the process and the motivation for such deviations


Part 2a: Guide


Reporting an LCA project Reporting is a crucial issue in LCA. A technically excellent LCA without a transparent and unambiguous report will be of very limited value. This applies not only to external studies but also to internal studies. The requirements for external studies are clear: claims made to the public, the use of results by governments and all other applications which involve third parties will require that these third parties can see which choices and assumptions have been made, which parts of the life cycle have been excluded, which data have been used, and so on. For internal studies there is not primarily a need with regard to third parties, but third parties may become involved over time, as experience has shown that companyinternal innovation studies sometimes come to be used outside the company. Even for purely internal purposes, however, clear reporting is of prime interest


Even for purely internal purposes, however, clear reporting is of prime interest. An LCA may often spawn product or process improvements, and after a year or so there may be an update study which builds on the original one. Moreover, the steps involved are complicated and there are many points at which data are needed and assumptions and choices have to be made. The baseline quality of an LCA can only be guaranteed if all steps undertaken are clearly reported. It is therefore only natural that a Guide for LCA should include guidelines for setting up a clear report. The chapters below provide many guidelines indicating how specific issues (choices, assumptions, data, calculation rules, results, conclusions) are to be reported. But there are also certain general principles for reporting LCA. There are three main guiding principles: all issues should be reported; all issues should be reported in a transparent way; all issues should be reported explicitly


There are three main guiding principles: all issues should be reported; all issues should be reported in a transparent way; all issues should be reported explicitly. However, if we adhere to these main principles, reporting on an LCA becomes an extremely time-consuming activity, and LCA reports become huge documents. Fortunately, the present Guide and related documents have “pre-digested” a large number of choices and data, and a simple reference to this Guide and the related texts will often suffice. For instance, Part 2b of this Guide contains dozens of pages with characterisation factors. If these are used in a case study, a proper reference may replace the retyping of these tables. Note, though, that a proper reference is still needed at the appropriate place. What holds for data also holds for argumentation


Note, though, that a proper reference is still needed at the appropriate place. What holds for data also holds for argumentation. ISO’s requirement to justify the environmental relevance of the choice of impact categories in an Impact assessment, for instance, can be addressed by referring to the discussion in specific chapters of Part 3 of this Guide. Nevertheless, reporting on an LCA requires a careful planning and is likely to result in a main report of 20-80 pages, accompanied by annexes with process data and specific characterisation factors, comprising some 50-500 pages, depending on the goal and scope of the LCA. The main report in particular is something that should be planned. Again, the present Guide may assist in the process of writing such a report. It provides certain sample tables that may serve as blueprints for the tables in the main report. This is also true of the structure of the present Guide


It provides certain sample tables that may serve as blueprints for the tables in the main report. This is also true of the structure of the present Guide. It is strongly recommended to have separate chapters for the different phases of an LCA. A blueprint for a report could look as follows: Summary Introduction Procedures Goal and scope definition Inventory analysis Impact assessment Interpretation Final conclusions Moreover, many of the steps identified in this Guide should preferably be included in such a report, e.g., economy-environment system boundary, flow diagram, etc. Some of these 1.5 Part 2a: Guide


steps (e.g., calculation method, classification) may only require a short text, while other steps (e.g., data collection and relating data to unit processes, sensitivity analysis and uncertainty analysis) may require a large number of pages, including tables, figures and annexes. Reporting quantitative results poses special requirements. The following issues need attention. Figures that represent quantities, such as mass or volume, are figures relating to units. The units agree with the dimensions of the quantities, and should always be explicitly reported. The guidelines below recommend the use of SI units. Figures should never suggest greater precision than is appropriate. For instance, pocket calculators and computer programs often produce results in 8 digits, but only a few of them are significant. Thus, 1/3 should be written as 0.3, not as 0.33333333. Figures suggest precision, even if the number of significant digits is limited


Thus, 1/3 should be written as 0.3, not as 0.33333333. Figures suggest precision, even if the number of significant digits is limited. When standard errors are available, these may be added, indicated by"±". In other cases, ranges may be available. Use a table to present large sets of figures. In some cases, graphic representation may be useful. However, the design of good graphs is not without its problems. Some issues include the following. Add labels for the quantity represented, its unit and the numerical values for at least some of the marks of the axes. Be cautious about using one graph to display different quantities at the same time. Be cautious about using logarithmic axes. Do not limit figure captions to a mere "Figure 12: Results of the characterisation"; expand them to include explanatory material. As will be clear from the text below on procedures for the various phases of LCA, there will in general be a draft interim report and a final report after revision


As will be clear from the text below on procedures for the various phases of LCA, there will in general be a draft interim report and a final report after revision. It is also emphasized in many places that LCA is an iterative process, which includes regular checks to see whether the choices made are consistent with the goal and scope of the study. It follows that reporting LCA is also an iterative process. It is not a matter of defining procedural steps, gathering data, making calculations and then writing a report. Procedural issues are everywhere in the LCA process, and good decisions by clients, stakeholders, LCA researchers and critical reviewers can only be made on the basis of written documentation, like a draft interim report. The initialising phase of defining the goal and scope is crucial in this respect. Many choices are made here, relating to purpose, intended application, product alternatives, scope of the analysis, and so on


Many choices are made here, relating to purpose, intended application, product alternatives, scope of the analysis, and so on. It also points out where data gaps can be expected, which pitfalls may show up, how much time will be needed for the rest of the LCA, what additional information may be needed, and so on. In practice, a fairly complete report on the Goal and scope definition often serves as a milestone in the LCA project. It provides a good point for rethinking the goal and scope, for allocating budget, for appointing additional reviewers and for deciding whether to continue the project at all. As such, a so-called Goal and scope report plays an important role. One should realise that a Goal and scope report in this sense may be quite different from the chapter on Goal and scope definition in the final complete report, precisely because the Goal and scope report may induce a focus for the goal, a change in scope, or some other major modification of the final LCA plan


Moreover, a Goal and scope report will, in principle, include all of the chapters of the final report (see the list above), although most chapters (Inventory analysis, Impact assessment, Interpretation) will not yet include any results, but only outline the main choices to be made during these phases. Part 2a: Guide


Example (case history) Since the late 1980s, Unilever has conducted many LCA-type studies for almost all its major product groups, including margarine, ice cream, detergent and shampoo. Both in the UK and in the Netherlands, various specialists have developed the necessary skills, and have built up a substantial database. Thanks to this expertise, they have been able to explore improvement options in all parts of the process chain of their products. Unilever has also conducted in-house environmental and market-economic comparisons between one-way and multiple-way packaging for several of its products. These studies were part of the Dutch Packaging Covenant, and have contributed to the formal decision-making process in the Netherlands, involving the government, NGOs, academia and the business community. Its extensive experience has also enabled the company to conduct a so-called Overall Business Impact Analysis, which formed the basis of its 1998 Environmental Report


Its extensive experience has also enabled the company to conduct a so-called Overall Business Impact Analysis, which formed the basis of its 1998 Environmental Report. This study estimated the combined environmental impact related to the generation of all raw materials, the manufacturing of all products and the use of those products, and related this to Unilever’s economic contribution. The outcome of this study has led Unilever to formulate three main environmental focus areas, viz. sustainable agriculture, sustainable fishing and clean water stewardship. As a consequence of these initiatives, life cycle thinking has become common practice in many places within the company. Although full-scale LCA studies are rarely being conducted anymore, the expertise which has been built up helps to formulate improvement options and to monitor the improvement process


Although full-scale LCA studies are rarely being conducted anymore, the expertise which has been built up helps to formulate improvement options and to monitor the improvement process. The next chapters of this part of the Guide describe competencies and responsibilities, together with brief guidelines for handling potential bottlenecks in the various LCA phases by making arrangements that will guarantee the smooth progress of the whole project. 1.6 Part 2a: Guide


Goal and scope definition Recipe Page Procedures Goal definition Scope definition Function, functional unit, alternatives and reference flows Topic The Goal and scope definition is the phase in which the initial choices which determine the working plan of the entire LCA are made. The goal of the study is formulated in terms of the exact question, target audience and intended application. The scope of the study is defined in terms of temporal, geographical and technological coverage, and the level of sophistication of the study in relation to its goal. Finally, the products (or product) that are the object of the analysis are described in terms of function, functional unit and reference flows. Starting points The general starting points for the LCA as elaborated in this Guide are as follows


Starting points The general starting points for the LCA as elaborated in this Guide are as follows. There is a focus on change-oriented, structural decisions, that is, the method is mainly intended to support decisions with respect to changing a situation, for instance from one material to another, and for decisions that are assumed to be effective for an indefinite time. There is a focus on the main function of a product; possible other functions are identified but ignored or carried over through an allocation step. There is no specific focus on particular processes, chemicals, environmental impacts, countries, years and so on. In principle, the analysis covers all processes (cradle-to-grave), taking place at all locations and throughout the entire life cycle period, and includes extractions of natural resources, releases of chemicals, use of land, and all impacts resulting from these interventions


We have made ISO 14040/14041 the general starting point of the Goal and scope definition and Inventory analysis phases. The ISO requirements have since been made operational through the work of the SETAC Working Group on Inventory Enhancement and many individual projects. The steps for Inventory analysis laid out in the next chapter of this Guide are copied from ISO 14041, with a few adaptations. For a justification and explanation of these adaptations, see Part 3 of this Guide. The requirements of ISO 14041 have been closely followed, with certain additions or further specifications


For a justification and explanation of these adaptations, see Part 3 of this Guide. The requirements of ISO 14041 have been closely followed, with certain additions or further specifications. These are: the distinction between two modes of analysis – descriptive and change-oriented; a clearer distinction between reporting the main choices to be made in the Inventory analysis, Impact assessment and Interpretation parts of Scope Definition, and in the Inventory analysis, Impact assessment, and Interpretation phases themselves; the implementation of an analysis of the data quality in the section on key issues for sensitivity analysis; the latter is conducted as part of the Interpretation phase; the choice between actual, standard and recommended performance of products has been shifted to the Inventory analysis phase. Further information about the individual steps within the Goal and scope definition phase can be found in Part 3. 2. 2.1 2.2 Part 2a: Guide


Recipe Procedures Topic The procedural organisation should allow for a common treatment of all general and specific subjects that the parties involved will want to discuss during this first LCA phase. Attention should particularly be given to the following issues: normative choices to be made prior to defining the goal and scope; choices with respect to details of the construction of product systems and scenarios that will be analysed and/or compared; choices with respect to the reliability, validity and sensitivity of LCA input and output; possibilities for adjusting the details of the assignment and/or LCA process design; intentions for the approach to be used in the subsequent phases (including allocation and weighting); further LCA process planning and LCA process management. Main choices The procedures in the LCA study must be laid down right from the start of the Goal and scope definition phase. First, a supervision process must be set up


Main choices The procedures in the LCA study must be laid down right from the start of the Goal and scope definition phase. First, a supervision process must be set up. The project initiator should carry out the first steps, while the stakeholders arrange the organisational set-up of the project. During this initial phase of the LCA, the supervision process must be set up with due regard to the authoritativeness of the study results. Input from the stakeholders must not be ignored. There must be interaction between all parties involved on topics that are relevant to the goal and scope of the study. Guidelines Determine the LCA process context by means of the decision tree in Chapter 1 (Figure 1.2.1). Determine the competencies and responsibilities of the LCA research scientists, critical reviewers (if any), the LCA clients and other interested parties, using Table 2.3.1


Determine the competencies and responsibilities of the LCA research scientists, critical reviewers (if any), the LCA clients and other interested parties, using Table 2.3.1. Address potential bottlenecks in the LCA process by making arrangements on the basis of Table 2.3.2 to ensure the orderly progress of the project. 2.3 2.3.1 Part 2a: Guide


Table 2.3.1. Overview of the competencies of the various actors during the LCA process for the different process contexts


Item 1a 1b 2a 2b 3a 3b Description first instructions with respect to fulfilment of LCA assignment first instructions with respect to fulfilment of the assignment of a critical reviewer written response to instruction on LCA assignment written response to instructions on assignment of a critical reviewer possible revision of the first instructions on LCA assignment possible report on incompatible opinions on LCA assignment presentation of draft interim report (= draft text of Goal and scope definition) written reaction to draft interim report on Goal and scope definition possible revision of draft report on Goal and scope definition possible report on incompatible opinions arising during the goal and scope definition final opinion on final interim report on Goal and scope definition Process context I C - L - C L L C L L C II C or S L + R R C or S L L + R C or S L + R L C or S S L + R R S L L + R S L + R L S Legend Process context I = few diverging interests, potentially strong impact


context I C - L - C L L C L L C II C or S L + R R C or S L L + R C or S L + R L C or S S L + R R S L L + R S L + R L S Legend Process context I = few diverging interests, potentially strong impact Process context II = many diverging interests, potentially weak impact Process context III = many diverging interests, potentially strong impact C = first LCA client(s) S = stakeholders (including C) L = LCA research scientists R = critical reviewer Table 2.3.2 Overview of the arrangements that can be made between the various actors for the different process contexts


Item a b c d e Description I widening/supplementation of the study (on o request) validation by an independent expert (on request) o binding advice on contentious issues by the o critical reviewer final decision-making by the largest possible o majority, arbitration or another previously determined procedure quantification of the influence of incompatible o opinions in the final report Process context II III r r r r r r o r r r 1 The actual implementation of all guidelines in this Guide should be checked in a critical review. Part 2a: Guide C or S S III


Legend Process context I = few diverging interests, potentially strong impact Process context II = many diverging interests, potentially weak impact Process context III = many diverging interests, potentially strong impact r = recommended o = option Example (case history) No example. Goal definition Topic The first step in the Goal and scope definition phase involves stating and justifying the goal of the LCA study, explaining the goal (aim or objective) of the study and specifying the intended use of the results (application), the initiator (and commissioner) of the study, the practitioner, the stakeholders1 and the intended users of the study results (target audience). Main choices The goal, application, initiator, stakeholders and commissioners must always be defined as unambiguously as possible. A special case is that of the so-called comparative assertions disclosed to the public


A special case is that of the so-called comparative assertions disclosed to the public. LCAs reporting on such studies have been a source of controversy in quite a few instances in the past, and therefore require special care. Guidelines State the goal(s) of the study unambiguously and transparently, not only in terms of what is to be done (e.g., comparing systems A and B, carrying out a cradle-to-gate or cradleto-grave analysis, hot-spot identification, etc.), but also in terms of the reasons for executing the study. The intended application(s) and decision(s) to be supported should be defined as precisely as possible. Determine whether the goal meets the definition2 of “Comparative assertion disclosed to the public”


Determine whether the goal meets the definition2 of “Comparative assertion disclosed to the public”. List the parties involved: those undertaking the study (the researchers) and their affiliations and LCA experience; the LCA commissioner (the client and/or the funding body); the target audience (or users) and other interested parties; the members of the steering committee or any other supervising committee; the expert reviewer(s) and/or members of an expert review panel. Determine whether LCA is the most appropriate tool to answer the specific research question, or whether other instruments may be more suitable for the goal defined. State the possibilities and limitations of LCA clearly, and clarify the potential value of the use of other tools in addition to LCA (see Part 1 for limitations and other tools). 1 Referred to in ISO 14040 (1997E) as “interested parties”


1 Referred to in ISO 14040 (1997E) as “interested parties”. 2 An environmental claim regarding the superiority or equivalence of one product versus a competing product which performs the same function. 2.3.2 Part 2a: Guide


Check and report whether the general starting points for all phases of the LCA (Goal and scope definition, Inventory analysis, Impact assessment, Interpretation) as described in Sections 2.2, 3.2, 4.2 and 5.2 have been followed. Any deviations from these starting points should be reported and justified. See the general reporting issues (Section 1.5) for the preferred way to report these issues. Check the formulation of the goal(s) (in relation to the limitations of LCA as stated before). Consider whether adjustments of the goal are necessary or whether there are issues that have to be analysed further in the Interpretation phase. The thoroughness of the check and the extent of the adjustments can vary from minor for a simplified LCA to major for a detailed LCA. If product alternatives are to be compared, determine which differences in results are large enough to allow the conclusion that a certain product alternative is more environmentally sound than another


Example (hypothetical) “The goal of the LCA is to identify options for improving the environmental performance of the material polyethylene in disposable bread bags. The results of this LCA will be used for product and process development. The plastic bag manufacturer wants to be able to analyse the effects of changes in its processes, in terms of technology, inputs and product composition, on the total environmental impact. This information, in turn, can be used to prioritise different measures that can be taken to improve the environmental performance. This LCA does not aim at a public comparative assertion. The study is conducted by Pro-Duct Consultancy Ltd, a moderate-sized private engineering bureau. The commissioner is Bag-Away, a large producer of plastic disposable bags. Interested parties are mainly the plastics industry, bakeries and shops. A steering committee with representatives of the producer, the ministry of the environment and academia will be formed


Interested parties are mainly the plastics industry, bakeries and shops. A steering committee with representatives of the producer, the ministry of the environment and academia will be formed. Finally, an expert review will be carried out at NILCAR, the National Institute for LCA Research.” Scope definition Topic The Scope Definition step establishes the main characteristics of an intended LCA study, covering such issues as temporal, geographical and technology coverage, the mode of analysis employed and the overall level of sophistication of the study. A so-called Goal and scope report (see Section 1.5) may also be drafted for the sake of critical review and comments from interested parties. This report should justify all the main choices with respect to the step “Function, functional unit, alternatives and reference flows” and the phases of Inventory analysis, Impact assessment and Interpretation


Main choices The guidelines given in this Guide are basically intended for change-oriented, structural decisions. The emphasis in the guidelines is on detailed LCA, in which simplified guidelines have been derived from the detailed ones, and extended guidelines have been designed as add-ons to the detailed ones. Guidelines are for so-called cradle-to-grave analysis, although partial analyses, such as cradle-to-gate analyses may largely follow the same guidelines; deviations for cradle-to-gate analysis are specified. 2.3.3 Part 2a: Guide


Guidelines for Impact assessment are based on so-called mid-point effects: somewhere between total mass loadings and mortality increase (see Part 3, Section 4.2). Furthermore, impacts on the environment are the primary focus in defining impact categories. Thus, energy in MJ is not a category, while depletion of resources (including energy carriers) in certain well-defined terms is one. Guidelines Determine, justify and report the temporal coverage of the study in relation to its goal. This will be a reference point for other choices, e.g., that of the base-period for data collection and the reference period for normalisation. Consider the desired age of the data and the time period over which they have been collected (e.g., one year). Determine, justify and report the geographical coverage of the study in relation to its goal


Determine, justify and report the geographical coverage of the study in relation to its goal. This will also be a reference point for other choices, e.g., the base-area for the choice of system alternatives in a comparison and the reference area for specifying reference flows (performance characteristics). Determine, justify and report the technology coverage of the study, e.g., weighted average of the actual process mix, best available technology or worst-operating unit, in relation to the goal of the study. A baseline choice for the average level of technology currently installed in the specified geographical area (i.e., modal-modern technology) will suffice for many structural, change-oriented decisions. Determine, justify and report the coverage of economic processes (activities) in relation the goal of the study (= initial system boundaries). Determine, justify and report the coverage of environmental interventions in relation to the goal of the study


Determine, justify and report the coverage of environmental interventions in relation to the goal of the study. All relevant emissions and extractions must be included in the study. The researcher can use the list of interventions given in Part 2b, section 4.4, which summarises all interventions covered by the baseline Impact assessment methods (described in Section 4.3.3), as a checklist. The researcher’s level of experience and knowledge of the economic processes concerned and their possible interventions are equally important. Determine, justify and report the coverage of environmental impacts in relation to the goal of the study. All relevant impact categories must be included in the study. The researcher can use the baseline list of impact categories given in Section 4.3.2, which summarises all impact categories covered by the baseline Impact assessment methods (described in Section 4.3.3), as a checklist


The researcher’s level of experience and knowledge of on the economic processes concerned and their possible impacts on the environment are equally important. Interventions and/or impact categories which are deemed important but which are unlikely to be quantified during the analysis should be given a separate status (’flags’). Determine, justify and report whether the mode of analysis (change-oriented, structural decisions) which is the starting point for this Guide is appropriate to the goal of the study. Determine, justify and report the appropriate level of sophistication (simplified, detailed, and possible options for extensions) in relation to the goal of the study and the decision situation at hand. Keep in mind that this choice means choosing a baseline level of sophistication, and that it is always possible to deviate from this choice for specific steps, unit processes, impact categories and so on, provided that such deviations are justified and reported


In the case of a comparison, determine whether it is useful to restrict the LCA to a difference analysis, in which parts of the life cycle that are qualitatively and quantitatively identical (or almost identical) are omitted from the analysis. If it is decided to conduct a difference analysis, justify and report this, along with a list of the life cycle stages and/or unit processes that have been omitted. Part 2a: Guide


The scope of the study should be defined sufficiently comprehensively and in sufficient detail to enable the study to address the stated objectives. Note that LCA is an iterative technique, and not a purely sequential process. This guideline should be kept in mind along the entire LCA process, as the need to revise and reiterate previous steps may arise at any stage. Example (hypothetical) “An LCA is carried out to identify hot spots for the improvement of processes in the Netherlands, so data should be representative of the present state of technology in that country. The study uses the most recent data available, mainly from 1999. The purpose is in agreement with the scope of structural, change-oriented LCA, and simplified guidelines will suffice for most steps. The total size of the study is 8 person-months


The purpose is in agreement with the scope of structural, change-oriented LCA, and simplified guidelines will suffice for most steps. The total size of the study is 8 person-months. A large proportion of this time will be devoted to the collection of representative data of the most important production, recycling and upgrading processes.” Function, functional unit, alternatives and reference flows Topic In this step, the function, functional unit, alternatives and reference flows are defined. The functional unit describes the primary function(s) fulfilled by a product system, and indicates how much of this function is to be considered in the intended LCA study. It will be used as a basis for selecting one or more alternative product systems that might provide these function(s). The functional unit enables different systems to be treated as functionally equivalent and allows reference flows to be determined for each of them


The functional unit enables different systems to be treated as functionally equivalent and allows reference flows to be determined for each of them. For instance, one could define a functional unit for wall painting in terms of the area to be covered, the type of wall, the ability of the paint to cover the underlying surface and its useful life. In a real example, then, the functional unit of a wall covering would be of wall covering with a thermal resistance of K/W, with a coloured surface of 98% opacity, not requiring any other painting for 5 years.” On the basis of the functional unit, a number of alternative product systems can be declared functionally equivalent and reference flows will be determined for these systems. The reference flow is a measure of the outputs from processes in a given product system which are required to fulfil the function expressed by the functional unit


The reference flow is a measure of the outputs from processes in a given product system which are required to fulfil the function expressed by the functional unit. For example, the above functional unit of wall covering might be fulfilled by of wall covered with paint A, and this is therefore the reference flow for the product system that corresponds to paint A. The fact that 10 litres of paint are needed for this purpose is not a part of the goal definition, but rather of the process data (Section 3.3.6). Main choices Functions must be defined as closely as possible to the end-use Depending on the goal and application, the actual, standard or recommended use should guide the definition of the reference flows. Alternatives should be selected on the basis of functional equivalence in the context of the study, but additional considerations may play a role as well. SI units (or SI-derived or SI-based units) must be used to define the functional unit and the reference flows


SI units (or SI-derived or SI-based units) must be used to define the functional unit and the reference flows. 2.3.4 Part 2a: Guide


The size of the functional unit may be chosen arbitrarily (e.g., protecting a 10 square metre wall), or derived from the actual annual size (e.g., protecting 225,000 square metres of wall). The choice of using the actual, standard or recommended performance of products is discussed in section 3.3.6 of the Inventory analysis phase, although most authors, including ISO, discuss it in the context of the present step. Guidelines Guidelines for simplified LCA Follow a stepwise procedure. Step 1: Identify the functions to be analysed, formulating them in terms of the final use function(s) of a specific product system, or from a final need or goal. For cradle-to-gate analyses, identify the functions to be analysed, formulating them in terms of physical output (e.g., covering a floor or producing a certain amount of floor covering material)


For cradle-to-gate analyses, identify the functions to be analysed, formulating them in terms of physical output (e.g., covering a floor or producing a certain amount of floor covering material). Step 2: Determine and describe the function to be analysed or, in the case of more than one function, select the primary function and decide to allocate (see Section 3.3.9) all economic flows and environmental interventions between the primary function and possible additional functions not included in the analysis; or ignore all additional functions and document these ignored functions (e.g., the primary function is that of covering the floor, and the colour and softness have been ignored). Step 3: Define the functional unit. Determine the key parameters for the system’s functioning (e.g., surface to be covered, lifespan of a product, mass etc.) and the units in which they can be expressed; use SI-derived or SI-based units whenever possible (e.g., see Part 2b, Section 2.4)


Define the function of the system in terms of these key parameters as accurately as possible and unambiguously, since this will determine the number of alternative systems that can be considered. Take an arbitrary amount of this function to quantify the amount of function analysed (e.g., Step 4a: Select equivalent alternative product systems meeting the requirements of the functional unit (e.g., carpets, wooden floors). Ensure that the product or service systems selected are consistent with the goal of the study. Justify and explain, if relevant, why certain product or service systems are considered while others have been omitted from the assessment, although they obviously fulfil the same function or service. Describe the consequences of not considering certain functionally comparable systems for the validity of the study's results and conclusions . Make sure that the alternatives selected are real substitutes (see also under step 4b)


Make sure that the alternatives selected are real substitutes (see also under step 4b). If a reference system is to serve as the baseline for comparisons (e.g., to see whether a particular alternative system means an improvement or not, or one for which all results will be put to 1), justify the choice of this reference system in relation to the goal of the study; select the reference system in such a way that the data qualities of the reference system in particular are reasonably consistent in relation to the other systems. 1 From this step on, separate guidelines will be offered for the different levels of sophistication: simplified, detailed and extended, subdivided, where relevant, for various applications. Part 2a: Guide


Document and justify in a transparent manner the “future” assumptions made if the product systems selected include systems that are yet to be developed or do not feature on the current market. Step 4b: Determine the reference flows needed to fulfil the function defined by the functional unit (e.g., of floor covered with carpet, of floor covered with wood), based on standard or recommended use tests. Make sure that the reference flow of every alternative system is a real substitute for the reference flows of the other alternatives (e.g., are we comparing 100 g of steak with 100 g of cutlets or an average portion of steak (100 g) with an average portion of cutlet (150 g)? 1 This step should be done in iteration with the definition of the primary function. Check the function, functional unit, alternative product systems and reference flows that have been selected and defined


Check the function, functional unit, alternative product systems and reference flows that have been selected and defined. Has the function been selected in accordance with the goal(s) defined? Are the units and quantity determined for the functional unit consistent and comprehensive in relation to the goal(s) defined? Functional equivalence: are the product systems selected on the basis of the functional unit really functionally comparable? Report every step that is carried out properly and unambiguously. Give a brief description of the product (or product group) or service studied. Clearly state the relevant function(s) selected as the basis for the LCA study. State any additional functions that have been excluded from the comparison. State the functional unit(s) defined in the proper and unambiguous terms. Justify the product systems selected and describe the main characteristics (trip rate, life span etc...) of these systems. Describe the reference flows properly and unambiguously


Justify the product systems selected and describe the main characteristics (trip rate, life span etc...) of these systems. Describe the reference flows properly and unambiguously. In the case of a comparative assertion, it is mandatory to provide a description of the equivalence of the systems being compared in terms of performance, system boundaries, data quality, allocation procedures, decision rules on evaluating inputs and outputs and Impact assessment, in accordance with ISO 14040, Clause 5.1.2.4. In the case of a comparative assertion, comment on relevant alternatives not covered by the study or list them in the report. If no relevant alternatives exist, it is equally important to state this. Guidelines for detailed LCA and optional extensions Follow a stepwise procedure. Step 1: As for simplified LCA. Step 2: Select the relevant function(s) in relation to the goal of the study


Guidelines for detailed LCA and optional extensions Follow a stepwise procedure. Step 1: As for simplified LCA. Step 2: Select the relevant function(s) in relation to the goal of the study. If there is only one function at stake, use this as the basis for the definition of the functional unit. If various functions are important, the formulation of the functional unit depends on the goal of the study. Formulate a single primary function (e.g., floor covering), preferably by physically separating the functions and allocating (see Section 3.3.9) all economic flows and environmental interventions between the primary function and possible additional functions not included in the analysis; or if functions cannot be separated physically, by selecting the primary function and documenting the omitted other additional functions. Or formulate an integrated function of the system in terms of all important functions (e.g., floor covering that is soft and blue)


Or formulate an integrated function of the system in terms of all important functions (e.g., floor covering that is soft and blue). Step 3: Define the functional unit as in a simplified LCA, except for the following: 1 Observe that the choice of comparing equal portions versus comparing average portions is closely related to the question of choosing actual, standard or recommended performance. This is a choice that has to be made for many (foreground) processes, and is therefore discussed in Section 3.3.6. Part 2a: Guide


Use the actual amount to quantify the amount of function analysed; if not possible, use an arbitrary amount. Step 4a: Select equivalent product systems fulfilling the functional unit as in a simplified LCA. Step 4b: Determine the reference flows. Make sure that the reference flow of every alternative system is a real substitute for the reference flows of the other alternatives. (E.g., are we comparing 100 g of steak with 100 g of cutlets or an average portion of steak (100 g) with an average portion of cutlets (150 g)?) This step should be done in iteration with the definition of the primary or integrated function, especially in multifunction situations. All other guidelines for checks and reporting mentioned for a simplified LCA must also be applied to detailed LCAs and optional extensions. Example (hypothetical) “The function studied in the LCA is that of washing dyed clothes in a household situation


Example (hypothetical) “The function studied in the LCA is that of washing dyed clothes in a household situation. The functional unit has been defined as cleaning 100 kg of dyed clothes in a standard washing machine, in such a way that an independent panel judges the clothes to be sufficiently clean


The functional unit has been defined as cleaning 100 kg of dyed clothes in a standard washing machine, in such a way that an independent panel judges the clothes to be sufficiently clean. The alternatives which are supposed to meet the requirements imposed by the functional unit are: • Clean-em-all at a temperature of • Small-Clean at a temperature of • Cold-Wash at a temperature of The reference flows belonging to these alternatives are: • 20 cycles of the washing machine with the recommended dose of Clean-em-all; • 30 cycles of the washing machine with the recommended dose of Small-Clean; • 20 cycles of the washing machine with the recommended dose of Cold-Clean.” Results of Goal and scope definition The results of the Goal and scope definition phase consist of a clear specification of the goal of the study, the functional unit, and the reference flows for the various alternative product systems. In addition, the scope of the study will guide further choices in subsequent phases


In addition, the scope of the study will guide further choices in subsequent phases. These results form the input for the next phase of the LCA, the Inventory analysis. 2.4 Part 2a: Guide


Inventory analysis Topic Starting points The Inventory analysis is the phase in which the product system (or product systems if there is more than one alternative) is defined. In this context, defining includes setting the system boundaries (between economy and environment, with other product systems, and in relation to cut-off), designing the flow diagrams with unit processes, collecting the data for each of these processes1, performing allocation steps for multifunctional processes and completing the final calculations. Its main result is in an inventory table listing the quantified inputs from and outputs to the environment associated with the functional unit, in terms of kgs of carbon dioxide, mgs of phenol, kgs of iron ore, cubic metres of natural gas, etc. ISO 14040/14041 has been our general starting point for this phase, as it was for the previous Goal and scope definition phase


ISO 14040/14041 has been our general starting point for this phase, as it was for the previous Goal and scope definition phase. As before, the ISO requirements have been made operational through the work of the SETAC LCI group and many individual projects. The inventory steps laid out in this Guide have been copied from ISO 14041, with a few modifications. For a justification and explanation of these adaptations, see Part 3 of this document, Chapter 1. The Inventory analysis phase follows the requirements of ISO 14041, with some additions or further specifications, as described below. Modifications have been made to bring the method in line with the choice of changeoriented, structural decisions. ISO’s preference order for co-product allocation has been further specified, in that a clearer distinction is made between avoiding allocation by more detailed modeling and using real allocation where it cannot be avoided by such modeling


A quality analysis has been shifted to the Interpretation. All additional main methodological choices, including references to all ISO steps, are addressed in the section on main choices; the subsequent sections discuss guideline steps - which sometimes deviate from the ISO steps - for the actual performance of LCA studies. Furthermore, this Guide provides advice on mandatory and optional steps for a number of LCA applications. 1 For the sake of brevity, unit processes are often simply referred to as processes below. In compound terms, the term unit has always been omitted, as for instance in process data and foreground process. Recipe Procedures Economy-environment system boundary Flow diagram Format and data categories Data quality Data collection and relating data to unit processes Data validation Cut-off and data estimation Multifunctionality and allocation Calculation method Page 3. 3.1 3.2 Part 2a: Guide


From the general set-up, some general starting points have been derived for the Inventory analysis phase in this Guide. The underlying model for the Inventory analysis phase in this Guide is based on steady-state equilibrium modeling. This implies, for one thing, that it is primarily to be used to assess the long-term consequences of a decision, i.e., including newly established market equilibriums. The method used in this Guide ignores non-linearities in the relationships between inputs and outputs and flows and effects in industrial and ecologic systems. The method developed ignores details regarding the temporal distribution of activities, emissions, and effects. Emissions are specified as total time-integrated releases, and a similar procedure is used for environmental impacts. At the same time, however, sensitivity analyses allow for finite time horizons, e.g., for landfill processes. The method ignores spatial details as well


At the same time, however, sensitivity analyses allow for finite time horizons, e.g., for landfill processes. The method ignores spatial details as well. For instance, pollutants are assumed to be released to the water, without indicating to which water. Certain site-dependent additions, however, are available. Most economic, socio-cultural and technological mechanisms are either grossly simplified or completely excluded. Recipe Procedures Topic The procedural organisation should ensure identical treatment of all general and specific subjects that the parties involved want to discuss in the Inventory analysis phase


Recipe Procedures Topic The procedural organisation should ensure identical treatment of all general and specific subjects that the parties involved want to discuss in the Inventory analysis phase. Attention should be given to the following issues: normative choices made prior to modeling the product system; the choice of data sources and data quality requirements (possibly validation) to be enforced; enforcement of the accounting rules; choices with respect to the processing of data (for example, scaling) into ‘useful’ specifications; the LCI calculation method, including validation of software programs; researchers and calculations to be used for the purpose of the significance analysis; the type of presentation of the LCI results; possible conclusions based on the LCI results; further process planning and process management. Main choices In the course of this LCA phase, the supervisory process should be arranged so as to preserve the authoritativeness of the results


Main choices In the course of this LCA phase, the supervisory process should be arranged so as to preserve the authoritativeness of the results. The potential input from stakeholders should also be used to improve the quality of the LCA. In this situation of ‘mandated science’, this implies that, depending on the specific process context, there should be room for interaction between the parties involved on topics that are relevant to the definition of system boundaries, cut-off and allocation rules, data quality and so on. 3.3 3.3.1 Part 2a: Guide


Guidelines Guidelines for simplified and detailed LCA and optional extensions Determine the competencies and responsibilities of the LCA research scientists, any critical reviewers, the LCA clients and other interested parties, using Table 3.3.1. Address potential bottlenecks in the LCA process by making arrangements in line with Table 3.3.2 to ensure the orderly progress of the project. Legend Process context I = few diverging interests, potentially strong impact Process context II = many diverging interests, potentially weak impact Process context III = many diverging interests, potentially strong impact C = first LCA client(s) S = stakeholders (including C) L = LCA research scientists R = critical reviewer 1 The actual implementation of all guidelines of this guide should be checked in a critical review. Table 3.3.1 Overview of the competencies of the various actors during the LCA process for the various process contexts


Item Description Process context I II III 1a 1b 2a 2b 3a 3b first instructions with respect to fulfilment of LCA assignment first instructions with respect to fulfilment of assignment of critical reviewer written response to instructions on LCA assignment written response to instructions on assignment of critical reviewer1 possible revision of the first instructions on LCA assignment possible report on incompatible opinions on LCA assignment presentation of draft interim report (= draft text of Inventory analysis) written response to draft report on Inventory analysis possible revision of draft report on Inventory analysis possible report on incompatible opinions arising during the Inventory analysis final opinion on report on Inventory analysis C — L – C L L C L L C C or S C or S L + R R C or S L L + R C or S L + R L C or S S S L + R R S L L + R S L + R L S Part 2a: Guide


Table 3.3.2 Overview of arrangements that can be made between the various different process contexts. Item a b c d e Description widening/supplementation of the study (on request) validation by an independent expert (on request) binding advice on decision points by the critical reviewer final decision-making by the largest possible majority, arbitration, or another previously determined procedure quantification of the influence of incompatible opinions in the final report I o actors for the Process context II r r r r III r r r r r Legend Process context I = few diverging interests, potentially strong impact Process context II = many diverging interests, potentially weak impact Process context III = many diverging interests, potentially strong impact r = recommended o = option Example (case history) In order to develop a sound response to the various lists of environmentally preferable materials, the Dutch building materials sector started the so-called MRPI project in 1996


The umbrella organisation for this sector (NVTB) initiated and co-ordinated the MRPI project with the objective of providing the building sector with “reliable information on environmental aspects of building materials, building products or building elements, delivered at the initiative of the producer or his representative by means of LCA”. Since the interpretation of the LCA output and the use of LCAs to generate environmentally relevant information on products (= MRPI data) turned out to be an important item, the building materials sector is making extensive efforts to educate its members on this issue. The Dutch Concrete Association, for example, developed an LCA training course focusing on the collection and processing of relevant data and the handling of information


The Dutch Concrete Association, for example, developed an LCA training course focusing on the collection and processing of relevant data and the handling of information. This LCA training course characterises the collection of data as the bottleneck ‘pièce de résistance’, necessitating orientation on data concerning processes outside the company, i.e., elsewhere in the product chain. But: ”In practice the suppliers of semi-products and raw materials are a little bit reluctant still when it comes to supplying environmental data. Everybody seems to be afraid of being compared to his competitors. At the same time people in the business chain together have the key in their hands to reach a fundamental break-through in reducing the environmental load.” Nevertheless, the Dutch building materials sector succeeded in implementing the MRPI project; currently, 80 MRPI licences have been issued, in about 20 building sectors


All MRPI data are based on LCAs and all data have been verified by independent organisations. At present (2000) the sector is trying to develop a structural embedding, by providing regular updates to the MRPI data. Part 2a: Guide


Part 2a: Guide Economy-environment system boundary Topic In LCA, each and every flow should be followed until its economic inputs and outputs have all been translated into environmental interventions. The term ‘environmental interventions’ refers to flows entering the product system (for example, natural resources, but also land use) which have been drawn from the environment without prior human transformation, or flows of materials leaving the product system which are discarded into the environment without subsequent human transformation. Environmental interventions are thus flows crossing the boundary between the economy (= product system) and the environment. To create a clear distinction between the product system and the environment and between elementary and other flows, the economy-environment boundary should be explicitly defined. Whenever a system is studied, system boundaries are needed to separate the system from the rest of the world


Whenever a system is studied, system boundaries are needed to separate the system from the rest of the world. An LCA Inventory analysis distinguishes three types of boundaries: the boundary between the product system and the environment system; the boundary between processes that are relevant and irrelevant to the product system (cut-off); the boundary between the product system under consideration and other product systems (allocation). The first of these will be discussed here, while the second is addressed under the heading "Cut-off and data estimation" (Section 3.3.8) and the third under the heading "Multifunctionality and allocation" (Section 3.3.9). Main choices Human control over processes is the main criterion for regarding a process as a unit process and hence including it in the economic system. Guidelines Guidelines for simplified LCA Use the definition of system boundaries that is applied in existing databases and literature sources


Guidelines Guidelines for simplified LCA Use the definition of system boundaries that is applied in existing databases and literature sources. Take note of possible inconsistencies between the various data sources used and of possible deviations from the advice given in this Guide for detailed LCA and optional extensions. Guidelines for detailed LCA and optional extensions Determine the boundary between the product system1 studied and the (natural) environment by applying the definitions for elementary flows (see the Appendix on terms and definitions). In particular: Controlled landfills should be regarded as economic processes from which emissions take place (emissions of organics should be integrated over 200 years, emissions of inorganics like heavy metals ad infinitum); uncontrolled landfills should be regarded as part of the environment system. Partially controlled landfills should be treated as a mixture of these two extremes


Partially controlled landfills should be treated as a mixture of these two extremes. 1 When two or more alternative product systems are being studied, the economy-environment system boundary should be determined for each of these alternatives. 3.3.2


Wastewater treatment should be regarded as an economic process. This implies that releases to a sewage system are not considered as emissions into the environment, but that only the releases of the treated wastewater after sewage treatment is considered as such. Because process data for wastewater treatment are sometimes difficult to obtain, one will in practice sometimes exclude wastewater treatment from the flow diagram. The latter should, however, be clearly reported and justified as a flow that has not been followed to the system boundary. Agriculture and forestry are regarded as economic processes, although agricultural and forestry soils are part of the environment system. Further, the harvested part of a crop should be regarded as a part of the economic system, while the nonharvested part belongs to the environment system


Further, the harvested part of a crop should be regarded as a part of the economic system, while the nonharvested part belongs to the environment system. This means that pesticides on the harvested part of a crop do not show up in the LCA, unless they enter the environment at a later stage, for instance when the crops are washed before cooking and the water used for washing is released to the environment. Treatment of mining tips should be similar to that of landfills. Distinguish, if relevant, between “positive” and “negative” emissions and extractions. Dredging for specific uses (water transport; clay for bricks or dykes) should be included as a negative emission (from the environment), and as a positive emission when it is returned to the environment (particularly to another environmental compartment)


In agriculture, and particularly in forestry, sequestering of in biomass should be regarded as a negative emission, while or released during waste processing of the agricultural product should be considered a positive emission. Justify the reasons for possible deviations from the baseline advice given above. Ensure that system boundaries are defined consistently throughout the LCA study and also beyond the study, with respect to the characterisation factors and normalisation factors used. Check that the economy-environment system boundary defined is consistent with the scope of the study and with these guidelines. In the case of a comparison, check whether the economy-environment system boundary is handled consistently over the various product systems that are being compared. For studies on agricultural products and landfill systems, check whether there are defensible alternative choices with respect to the definition of the economy-environment system boundary


For studies on agricultural products and landfill systems, check whether there are defensible alternative choices with respect to the definition of the economy-environment system boundary. Report the following issues: systems and system boundaries for all stages of the product system life cycle, including inputs, processing routes and spatial and temporal considerations; a justification of the final system boundaries in relation to the goal of the study; inputs and outputs of the system as elementary flows. Example (hypothetical) “In the LCA, agriculture for the production of biofuels has been included in the product system, just like the controlled landfilling of waste. Disposal of sludge into rivers, however, has been categorised as belonging to the environment system. Uptake of carbon dioxide by crops is counted as a negative emission.” Flow diagram Topic The flow diagram provides an outline of all the major unit processes to be modeled, including their interrelationships


It is helpful in understanding and completing a system to describe the system using a process flow diagram. 3.3.3 Part 2a: Guide


Main choices Appropriately constructed flow diagrams are important for understanding the product systems Drafting flow diagrams can be done at different levels of complexity, also in relation to the level of sophistication (detailed, simplified), the most complete being a diagram in terms of unit processes Guidelines Guidelines for simplified LCA For each alternative product system studied, draft an initial flow diagram at the level of aggregated processes for each life cycle stage. Start from the reference flow, the process producing the reference flow and adjacent processes, up to and including the processes producing the main materials and those managing the main waste flows. It is convenient to use boxes for unit processes (or aggregated processes) and arrows for the economic flows linking them


It is convenient to use boxes for unit processes (or aggregated processes) and arrows for the economic flows linking them. Environmental interventions are often omitted from the flow diagram, because the main function of the flow diagram is to illustrate the structure of the product system and the relationships between the unit processes. Text labels in boxes should clearly indicate the names of the unit processes, and text labels attached to arrows show the names of the economic flows. Use arrows primarily to indicate the physical direction of flows. For instance, use an arrow from consumption to waste treatment to indicate the flow of disposed products, and not the other way around to indicate the flow of the waste treatment service. However, it is often more convenient to indicate service-providing activities in a different way. Thus, a cleaning process does not absorb dirt, but provides a cleaning service


However, it is often more convenient to indicate service-providing activities in a different way. Thus, a cleaning process does not absorb dirt, but provides a cleaning service. Indicate clearly which of the boxes refers to a unit process and which to a partial flow diagram with aggregated unit processes. Guidelines for detailed LCA and optional extensions These are the same as for a simplified LCA, but with the following additional guidelines. Draft a detailed flow diagram in iteration with the data collection step (see Section 3.3.6), starting from the initial flow diagram. Solve the problem of huge numbers of unit processes and complex interrelationships by zooming in from the initial flow diagram to the underlying unit processes in partial flow diagrams


Solve the problem of huge numbers of unit processes and complex interrelationships by zooming in from the initial flow diagram to the underlying unit processes in partial flow diagrams. Check whether the number of flows for which estimated data must be collected in relation to the number of flows for which specific data have been collected is consistent with the goal(s) and scope of the study and the guidelines given. Check whether the flow diagram is complete. In the case of a comparison, check whether there are any inconsistencies between the flow diagrams of the systems being compared. Report process flow diagrams describing the complete system under study. Include system boundaries, major inputs, products and co-products in the process flow diagrams. The process flow diagrams should include the main production sequence, ancillary materials and energy/fuel production. Part 2a: Guide


Example (hypothetical) Part 2a: Guide “The flow diagram for the investigated system of PE disposable bags is visualised below. The environmental inflows and outflows have been omitted for the sake of readability.


Format and data categories Topic A key task of the Inventory phase is the collection of process data. This usually involves large quantities of data in electronic form, retrieved in part from databases set up by others. To render these comparable and mutually consistent, a standard data format must be developed. All the various data categories should be assigned a specific place in this format and a general description given of each to facilitate and guide data entry and retrieval. Main choices Choice of data categories should be made in relation to the impact categories and characterisation factors included. Using a transparent format is important. Conformity with a data exchange standard is important. The so-called SPOLD format provides such a standard. Adaptations of this standard may be required in relation to choices made in other steps, like terminology and definitions of data categories


The so-called SPOLD format provides such a standard. Adaptations of this standard may be required in relation to choices made in other steps, like terminology and definitions of data categories. Guidelines Guidelines for simplified and detailed LCA and optional extensions Use the SPOLD format as much as possible for the collection of data for foreground processes; for background processes, use the format applied in the database or literature source used for data on these background processes, or if possible, convert these data to the SPOLD format too. See Part 2b, Section 3.4 for references to further information. Use the headings of the SPOLD format as the main data categories. However, adaptations are needed; see Part 2b, Section 3.4 for a list of data categories. Treat energy inputs and outputs like any other economic input and output to an LCA


However, adaptations are needed; see Part 2b, Section 3.4 for a list of data categories. Treat energy inputs and outputs like any other economic input and output to an LCA. Use the list of elementary flows for which Impact assessment data are available (see Part 2b, Section 4.3) as a reference list to specify these main data categories. Use the CAS number where possible and relevant. Distinguish emission compartments, where relevant, into air; fresh water; seawater; agricultural soil; industrial soil. In addition to the reference list provided above, include data on some more relevant inventory items. Depending on the goal and scope of the study and on the choice of impact categories, inventory items of interest may be: land occupation; land transformation; emissions of waste heat; casualties; sound. Report decisions about data categories and details about individual data categories. 3.3.4 Part 2a: Guide


Example (hypothetical) No example. Data quality Topic For LCA models, like any other model, it holds that “garbage in = garbage out”. In other words, data quality has a major influence on results, and proper evaluation of data quality is therefore an important step in every LCA. Even if the quality of individual datasets is high, however, such data can still yield erroneous results if used to answer questions on which they have limited or no bearing. The data used in a given case study should, for instance, be representative of that particular study. Quality requirements thus refer to both the reliability and the validity of process data. Since validity depends on the application in question, it is not validity requirements as such that are specified here but the data needed to assess that validity


Since validity depends on the application in question, it is not validity requirements as such that are specified here but the data needed to assess that validity. Main choices Since fully operational models for assessing the influence of data quality on output validity are lacking, a partial qualitative data quality assessment is provisionally proposed, based on suggestions from ISO 14041. Although a full quantitative assessment of every dataset is not feasible, one should not neglect to include quantitative data quality information (meta-data) for those items for which this is available


Guidelines Guidelines for simplified and detailed LCA Data quality should be specified in terms of: collection from specific sites versus general data; being measured, calculated or estimated; precision, as a measure of the variability of the data values for each data category expressed (e.g., variance); completeness, as a percentage of locations reporting primary data from the potential number in existence for each data category in a unit process; representativeness, as a qualitative assessment of the degree to which the dataset reflects the true population of interest (i.e., geographical, time period and technology coverage); consistency, as a qualitative assessment of the degree of uniformity with which the study methodology is applied to the study serving as the data source; reproducibility, as a qualitative assessment of the extent to which information about the methodology and data values allows an independent practitioner to reproduce the results reported in the study serving


as a qualitative assessment of the extent to which information about the methodology and data values allows an independent practitioner to reproduce the results reported in the study serving as the data source; justification of the choice of data sources selected in relation to the goal of the study and particularly to scope issues such as temporal, geographical and technology coverage; reliability of different data sources in qualitative terms; completeness of the data provided (for instance, if there are unreported emissions); correctness of the mass and energy balances; agreement between the data sources used and other data sources


3.3.5 Part 2a: Guide


If possible, ask for opinions of technical (non-LCA) experts. If a comparison is being made, check whether: the data quality requirements and the choice between marginal and average data are consistently elaborated between the product systems compared; there are any major differences between the product systems being compared, with respect to the ratio between background and foreground data; the estimated importance of the flows for which specific data are lacking differs considerably between the various systems being compared. In the case of a comparative assertion, report on the assessment of the precision, completeness and representativeness of the data used. Justify and report maximum baseline data quality requirements. The report must clearly establish and define data quality goals, as well as any variability of data considered in the study. Identify clearly all data sources for the study and reference them


The report must clearly establish and define data quality goals, as well as any variability of data considered in the study. Identify clearly all data sources for the study and reference them. Key indicators of data quality should be reported, so that choices are justified and transparent, including: age of data; frequency of collection; spatial and temporal considerations; any other relevant factors. The quality assessments may be reported as a Pedigree Matrix per process (see Part 2b, Section 3.5). If data are presented in aggregate form (e.g., for reasons of confidentiality), is the aggregation procedure fully described? A sensitivity analysis of key data sets should be included. Guidelines for optional extensions All guidelines provided above for simplified and detailed LCA apply here. Consider developing a new method for data quality assessment. If so, document and justify comprehensively and transparently the method developed and the choices and assumptions made


Consider developing a new method for data quality assessment. If so, document and justify comprehensively and transparently the method developed and the choices and assumptions made. Example (hypothetical) See example under Section 3.3.6. 3.3.6 Data collection and relating data to unit processes Topic This step of the Inventory analysis phase involves the collection of all relevant data on the unit processes and quantifying all flows connected to the unit processes in accordance with the format specified above (Section 3.3.4). The reference flow(s) (see Section 2.3.4) defined in the Goal and scope definition phase of the study form(s) the starting point for data collection. The process data available to the practitioner may be structured in any number of ways. In LCA databases, process data are often organised around unit processes, relating a given economic output to economic inputs and environmental inputs and outputs


In LCA databases, process data are often organised around unit processes, relating a given economic output to economic inputs and environmental inputs and outputs. Process data provided by companies are often also organised around unit processes, but given in terms of inputs and outputs per unit of time, e.g., emission of 5 tonnes of per year, input of 1000 tonnes of wood per year, etc. In existing LCA databases, process data are almost always quantified in relation to some physical (reference) flow (e.g., one kg of material or 1 MJ of electricity). Part 2a: Guide


Main choices The ISO step labeled "Relating data to unit processes" has been integrated with ISO’s "Data collection" step, since the activity of relating data to unit processes has too little substance to make it a separate element, and since it is inextricably linked with the activity of data collection. If possible, conversion of the data should be minimised and, if necessary, clearly documented. A distinction will be made between foreground and background processes, although various definitions of these terms are in use, and an unambiguous partitioning of processes into these two sets may be impossible. In this Guide, foreground processes are those unit processes for which case-specific primary data are used, while background processes are those unit processes for which more general information is used. Guidelines Guidelines for simplified LCA Determine a small number of foreground processes, i.e., processes for which primary data will be collected


Guidelines Guidelines for simplified LCA Determine a small number of foreground processes, i.e., processes for which primary data will be collected. The remainder of processes are treated as background processes for which secondary data sources, such as generic databases, literature or IOA data (see Section 3.3.8 on data estimation) may be used. With respect to data collection for foreground processes, the following guidelines apply. Collect process data, preferably in flow-per-time figures, and relate the data to one of the flows through scaling factors, using time as a dimension, if the software allows for this (see Section 3.3.10 on calculation method). SI units (or SI-derived or SI-based units) should be used wherever possible in collecting data for all economic and environmental flows. For suggested units in the various data categories, see Part 2b, Section 2.4. Consider to what extent market mixes should form the basis for the data on a particular unit process


For suggested units in the various data categories, see Part 2b, Section 2.4. Consider to what extent market mixes should form the basis for the data on a particular unit process. For instance, a study on bottles for the European market will probably involve many bottle producers, so that a market mix, proportional to the market shares, is more representative than a choice of one particular bottle producer. If a market mix is to be used, the average level of currently installed technology in the relevant geographical area (i.e., modal vs. modern technology) will in many cases be a good choice. Justify and document procedures used for data collection. Describe each of the unit processes initially to define where the unit process begins (in terms of the receipt of raw materials or intermediate products and the nature of the transformations and operations that occur as part of the unit process) and where it ends (in terms of the destinations of the intermediate or final products)


For the unit process from which the reference flow emanates (usually the use process), determine whether actual, standard or recommended performance is the best option in relation to the goal of the study. Consider whether this choice is also relevant to other foreground processes. For these processes: if geographical context is relevant, adapt standard or recommended use to the specific geographical circumstances; if temporal context is relevant, adapt standard or recommended use to the specific temporal circumstances; check whether the options that are being compared have the same performance; present the result of a performance measurement. With respect to data collection of background processes, the following guidelines apply. Where data are collected from published literature, specify the source. Part 2a: Guide


The practitioner must realise that the choice of secondary data sources may significantly influence the outcome of the study and limits the opportunities for choosing different allocation rules or cut-off criteria and conducting sensitivity and uncertainty analyses. The practitioner must explicitly justify that the data source(s) selected for the background processes are representative with respect to the specification of the goal and scope of the study. A list showing a number of commonly used databases with process data is included in Part 2b, Section 3.6. Avoid the use of group parameters (such as CxHy, PAH, heavy metals, AOX) as much as possible1. If some process emissions are specified as a group parameter: split up the group parameter into its individual chemical constituents; convert the group parameter using generic conversion factors like those included in Part 2b, Section 3.6; if this is not possible, report original data, conversion methods and converted data


For those emissions for which the characterisation tables in Part 2b, Section 4.3 require this, specify, where possible, the emission compartment: air; water, divided for certain substances into fresh water and seawater; soil, divided for certain substances into agricultural soil and industrial soil. If such a specification is not known, assign the emissions to the most plausible emission compartment, and report what has been done. Some example guidelines include the following. Emissions of volatile substances can be assigned to the air compartment. Emissions of substances to water can be assigned to the freshwater compartment. Emissions of pesticides and fertilizers to the soil can be assigned to the agricultural soil compartment. Emissions of industrial processes to the soil can be assigned to the industrial soil compartment. Interventions that are not assigned to any impact category or that lack appropriate characterisation factors should not be omitted from the Inventory analysis


Interventions that are not assigned to any impact category or that lack appropriate characterisation factors should not be omitted from the Inventory analysis. The use of data from pre-allocated databases is to be restricted to simplified LCA. Guidelines for detailed LCA and optional extensions All guidelines provided above for simplified studies also apply here, except for the first. The first guideline, stating that data must be obtained for a small number of foreground processes, is replaced by the following guideline: determine a large number of foreground processes, i.e., processes for which primary data will be collected. In addition, the following guidelines apply for detailed and extended studies: Assess all primary data collected by the data quality requirements defined in Section 3.3.5. Whenever possible (e.g., in the case of consumer products), determine the data for the unit process from which the reference flow emanates (usually the use process)


Whenever possible (e.g., in the case of consumer products), determine the data for the unit process from which the reference flow emanates (usually the use process). Based on the relevant performance test, the following hierarchy of preference can be used: actual use, e.g., based on behaviour surveys, consumer enquiries or market studies; standard use in combination with consumer behaviour studies; recommended use in combination with consumer behaviour studies. Specify all secondary data collected from databases, literature, etc., as well as the published literature which supplies details about the relevant data collection process, about the time when data have been collected and about further data quality indicators. Perform this step in iteration with the contribution and perturbation analyses (see Sections 5.3.4 and 5.3.5). 1 Note: group parameters are only legitimate parameters if measured as such, not if calculated from measurements of individual chemicals. Part 2a: Guide


Include estimated process data (see Section 3.3.8), and indicate these as such. Include details of the calculation procedure used for the energy systems in the report. In particular, specify whether country-specific or average energy has been used for materials and processing, the use of high or low calorific values, the approach used for feedstock energy and the conversion of electricity into primary energy. Try to avoid the use of data from pre-allocated databases. Example (hypothetical) “The table below presents the production


Try to avoid the use of data from pre-allocated databases. Example (hypothetical) “The table below presents the production. Item general information name code author date source status precision temporal representativeness geographical representativeness economic outputs ethylene economic inputs naphtha emissions to air benzene ethylene emissions to fresh water benzene cadmium phenol fictitious process data for Value production of ethylene Z-23-4f CML 14 May 2001 Jones (2000): The Handbook based on average of representative plants the unit process of ethylene of Life Cycle Data measurements from not specified, but there seems to be little variation across the individual plants mid-nineties average for Western Europe 950kg 1000kg 3.3.7 Data validation Topic This step involves checking the validity of the process data collected


Various tools are available for this purpose, including mass balances, energy balances and comparison with data from other sources (e.g., comparative analysis of emission factors). Any data found to be inadequate during the validation process should be replaced. Similarly, missing data should be identified in this step and a decision made on how these gaps are to be filled. Main choices Not applicable. Part 2a: Guide


Guidelines Guidelines for simplified LCA Validate data collected for the foreground processes, and for all background processes significant for the conclusions of the study, by establishing mass and energy balances and by comparative analysis of the different data sources used. A contribution analysis (see Section 5.3.4) can be used to point out this class of data. Address missing data and gaps in the foreground data and significant background data by means of one of the following: a non-zero data value which is justified; a zero data value, if justified; a calculated value based on values reported for similar technology, or another type of estimate (see the Section 3.3.8 on data estimation). Document and justify the criteria used for determining the “correct” data values from such validation procedures. Guidelines for detailed LCA and optional extensions In addition to the above guidelines for simplified LCA, the following also apply


Guidelines for detailed LCA and optional extensions In addition to the above guidelines for simplified LCA, the following also apply. Report anomalies in foreground data, and wherever possible also in significant background data, to the reporting location (i.e., internal company experts) or reporting source to determine their validity. Obvious anomalies in the data appearing from such validation procedures must result in alternative data values, which comply with the data quality requirements established in Section 3.3.5. Example (hypothetical) No example. 3.3.8 Cut-off and data estimation Topic In principle, an LCA should track all the processes in the life cycle of a given product system, from the cradle to the grave. In practice this is impossible, however, and a number of flows1 must be either roughly estimated or cut off2 and subsequently ignored


In practice this is impossible, however, and a number of flows1 must be either roughly estimated or cut off2 and subsequently ignored. The root problem behind the cut-off issue is the lack of readily accessible data, implying disproportionate expenditure of funds and effort on data collection. Cut-off can substantially influence the outcome of an LCA study, however, which means that ‘easy’ LCAs come at a price. The cut-off problem can be formulated as a problem of having to quantitatively estimate the environmental interventions associated with flows for which no readily accessible data are available. Main choices Cut-off is necessary mainly for reasons of lack of data, in combination with lack of time and money. The problem comes up after data collection, when it turns out that production processes for some inflows and waste treatment processes for some outflows are unknown or undocumented