Use-phase related impacts that these products exert via an emission to the ecosphere (e.g. smoke emissions to the environment, wastewater-discharge) are however to be included. Equally, not explicitly addressed are impacts that occur directly within the technosphere (e.g. workplace exposure)70. In summary, accidents, social and other work environment aspects including workplace-exposure, and indoor-emissions are not normally covered by LCA (and not addressed in this guidance). If included they must be inventoried, aggregated and interpreted separately from the life cycle inventory that relates to inventions between the technosphere and the ecosphere and related to normal operation of the involved processes. Limited guidance in ISO on types of processes to include in attributional modelling In ISO this step is only addressed implicitly for attributional modelling; no clear guidance is given which activities or processes actually relate to the analysed system


While it is generally agreed that extraction and direct processing of a material that ends up in the analysed good is part of the system, the general inclusion of investment goods, administration activities, marketing services, staff commuting, etc. is done differently by different practitioners. In any case depends the setting of the system boundaries on the LCI modelling framework: in case of attributional modelling the system is modelled as it is, following a existing or forecasted, specific or averaged supply-chain logic. In consequential modelling, in contrast, the consequences that the analysed system exerts on other systems are modelled, why these are the processes of a theoretically modelled supply-chain are to be included in the system boundaries. For consequential modelling, the informative ISO/TR 14049 gives illustrative guidance on the identification of these processes. This serves as starting point for updated and further detailed guidance; see chapter 7.2.4

European Commission – JRC, ILCD Handbook: General Guide for LCA (2010)


This serves as starting point for updated and further detailed guidance; see chapter 7.2.4. 69 Accidents and accident-type leakages and spills shall not be inventoried as part of the normal life cycle inventory since they are fundamentally different in nature from the production or operation related normal and abnormal operating conditions that LCA relates to (OTHER than e.g. fugitive emissions through sealings and other “engineered losses” that are included in LCA). Accident modelling necessarily requires dealing with frequencies and with cause-effect chains (to assign them to the causing unit processes). Work on this Life Cycle Accident Assessment is still under methodological development, while a number of explorative case-studies have been published. 70 Methods to capture work-place exposure and other social work-place aspects are in between more advanced under the Life Cycle Working Environment approach, while still lack broader application in practice


Methodological work on indoor-exposure in private households is equally ongoing. It is unclear and widely discussed whether both these types of impacts inside the technosphere belong under “environmental impacts” or should be addressed separately, while within the same life cycle analysis frame. Within this ILCD guidance they are not addressed for the time being until methods have been advanced and more practice experience has been gained.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how On a higher level, widely different practices are found in relation to a systematic inclusion or exclusion of accidents, the direct ingestion of food, application of e.g. cosmetics to the skin, indoor exposure at workplace and home, etc. The basic guidance for the question which activities at all are to be related to a product or process are given in the LCI work chapters 7.2.3 and 7.2.4, separately for attributional and consequential modelling, respectively. This question is to be answered early in the scope phase as one basis for identifying principle data needs. The identification of the specific processes takes then place in the LCI phase of the LCA


This question is to be answered early in the scope phase as one basis for identifying principle data needs. The identification of the specific processes takes then place in the LCI phase of the LCA. System boundaries of unit process data sets For unit process data sets and regarding product and waste flows, the system boundary is the boundary between the modelled process and the rest of the technosphere. I.e. all product and waste flows that enter or leave the process cross the boundary and hence appear in its inventory. Also all the elementary flows that directly leave the process towards the ecosphere or directly enter from there cross the system boundary are to be inventoried. System boundaries of LCI results, LCIA results, and LCA studies For LCI result and LCIA result data sets and for full LCAs, the system boundaries should ideally be set in a way that all flows crossing the boundaries are exclusively elementary flows plus the reference (product) flow(s)


In other words: all71 other product and waste inputs and outputs should be completely modelled until the final inventories exclusively show elementary flows. Figure 12 Cradle to grave, cradle to gate and gate to gate data sets as parts of the complete life cycle; schematic. Each type fulfils a specific function as module for use in other LCA studies. Terms and concepts: Foreground system and background system The analysed system is typically differentiated into the processes of the foreground system and those of the background system. Two different purposes are behind this differentiation that lead to two different concepts and usages, however: The first is the purpose of identifying where specific data should be used versus where average or generic background data can typically be used by default ("specificity perspective")


The second is the purpose of identifying which processes can be managed by direct control or decisive influence from the point of view of the decision-context of a study ("management perspective"). In context of this 71 Note that exclusively for partly terminated systems selected product and/or waste flows may stay in the inventory; the life cycle data of these are then completed by the user of the data set. Company B Company C Company A End-of-life managament Extraction Material and part production Assembly Retail Gate to gate Cradle to gate (B) Cradle to grave Use


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how guidance and for the purpose of data collection and compilation, the definition related to the "specificity perspective" is applied. Note that the specificity perspective related distinction is only indicative, as key is the accuracy, precision and completeness of the data - especially generic data can for a given case be more suitable for the foreground system (see also chapter 7.4.2.5). Note that also for the management perspective related distinction many processes cannot be clearly assigned to either foreground or background, as they can only be partially influenced. Specificity perspective Definition foreground system: In context of the "specificity perspective", the foreground system is defined as those processes of the system that are specific to it. This means that data for the specific e.g. technology, supplier etc. is most appropriate


This means that data for the specific e.g. technology, supplier etc. is most appropriate. These are in the example of a study on a producer-specific product the processes that are operated at the producer's facilities, but also all those processes at suppliers and downstream where only one or few operators are involved, i.e. where the specific processes cannot be replaced by e.g. market average supply data. These are hence typically the tier-one suppliers, but also suppliers more up the supply-chain, if specific relations exist, e.g. by using certified green energy or certified wood sources and the like. Definition background system: The background system is then those processes, where due to the averaging effect across the suppliers, a homogenous market with average (or equivalent, generic data) can be assumed to appropriately represent the respective process


Use stage and end-of-life stage related processes belong hence to the background system from the perspective of the producer, in so far as the average use and end-of-life management processes are to be depicted. However, the specific characteristics of the product that is used and end-of-life treated are to be considered, hence combining specific properties with average/generic processes. Moreover, in case specific scenarios of use or end-of-life treatment technologies are investigated, these become part of the foreground system of the analysis and specific data is preferable. Management perspective Definition foreground system: In context of the "management perspective", the foreground system is defined as those processes of the system that are regarding their selection or mode of operation directly affected by decisions analysed in the study


The foreground processes are hence those that are under direct control of the producer of the good or operator of the service or user of the good or where he has decisive influence. This variant of the foreground / background definitions is relevant for ecodesign studies. This covers firstly all in-house processes of the producer or service operator of the analysed system. Secondly, while only for attributional modelling72, also all processes at suppliers of purchased made-toorder goods and services, i.e. as far as the producer or service operator of the analysed 72 Consequential modelling has no logic to depict existing supply-chains but models future supply-chains in consequence of the analysed decision (considering ideally constraints and secondary consequences): not the supplier-specific processes would be modelled but the general marginal / consequential processes, which at the most may consider certain supplier-characteristics (e.g


with which technology and in which country the supplier produces). It can even be in consequential modelling that processes under direct control of the producer or operator belong to the background system: That is if a specific decision is made that has consequences on other processes under direct control that are not directly decided upon but only via the consequence of the specific decision. That is unless a constraint applies that makes it unlikely that the concerned process is actually changed from its current technology in consequence of the analysed decision.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how system can influence them by choice or specification73. Thirdly also all product and waste flows that cross the system internal boundary to the background system can be decided upon, as it can be decided which goods or services are purchased, even though the way how they are produced can be beyond this influence. Next, the use-phase is considered part of the foreground system from the perspective of the product developer in so far as the developer strongly influences the design-related use stage characteristics. Note that this influence exists, even though e.g. wholesale and retail may be processes in between production and use, and even though the use pattern influences the final inventory. Finally, also some key aspects of the end-of-life management of the product are part of the foreground system, as far as design-related properties (e.g


Finally, also some key aspects of the end-of-life management of the product are part of the foreground system, as far as design-related properties (e.g. upgradability, reusability, disassembility / recyclability, etc.) influence these processes. For attributional studies build around the use stage of consumer products, the foreground system would accordingly be the product use and the selection of the initial waste management (if the user has a choice of different options). Definition background system: In contrast, the background system comprises those processes that are operated as part of the system but that are not under direct control or decisive influence of the producer of the good (or operator of the service, or user of the good). For attributional modelling these are typically processes at tier-two suppliers and beyond, both upstream and downstream the supply-chain


For attributional modelling these are typically processes at tier-two suppliers and beyond, both upstream and downstream the supply-chain. Examples are steel production for steel parts purchased by a manufacturer of computer-casings, or the production of the electricity used by a tier-one supplier of injection moulded plastic parts. The background processes and systems are hence outside the direct influence or choice of the producer or service operator of the analysed system. This includes hence processes at those tier-one suppliers with which long-term contractual relations exist and which hence cannot be changed. For consequential modelling the background system comprises everything except processes at the producer / operator and those tier-one suppliers with which long-term contractual relations exist and which hence cannot be changed. The foreground and background system interact with each other directly by exchanging goods or services


The foreground and background system interact with each other directly by exchanging goods or services. In a simple picture, the background system in attributional modelling of a certain market and moment in time (typically year) is the weighed average mix of the economy of that market and time into which the analysed system is embedded (and to which different processes it has quantitatively more or less relevant links via demand and supply). In consequential modelling the background system of a certain market and moment in time can be understood as the weighed future shift of the economy of that market at that moment or time-period (e.g. year ... decade), i.e. it is the quantitative mix of the newly installed and de-installed capacity of that market and during that time. Figure 13 systematically illustrates the foreground and background system and the general system boundaries as well as the flows within and those that that cross them. 73 I.e


Figure 13 systematically illustrates the foreground and background system and the general system boundaries as well as the flows within and those that that cross them. 73 I.e. this can also includes external waste management services purchased, as far as the product system producer/operator can choose the way the waste is managed (within technical and legal limits).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Figure 13 Foreground system and background system in the specificity perspective (see box); (illustrative): The analysed system has boundaries (dashed border), separating it from the remainder of the technosphere and from the ecosphere. The system may be divided into the foreground system of processes that are specific to the analysed system i.e. own operations and fixed suppliers. The processes in the background system are not specific but purchased via a (theoretically fully homogenous) market. The system is the exact sum of the background and the foreground systems. Quantitatively irrelevant flows can be excluded, i.e. cut-off (dotted arrows).74 Completeness / cut-off In reality however, even for simple products, all economic activities globally are somehow part of the system


cut-off (dotted arrows).74 Completeness / cut-off In reality however, even for simple products, all economic activities globally are somehow part of the system. However, the number of processes that contribute in a quantitatively relevant degree to the system is typically rather limited, why this theoretical problem has little relevance in practice: In practice, all quantitatively not relevant non-reference product flows, waste flows, and elementary flows can be ignored - they are 'cut-off'75. Care must be taken that not more flows and related impacts are cut-off than acceptable to still meet the goal of e.g. a comparative study. Respectively, that the data sets that are used to model a system do meet this need of completeness. Chapter 6.6.3 provides further details on cut-offs. Loops In addition, for system models virtually eternal loops exist: The production of e.g


Chapter 6.6.3 provides further details on cut-offs. Loops In addition, for system models virtually eternal loops exist: The production of e.g. steel requires coal, the extraction of which requires equipment made from steel, the production of which requires again coal, etc. These loops can be solved by LCA software either 74 As the example shows a complete life cycle the system function is not shown; otherwise it would be represented by one flow that would leave from the last process step and cross the boundary to the rest of the technosphere. Note that the graphic is only illustrative and by no means complete. Also does the background system almost always contain a by far larger number of processes than does the foreground system. 75 Note that this „incompleteness“ of the inventory is fully acceptable and has no consequences on the validity of the LCA, as the extent of the incompleteness (i.e. the quantitative cut-off criteria) are set in line with the goal and scope of the study


the quantitative cut-off criteria) are set in line with the goal and scope of the study. Ecosphere Technosphere Upstream Downstream Legend: Process Product or waste flow Elementary flow Excluded product or waste flow Excluded elementary flow Allocation / Substitution System (e.g. product) Background system Foreground system A/S A/S


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how mathematically or by iterative calculation of the inventories, which can be assumed to show a fast conversion of the values to stable numbers. Towards an systematic qualitative and quantitative definition of the system boundaries Setting the system boundaries means deciding which life cycle stages, activity types, specific processes, and elementary flows to include and which to omit from the life cycle model. This has two aspects: A qualitative definition of what is needed to obtain the functional unit of the system and the setting of quantitative cut-off rules. Both are to be derived from the goal of the LCI/LCA study. The following subchapters explain these steps


Both are to be derived from the goal of the LCI/LCA study. The following subchapters explain these steps. 6.6.2 Qualitative definition of system boundaries (Refers to ISO 14044:2006 chapter 4.2.3.3.2) Goal-oriented qualitative definition of the system boundaries The qualitative definition of the system boundaries shall identify those parts of the life cycle that are to be included to provide e.g. the required data set or to ensure a valid comparison in case of comparative studies. E.g. in the comparative assertion on two different production routes to obtain “1 kg polyamide 6.6”, a cradle-to-gate model would be appropriate, leaving out other stages of the two compared systems (provided that the technical quality, including recyclability, of the two resulting products does not differ significantly). In contrast, in the comparative assertion on e.g. “1 l one-way PET bottles” vs. “1 l one-way glass bottles”, both “..


In contrast, in the comparative assertion on e.g. “1 l one-way PET bottles” vs. “1 l one-way glass bottles”, both “... for still water packaging for end-consumer storage and consumption”, also the transport of the bottles to the consumer would have to be considered as well as their end-of-life management (i.e. recycling or other treatment of the post-use bottles). A comparison of the bottles that would only cover cradle-to-gate would here hence be invalid as incompletely reflecting the different life cycle implications of the two alternatives: they have different transport implications and different end-of-life management that need to be included for valid decision support. System boundaries - attributional vs. consequential modelling In attributional modelling the life cycle of the system is modelled as it is, following a general supply-chain logic (plus use and end-of-life treatment in case of a product, if these are to be included)


The principle system boundaries and included life cycle stages can be derived from the goal and scope of the work. The specific processes are developed stepwise starting from the foreground system and following the process-chain and supply-chain as well as use-stage stepwise upstream and downstream (details see chapter 7.2.3). In consequential modelling, in contrast, the consequences that the decisions on the foreground system's processes of the analysed system exerts on its background system and/or other systems are modelled. In consequence, processes of other systems than the one analysed are to be included in the system boundary of the analysed system. The system boundaries of an identical product can differ hence strongly between these two approaches. Exceptions are only the processes under direct control of the producer/operator


The system boundaries of an identical product can differ hence strongly between these two approaches. Exceptions are only the processes under direct control of the producer/operator. System boundary diagram The system boundary shall be represented in a semi-schematic diagram that explicitly shows which parts and life cycle stages of the system are initially intended to be included and excluded. Note that in case of partly terminated systems, selected processes are deliberately foreseen to be excluded from the system boundary. The corresponding product and/or waste


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how flows are meant to stay in the final inventory after aggregation, i.e. cross the system boundary in the provided data set76. This shall be shown in the system boundary diagram. This initial diagram is to be adjusted in case goal and scope need to be adjusted in the course of the project. A schematic recommended system boundary diagram template is provided as Figure 35 in the annex. It is recommended to prepare a technical flow chart for the foreground system. This flow chart should show the main process steps (see example in Figure 14). It can later be refined when carrying out the data collection. Figure 14 Flow chart of the foreground system. Illustrate example of a form glass gate-togate process chain. In order to have general overview, only the main processing steps are shown; this does not imply data for other activities would be excluded


In order to have general overview, only the main processing steps are shown; this does not imply data for other activities would be excluded. Part-system relationships LCI or LCA studies on parts or even complex products that are part of a more complex system (e.g. different car starter battery technologies; use of a water-saving shower head; different window frame concepts/materials) need special attention: the technical interaction between the analysed part and the system and its other parts is to be explicitly considered in the system boundary definition. Parts that are operating in context of a larger system can typically not be analysed in isolation, especially not be compared with other parts that interact with the system in another way. This applies to both attributional and consequential modelling. The related box in chapter 7.2.2 provides more information on this issue


This applies to both attributional and consequential modelling. The related box in chapter 7.2.2 provides more information on this issue. System-system relationships Similar as for part-system relationships also studies on systems that change the operation of other context systems (e.g. computers or coffee-machines that generate heat and change the operation of the heating and/or cooling system of the building in which they are operated) need to consider this interrelationship. The topic system-system relationship applies to both attributional and consequential modelling. The related box in chapter 7.2.2 provides more information. Systematic exclusion of activity types A systematic exclusion of e.g. transport, infrastructure, services, administration activities, etc. is not appropriate unless necessary according to the specific goal of the LCI/LCA study (e.g


transport, infrastructure, services, administration activities, etc. is not appropriate unless necessary according to the specific goal of the LCI/LCA study (e.g. if the quantitative relevance of such activity types is to be analysed, the system would 76 When later using the data set in another system, the system model has to be completed also for these product and waste flows, of course. Melting furnace Glass forming Annealing Inspection & Testing Cullet crushing Packing Storage or shipping


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how be modelled twice, once with and once without them): in principle all quantitatively relevant activities that can be attributed to a system (or are result of the consequences, in case of consequential modelling) should be included in the system boundaries unless they are quantitatively irrelevant, applying the cut-off criteria (see next subchapter). The need for inclusion and the possibility of exclusion of activities can only be decided for the given case in view of the required completeness and precision of the results. Types of activities that are generally to be included cover for example mining, processing, manufacturing, use, repair and maintenance, transport, waste treatment and other purchased services such as e.g


cleaning and legal services, marketing, production and decommissioning of capital goods, operation of premises such as retail, storage, administration offices, etc. An initial exclusion of activities can be justified, carefully and individually based on experience gained for comparable systems. Reduced accuracy and limitations for conclusions and recommendations are otherwise the consequence. A systematic approach for identifying activities and processes that are to be attributed to a system is given in the LCI work chapter – see chapter 7.2.3 for attributional modelling and chapter 7.2.4 for consequential modelling Emission off-setting Off-set emissions (e.g. due to carbon off-setting by the Clean Development Mechanism, carbon credits, and other system-external off-sets) are not to be included in the system boundaries and the related (reduced) emissions are not to be integrated into the inventory or used in LCA results interpretation. Note that e.g


Note that e.g. carbon capture and storage and other means that are part of the analysed systems are to be included; these must not be confused with off-setting measures that are always external to the analysed system. Such information can only be reported as additional environmental information as may be foreseen e.g. in Environmental Product Declarations (EPD). 6.6.3 Quantitative definition of system boundaries – the cut-off criteria (Refers to ISO 14044:2006 chapter 4.2.3.3.3) Cutting off data vs. using data estimates In general, all processes and flows that are attributable to the analysed system (or affected via consequences, in case of consequential modelling) are to be included in the system boundaries. However, not all these processes and elementary flows are quantitatively relevant: for the less relevant ones, data of lower quality ("data estimates") can be used, limiting the effort for collecting or obtaining high quality data for those parts


Among these, the irrelevant ones can be entirely cut-off (and the effort that would otherwise be needed to collect the data can be used to focus on obtaining better data for the relevant processes and elementary flows). Terms and concepts: Cut-off criteria "Cut-off" refers to the omission of not relevant life cycle stages, activity types (e.g. investment goods, storage, ...), specific processes and products (e.g. re-granulating of internally recycled polymer production waste before re-melting) and elementary flows from the system model. Cut-offs are quantified in relation to the percentage of environmental impacts that is approximated to be excluded via the cut-off (e.g. "95 %" relates to cutting off about 5 % of the total environmental impact (or of a selected impact category)). Obviously does it a require


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how an approximation to know what is the 100 % impact, because if one would know the total impact exactly, there would be no need for a cut-off. But the total inventory is always unknown for all life cycle approaches - the 100 % always need more or less approximation and extrapolation from the measured or calculated data. Important is that the part that is cut-off is not too big, as this has firstly the effect of having incomplete data (i.e. lower environmental impacts) that limits the suitability of the results for comparisons. Secondly does a bigger gap of off-cut processes, flows etc. also lead to higher overall uncertainty: the quantitative estimate of the % impact that is cut-off is more and more imprecise, the more is cut off. More details on cut-offs are provided in this chapter


More details on cut-offs are provided in this chapter. Important is also that the cut-off is determined systematically, to avoid inappropriately cutting off relevant parts. Relationship between significance of results and cut-off criteria The quantitative definition of the system boundaries concerns the permissible omission of whole life cycle stages, activity types, specific processes and products, and elementary flows. Such omissions (“cut-offs”) can however only be justified if they are insignificant to the outcome of the LCI/LCA study. Otherwise they have to be considered in the interpretation phase. For LCI data sets, the cut-off is one of the data quality criteria (see chapter 12) that shall be documented. The meaning of the above “insignificant” is to be derived through the formulation of quantitative cut-off criteria


The meaning of the above “insignificant” is to be derived through the formulation of quantitative cut-off criteria. These define the minimum required completeness of the data in view of its maximum permissible uncertainty, lack of accuracy and inconsistency in view of the intended application of the results. Note that the various data quality components always interrelate (e.g. can the completeness of 90 % be achieved with "high quality" data, or with a lower quality "data estimate"; see annex Table 6 for the data quality levels). The use of data estimate data again would make the approximation of the 100 % as reference less precise, and so on. It is also to be noted, that the data quality components interact in a multiplicative way and that typically the weakest of the data quality components lowers the overall data quality to its level or below. When defining e.g


When defining e.g. cut-off criteria, this is hence to be done both in view of the required minimum quality along the goal and scope of the study and in view of the achieved quality for the other data quality components. An example: In a comparative assertion study of two product systems it may be found during the iterative analysis that the environmental impact of the two alternatives differs very clearly and always in favour of the same product system (say: about between 60 and 90 % of difference for the individual midpoint level impact categories). The available data might be of high to very high accuracy and precision as most key processes are in the foreground system and measured annual data is available. The minimum required final completeness of the life cycle system data of the two product alternatives could hence be identified to be e.g. 80 %77, as this might still allow demonstrating that the two alternatives differ significantly. I.e


80 %77, as this might still allow demonstrating that the two alternatives differ significantly. I.e. the quantitative cut-off would be set to “80 % minimum completeness”, i.e. a rather low degree of completeness. For LCI data sets that are application-unspecific (e.g. average data for background use in decision-context studies under Situation A), in principle the cut-off can be set freely, while the 77 The above "X %" can be derived only iterative after initial system modelling, of course. The use of stochastic methods would help to determine the exact minimum required degree of completeness cut-off %. This would need to also consider data accuracy and precision as all influence the overall significance of differences.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how exact cut-off set is to be documented to allow data users to evaluate the suitability of the data for their specific LCI/LCA study. Defining quantitative cut-off criteria / completeness of data Valid cut-off criteria are to be defined based on the quantitative degree of completeness of the overall environmental impacts of the product system (e.g. “covering 85 % of the overall environmental impacts”). Two approaches are feasible:  relating the cut-off to each and any of the to-be-included impact categories (i.e. "85 % of Climate change potential AND 85 % of Acidification potential AND 85 % of Eutrophication potential AND etc.") This requires that the LCIA methods have been identified at that point; see chapter 6.7.  relating the cut-off to the normalised and weighted overall environmental impact (i.e


 relating the cut-off to the normalised and weighted overall environmental impact (i.e. 85 % of the normalised and weighted overall environmental impact). This requires the identification and use of the normalisation basis and the weighting set, see chapter 6.7.6. The advantage of using the first named approach is that one can work without normalisation and weighting data. The advantage of the second approach is that the effort can be focussed on the most relevant impact categories, while in the first name case also data needs to be collected that is of very little relevance, i.e. for impact categories that have little relevance for the analysed process or system. Note that in case of Carbon footprints and other studies that apply a limited set of impact indicators, the cut-off will relate to the considered indicators only (e.g. “covering 90 % of the Climate change impacts”)


“covering 90 % of the Climate change impacts”). An example for the definition of the criteria in a specific study or data set is: “The cut-off criteria is the overall environmental impact of the analysed product system given by its normalised and weighted LCIA results, applying the XY LCIA methods, the XY normalisation basis, and the XY weighting set78. The study (or data set) covers the processes and flows that contribute at least 95 % of this impact.” The percentage (here e.g. “95 %”) is to be derived for the given case from the goal and scope of the LCA study (or is directly set in the goal definition for background LCI data sets), as discussed before


“95 %”) is to be derived for the given case from the goal and scope of the LCA study (or is directly set in the goal definition for background LCI data sets), as discussed before. Preceding remark on applying cut-off criteria in practice The application of cut-off criteria has to consider two main aspects: the translation of the cut-off criteria into operational criteria during data collection of the individual unit-processes and - before that - the procedural issue of how to overcome an apparent paradox: The apparent paradox is that one must know the final result of the LCA (so one can show that the omission of a certain process is insignificant for the overall results) to be able to know which processes, elementary flows etc. can be left out


can be left out. This paradox is solved through the iterative approach used when performing an LCA, as described in chapter 4 and with more details on the inventory part in Figure 5: the initial settings are to be revisited once or several times and refined in view of the outcome of the subsequent LCI data collection, modelling (including of alternative scenarios), LCIA results calculation, and interpretation (especially contribution, sensitivity, completeness checks and uncertainty analysis). These 78 Until ILCD recommended LCIA methods, normalisation data and weighting sets are available, other internationally accepted and widely used sources are to be applied for LCA studies and hence also for defining and applying the cut-off criteria. Especially when developing and publishing LCI data sets for background use it is recommended to apply more than one combination of LCIA method, normalisation, and weighting and document the respective coverages.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how iterative steps are to be repeated until the results meet the completeness, accuracy and precision requirements as needed for the intended applications of the LCI/LCA study. Details on the application of cut-off criteria in data collection and modelling are given in chapter 7.4.2.11 and 9.3.2. Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness) Differentiated applicability to Situation A, B, and C. Differentiated for attributional and consequential modelling. Note that these provisions will be applied only in the LCI phase


Differentiated for attributional and consequential modelling. Note that these provisions will be applied only in the LCI phase. I) SHALL - Scope of LCA: The following shall be covered by the LCI or LCA study (6.6.1): I.a) potential impacts on the three areas of protection Human health, Natural environment, and Natural resources, I.b) that are caused by interventions between Technosphere and Ecosphere, and this I.c) during normal and abnormal operation, but excluding accidents, spills, and similar79. I.d) Other kinds of impacts outside the scope of LCA that are found relevant for the analysed or compared system(s) may be identified and their relevance be justified


I.d) Other kinds of impacts outside the scope of LCA that are found relevant for the analysed or compared system(s) may be identified and their relevance be justified. [ISO+] II) SHALL - Processes within the system boundary: The final system boundary/ies of the analysed system(s) shall as far as possible include all relevant life cycle stages and processes that II.a) are operated within the technosphere, and II.b) that need to be included along the provisions of identifying to-be-included processes under attributional or consequential modelling (see chapters 7.2.3 and 7.2.4, respectively), but with the specific provisions and simplifications for the applicable Situation A, B, or C (details see chapter 6.5.4). II.c) Any relevant deviation / omission from the above shall be clearly documented and in case of LCA studies later be considered in the interpretation


II.c) Any relevant deviation / omission from the above shall be clearly documented and in case of LCA studies later be considered in the interpretation. (6.6.1) III) SHALL - Flows across the system boundary: Next to the reference flow(s) that provide the functional unit(s) and permissible waste flows (see 7.4.4.2), no relevant other flows shall cross the boundary between the analysed system(s) and the rest of the technosphere, as far as possible. Only elementary flows (including permissible measurement indicators and flow groups, see 7.4.3.2) should cross the boundary between the analysed system(s) and the ecosphere. Any relevant deviation / omission from the above shall be reported and in case of LCA studies later be considered in the interpretation (6.6.1). [ISO!] Note: see also chapter 7.4.4 with special provisions for specific types of processes. 79 I.e


[ISO!] Note: see also chapter 7.4.4 with special provisions for specific types of processes. 79 I.e. excluding accidents, indoor and workplace exposure, as well as impacts related to direct application or ingestion of products to humans (see text and footnote in chapter 6.6.1).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness) IV) SHALL - System boundary diagram: The extent of the system model shall be identified and a schematic system boundary diagram be prepared80, 81. Next to the included life cycle stages, the following shall be provided for the different types of deliverables (6.6.2): [ISO!] IV.a) For single operation unit processes: the process step to be represented. IV.b) For black box unit processes: the to-be-represented e.g. process-chain, plant, site, etc. and the first and last process step included. IV.c) For LCI results, LCIA results and non-comparative LCA studies: the included life cycle stages. Finally, the first and/or last process step included shall be given, unless the life cycle starts or ends with the cradle or grave, respectively


Finally, the first and/or last process step included shall be given, unless the life cycle starts or ends with the cradle or grave, respectively. IV.d) For comparative LCA studies: for each of the compared options the included life cycle stages. In addition, for each of the options the first and/or last process steps included shall be given, unless the respective life cycle starts or ends with the cradle or grave, respectively. IV.e) Flow chart: Especially for the foreground system, it is recommended to already prepare technical flow charts on the main process steps. V) SHALL - List of exclusions: Prepare an initial list of any types of activities, specific processes, product and waste flows, elementary flows or other parts that would be foreseen to be excluded from the analysed system, if any (6.6.2). [ISO+] Note that this initial list is to be (iteratively) updated to reflect the situation at the end of the study


[ISO+] Note that this initial list is to be (iteratively) updated to reflect the situation at the end of the study. Note that any final exclusion will need to be justified referring to the cut-off criteria and may limit the applicability of the resulting data set or the conclusions that can be drawn from a comparative study. VI) SHALL - Part-system and system-system relationships: For studies on parts that have a part-system relationship and on systems that have a system-system relationship, obtain data on the effects on the related systems and their data, as far as this is necessary in line with the goal and scope of the study (6.6.2). The related boxes in chapter 7.2.2 provide more information on this issue. [ISO!] VII) SHALL - System-external off-setting: Off-set emissions (e.g


The related boxes in chapter 7.2.2 provide more information on this issue. [ISO!] VII) SHALL - System-external off-setting: Off-set emissions (e.g. due to carbon off-setting by the Clean Development Mechanism, system-external carbon credits), and other, similar measures outside the analysed system shall not be included in the system boundaries, as far as they are relevant for the results. The related (reduced) emissions shall not be integrated into the inventory or used in LCA results interpretation (6.6.2). [ISO+] 80 The recommended formal system boundary template is found in Figure 35. 81 Other systems that become part of the analysed system in case system expansion is applied should not be shown in this diagram, but the quantitatively most relevant cases of multifunctional processes (as identified in the sensitivity analysis) shall be listed


This includes the quantitatively relevant cases of part-system relationships, which only exceptionally require an expanded system boundary diagram (e.g. if the analysed product would be the "part" of a part-system relationship such shall be provided).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness) VIII) SHALL - Quantitative cut-off criteria: Define the cut-off % value to be applied for the analysed system's product, waste and elementary flows that cross the system boundary, but that are not quantitatively82 included in the inventory83, as follows (6.6.3): VIII.a) Overall environmental impact: The cut-off % value shall generally relate to the quantitative degree of coverage of the approximated overall environmental impact of the system84. For comparative studies the cut-off shall additionally also always relate to mass and energy. Two alternative options exist how to address the overall environmental impact: [ISO!] VIII.a.i) a) apply the cut-off individually for each of the to-be-included85 impact categories


Two alternative options exist how to address the overall environmental impact: [ISO!] VIII.a.i) a) apply the cut-off individually for each of the to-be-included85 impact categories. This requires that the LCIA methods have been identified at that point; see chapter 6.7.7. VIII.a.ii) b) apply the cut-off for the normalised and weighted overall environmental impact. This requires that the LCIA methods, normalisation basis and the weighting set have been identified at that point; see chapter 6.7.7. VIII.b) Identify the aimed-at % cut-off: The aimed at quantitative cut-off / completeness percentage shall be identified as follows: VIII.b.i) For unit processes, LCI results and LCIA results: the cut-off value has either already been defined in the goal phase (e.g. "Development of a single operation unit process data set of 95 % completeness") or is to be derived from the respective completeness need of the intended application in the iterative scope steps


"Development of a single operation unit process data set of 95 % completeness") or is to be derived from the respective completeness need of the intended application in the iterative scope steps. VIII.b.ii) For non-comparative LCA studies: the cut-off value has been identified depending on the detail of interest when analysing the system for key contributing processes and elementary flows; this has been defined typically in the goal of the study. VIII.b.iii) For comparative LCA studies: the cut-off value is set depending on how much precision, accuracy and completeness is needed to show significant differences between the compared systems. This is done in the iterations of the LCA work after at least an initial LCI model has been modelled and analysed. Note that, unless it was initially defined, the cut-off can only roughly be approximated in the initial scope phase and has to be adjusted iteratively. Note that later deviations from the initially set cut-off criteria, e.g


Note that later deviations from the initially set cut-off criteria, e.g. due to lack of data (see chapter 7.4.2.11.3 82 The respective flows shall however be foreseen to be identified and stay in the inventory, but without stating an amount and being marked as "missing relevant" or "missing irrelevant", as applicable. Details see Life Cycle Inventory chapter. 83 Note that co-functions are initially part of the inventory and only later removed via allocation or addressed with system expansion/substitution. 84 While the true absolute overall impact (i.e. the "100% completeness") cannot be known in LCA and other such models, it can be approximated in practice in an iterative manner and with sufficient precision to serve as practical guidance and use for cut-off. Guidance of applying cut-off in practice see 9.3.2. 85 For studies with limited impact coverage (e.g. Carbon footprint), only these categories are to be considered, accordingly.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness) on dealing with missing data), are to be identified in the subsequent LCI data collection and modelling and are to be documented at the end of the LCI/LCA study. The finally achieved cut-off (and any possible deviations) shall be reported and have to be fully reflected in the interpretation phase, in case of an LCA study. Both may lead to a revision of the supported intended applications of the LCI/LCA study. These issues are to be checked in the respective phase of the LCA work. 6.7 Preparing the basis for the impact assessment (Refers to ISO 14044:2006 chapters 4.2.3.4, 4.4.2.2, and 4.4.5) 6.7.1 Introduction and overview Life Cycle Impact Assessment serves to aggregate the inventory data in support of interpretation


Optionally, normalisation and weighting may be applied to further support this. See also Figure 15. Figure 15 Life cycle impact assessment. Schematic steps from inventory to category endpoints. Note that normalisation and weighting are not shown and can start from either midpoints or endpoints. At the same time impact assessment (and optionally normalisation and weighing) are also required for applying cut-off rules to assess data completeness, i.e. for all LCA/LCI studies. They are hence required if the deliverable of the study is an LCI data set. The environmental impact categories that are to be covered in the life cycle impact assessment (chapter 886) as well as the to-be-applied LCIA methods and the normalisation and weighting sets (if included) shall be determined prior to the initial inventory analysis, as far as feasible. This is to ensure that their selection is not done interest-driven in view of the initial results


This is to ensure that their selection is not done interest-driven in view of the initial results. This also ensures that relevant and matching inventory data is collected for the 86 As the selection of LCIA methods is understood to be a scoping issue from the perspective of performing LCA studies, all related steps are joined in this scope chapter. The later LCIA chapter is exclusively applying them, calculating LCIA results. The development of LCIA methods and factors is outside ISO 14044 and outside this document and supported by a separate document "Framework and Requirements for Environmental Impact Assessment Methods, Models and Indicators for Life Cycle Assessment (LCA)". Environmental mechanism (impact pathway) Endpoints Midpoints NOx, Cd, CO2, CH4, dioxins, hard coal, silver from ore, land use, ..


Environmental mechanism (impact pathway) Endpoints Midpoints NOx, Cd, CO2, CH4, dioxins, hard coal, silver from ore, land use, ... and other emissions and resource flows Inventory Climate change Ozone layer Acidification Summer smog Carcinogens Land-use Ecotoxicity (freshwater, marine, terrestrial) Eutrophication Resource depletion Respiratory inorganics Radiation Damage to human health Damage to ecosystem diversity Resource scarcity Human Health Natural environment Natural resources Area of Protection Human toxicity


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how processes in the system, respectively that appropriate third-party background LCI data sets can be identified. The selection of impact categories and normalisation and weighting sets shall be consistent with the goal of the LCI/LCA study. An analysis based on the LCI alone without an impact assessment may in some cases be justified depending on the goal of a LCI/LCA study, but it should be noted that this procedure can limit a valid interpretability of results and comparisons. Comparative assertions based on LCI results alone are not permissible under ISO 14044:2006. The selection of impact categories must be comprehensive in the sense that they cover all relevant environmental issues related to the analysed system (e.g. product). This is unless in the goal definition a limitation was set as e.g


product). This is unless in the goal definition a limitation was set as e.g. in case of Carbon footprint studies, where exclusively Climate change relevant interventions are considered. The initial exclusion of relevant impacts shall be clearly documented and considered in the interpretation of the results, potentially limiting conclusions and recommendations of the study. The use of a globally common LCIA methodology and models with global default characterisation factors and – as far as being available and necessary – with non-generic (e.g. differentiated in location or time) characterisation factors would substantially improve comparability of LCA on a global basis. However, as such is not yet available and widely agreed, this guidance has to be operational without such. The following subchapters give the provisions on how to prepare the basis for a correct impact assessment that will then be carried out after life cycle inventory data collection and modelling


The following subchapters give the provisions on how to prepare the basis for a correct impact assessment that will then be carried out after life cycle inventory data collection and modelling. 6.7.2 Identifying LCIA methods to be applied (Refers to ISO 14044:2006 chapters 4.2.3.4, 4.4.2.2, and 4.4.5) Midpoint and endpoint level impact assessment - requirements LCIA methods exist for midpoint and for endpoint level, and for both in integrated LCIA methodologies (see Figure 15). Both levels have advantages and disadvantages, which are discussed in more detail in the separate guidance document “Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators”. Also the concepts of midpoint and endpoint are detailed in that document


Also the concepts of midpoint and endpoint are detailed in that document. In general, on midpoint level a higher number of impact categories is differentiated (typically around 10) and the results are more accurate and precise compared to the three Areas of Protection at endpoint level that are commonly used for endpoint assessments. The following impact categories at midpoint level and Areas of Protection shall be checked per default for relevance for the study and related LCIA methods are to be identified that will be used in the life cycle impact assessment phase of the LCA:  Impact category: - Climate change, (Stratospheric) Ozone depletion, Human toxicity, Respiratory inorganics, Ionizing radiation, (Ground-level) Photochemical ozone formation, Acidification (land and water), Eutrophication (land and water), Ecotoxicity, Land use, Resource depletion (minerals, fossil and renewable energy resources, water)


 Areas of Protection: - Human health, Natural environment, Natural resources By default all the above impact categories should be covered by the combination of selected LCIA methods. If available and eligible (see below), it is recommended to use them together with coherent impact factors on the endpoint level.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how The selection or development of any LCIA methods shall meet the following requirements, in line with ISO 14044:2006 (details are addressed as part of the separate guidance on “Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators”):  The impact categories, category indicators and characterisation models should enjoy international acceptance. LCIA methods that are endorsed by a governmental body of the relevant region where the decision is to be supported (Situation A, B) or where the reference of the accounted system is located (Situation C), if available. The ILCD System is preparing recommendations regarding impact categories, models, methods as well as related characterisation factors for the reference elementary flows. These may be the basis for such endorsements


These may be the basis for such endorsements.  The category indicators shall include those that are relevant for the specific LCI/LCA study performed, as far as possible


Any gaps shall be documented, and be explicitly discussed in the results interpretation;  The characterisation model for each category indicator shall be scientifically and technically valid, and based upon a distinct identifiable environmental mechanism or reproducible empirical observation;  The entirety of characterisation factors should have no relevant gaps in coverage of the impact category they relate to, as far as possible; relevant gaps shall be approximated, reported and explicitly be considered in the results interpretation,  The category indicators - if endpoint level LCIA methods are included - are to represent the aggregated impacts of the related inputs and outputs of the system on the category endpoint(s);  Double counting should be avoided across included characterisation factors, as far as possible, and unless otherwise required by the goal of the study (e.g


as covering impacts of the same elementary flows to more than one impact categories with alternative impact pathways of the elementary flow);  Value-choices and assumptions made during the selection of impact categories and LCIA methods should be minimized and shall be documented as part of the LCIA method data set documentation and preferably of a more extensive report; An ILCD-compliant LCIA review may be required for eligible LCIA methods. This is addressed in chapter 11 and the separate ILCD review guidance documents. LCIA methods for further impact categories can be integrated into the analysis (see chapter 6.7.4). This may be required for missing impact categories of specific relevance for the LCI/LCA study and to impact factors for study-specific, impact-relevant elementary flows that are not covered in the applied LCIA method. Also non-generic, i.e. spatially or otherwise differentiated LCIA methods may be required; see chapter 6.7.5


Also non-generic, i.e. spatially or otherwise differentiated LCIA methods may be required; see chapter 6.7.5. Depending on the specific system, initial knowledge based on experience gained from detailed and complete studies for sufficiently similar systems or later analysis may show that one or more of the default impact categories are of little overall relevance. Applying the cutoff rules, these impacts can hence be excluded in the further steps, but such an omission shall be quantitatively justified as being insignificant for the overall environmental impact in view of the goal definition and especially the intended applications as well as the cut-off defined for the LCI/LCA study. Note that any relevant exclusion later needs to be explicitly considered during interpretation and can lead to limitations for conclusions and recommendations.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how 6.7.3 Carbon footprint and other selected indicators (No separate corresponding ISO 14044:2006 chapter but relates to chapters 4.2.3.4 and 4.4.2.2) Depending on the intended application, it may already initially be foreseen during the goal definition to operate with a limited selection of environmental impact categories (e.g. “Climate change” in Carbon footprint studies or “Energy resource depletion” in Primary energy consumption oriented life cycle studies). If this is the case, this shall be highlighted and justified in the goal and scope definition. The specific LCIA methods (e.g. using the most recent Intergovernmental Panel on Climate Change (IPCC) factors that are typically used for Carbon footprint studies) shall be identified here


The specific LCIA methods (e.g. using the most recent Intergovernmental Panel on Climate Change (IPCC) factors that are typically used for Carbon footprint studies) shall be identified here. Exclusion of relevant impact is to be highlighted in the documentation of LCI studies/data sets and LCA studies, including the effect of limited comparability of the results with other systems. 6.7.4 Inclusion of non-standard impacts and of non-standard elementary flows (No separate corresponding ISO 14044:2006 chapter but relates to chapters 4.2.3.4 and 4.4.2.2) Additional impact categories Depending on the goal of the LCI/LCA study and the nature of the system, additional relevant environmental issues may need to be addressed. In line with ISO 14044:2006, this inclusion shall be done for missing impact categories of special relevance for the LCI/LCA study. If this is the case, such additional LCIA methods shall be included in the set or may even - in rare cases - have to be developed


If this is the case, such additional LCIA methods shall be included in the set or may even - in rare cases - have to be developed. In other cases, existing LCIA methods may have to be extended with characterisation factors for not yet covered elementary flows that are of special relevance for the analysed system. If this is the case, this need shall be identified as part of the scope definition, in order to identify the required information on elementary flows prior to the inventory analysis. Note that this may be possible only based on insights gained after the first or second iteration of the LCI data collection, modelling, impact assessment and interpretation. Note that any additional impact category, LCIA method and impact factor has to fulfil the same conditions as the ones listed here in context of the default impact categories in chapter 6.7.2


Note that any additional impact category, LCIA method and impact factor has to fulfil the same conditions as the ones listed here in context of the default impact categories in chapter 6.7.2. Additional impact factors It may similarly be found that for the selected LCIA method a characterisation factor is missing for an elementary flow in the inventory, which is known to contribute significantly to the respective impact category or category endpoint. This will typically be identified only based on insights gained after the first or second iteration of the LCI data collection, modelling, impact assessment and interpretation. The necessity to derive / develop such a specific factor for that flow should be evaluated applying the following steps:  The potential importance of the missing characterisation factor should be evaluated by assuming a conservative value or realistic worst case value e.g


based on chemical, physical, and/or other similarity to other elementary flows which contribute to the same impact category in question. An example might be a missing "Acidification potential"


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how factor for emissions to air of Acetic acid as a weak organic acid. Based on the similarity in terms of fate and exposure with Formic acid (as derived from its chemical, photochemical and physico-chemical characteristics such as e.g. water-solubility) a stoichiometrically adjusted factor can be assigned. Similarly, can the Eutrophication potential of an emission to fresh water of urea as a quickly biodegrading nitrogencontaining organic compound be approximated by that of nitrate to water, after stoichiometric conversion of the N-content in the urea.  This assumed characterisation factor should be applied to the elementary flow and be investigated whether the total result for the impact category is changed to a relevant degree (i.e


 This assumed characterisation factor should be applied to the elementary flow and be investigated whether the total result for the impact category is changed to a relevant degree (i.e. depending on the required accuracy, especially the completeness requirements / cut-off rules, as derived from the goal of the study).  If the contribution from the elementary flow cannot on this basis be classified as insignificant, it should be attempted to get a more accurate and precise value for the missing characterisation factor. Note that this factor will have to fulfil the same conditions as other factors of the respective LCIA methods.  If this is not possible, the fact of the missing characterisation factor must be reported and the potential influence of the missing factor must be considered in the interpretation of the results


 If this is not possible, the fact of the missing characterisation factor must be reported and the potential influence of the missing factor must be considered in the interpretation of the results.  If in contrast the conservative / worst case assumption does not lead to a significant contribution from the elementary flow, the missing characterisation factor can be disregarded. It is recommended to report the fact of a "missing factor" nevertheless, at least for those flows that lack relevance but are not fully irrelevant. Note that this procedure requires expert knowledge of an LCIA method developer, especially fate and exposure modelling, and a good chemical and environmental sciences understanding. Also refer to the document “Requirements for Environmental Impact Assessment Methods, Models and Indicators for LCA”


Also refer to the document “Requirements for Environmental Impact Assessment Methods, Models and Indicators for LCA”. 6.7.5 Spatial and other differentiation / modification of impact factors (No separate corresponding ISO 14044:2006 chapter but relates to chapters 4.2.3.4 and 4.4.2.2) ISO 14044:2006 foresees that “Depending on the environmental mechanism and the goal and scope, spatial and temporal differentiation of the characterization model relating the LCI results to the category indicator should be considered.” Given however the lack of spatially or temporally differentiated LCI data and especially corresponding LCIA methods, for the time being such differentiation is in practice not or rarely feasible. If aimed at, the use of such non-generic (e.g. spatially or otherwise differentiated) LCIA methods shall be scientifically justified in so far, that it results in significantly different LCIA results


spatially or otherwise differentiated) LCIA methods shall be scientifically justified in so far, that it results in significantly different LCIA results. Note that independently of this, an ILCD-compliant LCIA review may be required for any applied LCIA methods. This is addressed in chapter 11 and the separate guidance document on “Review schemes for Life Cycle Assessment (LCA)”. Note that, in case non-generic impact assessment is applied, the characterisation step will have to be done on the not aggregated inventory result. After the characterisation step, the LCIA results may be summed up per impact category and can be provided together with the corresponding aggregated LCI results. If such is done, the LCIA results obtained applying non-generic LCIA methods shall be provided in the report in addition to the differentiated ones.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Note that this step is often only possible after the first or second iteration of LCI data collection and modelling. Note that for comparative LCA studies also the appropriateness of the generic LCIA methods shall be discussed in the interpretation phase of the study. If a further, especially spatial or temporal differentiation can be argued to lead to substantially different results, this finding may limit the conclusions and recommendations that can be drawn from the study. Note that LCIA results calculated from non-generic LCIA methods are later to be presented and discussed additionally separately from the default, generic ones


Note that LCIA results calculated from non-generic LCIA methods are later to be presented and discussed additionally separately from the default, generic ones. 6.7.6 Selection of normalisation basis and weighting set87 (No separate corresponding ISO 14044:2006 chapter but relates to aspect “environmental significance” of chapter 4.2.3.4 and to chapter 4.4.3) Introduction Normalisation and weighting are optional steps under ISO 14044:2006 to support the interpretation of the impact profile and are steps towards a fully aggregated result. Note that normalisation and weighting may also be used to define the quantitative cut-off rules (see chapter 6.6.3) and to check the achieved degree of completeness of the data set inventory. This means they may be required independently of the type of deliverable of the LCI/LCA study


This means they may be required independently of the type of deliverable of the LCI/LCA study. Note that not all endpoint level based weighting methods require a normalisation step: those that express the potential damages to the included Areas of protection in a common unit (e.g. monetary methods) operate without an explicit normalisation. In that case the normalisation is implicitly included in the endpoint modelling step. For such methods the use of an additional normalisation step would hence be wrong. For those weighting methods, in contrast, that require a preceding normalisation, a weighting without normalisation would provide wrong results. Frequent errors: Incompatible LCIA methods, normalisation basis, and weighting set It is important to be aware that the chosen LCIA methods, the normalisation basis and the weighting set have to be carefully chosen including that they fit together. I.e. they need to relate to exactly the same midpoint level or endpoint level categories


I.e. they need to relate to exactly the same midpoint level or endpoint level categories. Sometimes only partly or not at all compatible data are combined. This leads to distorted or meaningless results. Also a correct relation of the geographical reference is important to ensure the appropriate decision support. Note: As the development of normalisation and weighting factors is not part of the ILCD System work, these topics is not discussed in detail, but basic guidance along the ISO provisions on their selection is given here below and on their use (see chapters 8.3 and 8.4). Normalisation basis - requirements In normalisation, the indicator results for the different midpoint level impact categories or endpoint level damages are expressed relative to a common reference, by dividing the indicator results by the respective reference value


As reference values typically the impact 87 "Grouping" is not addressed in this guidance document as not seen as adding practical value in context of decision support. If it is planned to include a grouping step in an LCA study, please refer to the ISO 14044 provisions.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how or damage results of the total annual territorial elementary flows in a country, region, or continent, or globally (or per average citizen, i.e. per capita) are used88. These reference impact or damage results are termed “normalisation basis”. The normalisation basis is calculated from the inventory for each of the impact categories or damages in the same way as the impact indicators or damages of the analysed system (e.g. product) are calculated from its life cycle inventory: For midpoint level results the normalisation basis is the overall potential impact, calculated from the annual inventory of elementary flows. For endpoint level results the normalisation basis is the overall damage to the areas of protection


For endpoint level results the normalisation basis is the overall damage to the areas of protection. To ease communication (and quality checks) across studies, it is recommended to use as normalisation basis the elementary flow inventory per capita89 in the selected country/region/globally per year. The decision whether to use global data or data for a specific country, region or continent shall be made during the initial scope definition and shall be justified along the following considerations:  Where are the supported decisions be made (Situations A, B), or where is the reference of the accounting (Situation C)?  Relevance for the intended application(s) and target audience of the LCI/LCA study  Sufficiently complete availability of inventory data for the chosen country, region or globally, and with a sufficiently similar completeness of all impact categories / areas of protection considered in the LCI/LCA study


 The elementary flows of the normalisation basis have to be appropriate for use with the LCIA method used for the LCI/LCA study, i.e. are classified and characterised as are those of the analysed system.  Compatibility with the midpoint impact categories or category endpoints, as applied, and with the set of weighting factors to be subsequently applied, if any (see below). The year of the normalisation basis should be the latest year for which reliable data are available. The chosen normalisation basis should not be changed later on in the study, unless it has to be extended if in the course of the study a non-default impact category has been additionally included. Weighting factors - requirements In weighting, the (typically normalised) indicator results for the different impact categories or damages are each multiplied by a specific weighting factor, that is intended to reflect the relative relevance of the different impact categories / category endpoints among each other


For example the impact category "Acidification potential" may get a weight of e.g. 2 and the impact category of "Photochemical ozone creation potential" a weight of e.g. 3, and so on for all included impact categories. Weighting sets can be developed by different mechanisms such as setting them by public policy makers or industry panels, broader stakeholder panels, expert panels, and so on. 88 Other time-references then one year can be used but are uncommon. 89 This is because values for typical products (e.g. 1 kg fresh tomatoes, 1 private house type X, etc.) the normalised LCIA results in this case are in the range of roughly between 10 down to 0.00001 and have a clear meaning. If a whole country is the normalisation basis the values are in the range of 10-7 down to 10-14 what makes them un-illustrative and also difficult to do quick plausibility checks


If a whole country is the normalisation basis the values are in the range of 10-7 down to 10-14 what makes them un-illustrative and also difficult to do quick plausibility checks. Also, the numbers differ considerably depending on the population size of the country (and not only due to the different overall impact of the average citizen of different countries).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how They can hence reflect a range of scientific expertise but also political and other value-based considerations. It is to be highlighted that weighting factors are intrinsically always normative/subjective and reflect value assumptions. The identification of a suitable weighting set shall be done, justified, and documented during the initial scope phase of the study and in line with its goal, especially the intended applications and target audience. The following considerations are to guide the selection/identification of weighting factors:  Relate to the normative/cultural/religious or other societal setting globally or of the country or region where the supported decisions are made (Situations A, B), or the reference of the accounting (Situation C)


 Relevance for the intended application(s) and target audience of the LCI/LCA study  Refer correctly to the specific set of midpoint level impact categories or endpoint level Areas of protection provided by the LCIA method used for the study  Be regarding chosen country, region or global scope compatible with the set of normalisation factors that were applied, if any. The chosen weighting set should not be changed later during the study, unless it will require extension if in the course of the study a non-default impact category has been additionally included. 6.7.7 Documentation of decision on LCIA methods, impact level, normalisation basis, and weighting factors (No separate corresponding ISO 14044:2006 chapter but relates to chapters 4.2.3.4 and 4.4.3) Especially for comparative assertions disclosed to the public, but also for other deliverables that are meant to support product comparisons by third parties (e.g


EPDs), the selection of the finally to-be-applied LCIA methods and the evaluation level (midpoint or endpoint) shall be made during the initial scope definition. Equally shall the decision about the possible (optional) inclusion of a normalisation and weighting step in support of the results interpretation be made during the initial scope definition. If these decisions would be made or revised after the LCI work has been performed and results have been calculated, this could be interpreted as trying to influence the outcome of the study by selecting the most favourable impact models, impact level, and normalisation/weighting approach and data. These decisions shall be documented or published in an appropriate form and way that allows the critical reviewer to later verify the date when these have been made. Changes of these decisions shall only be possible: - if relevant impact categories and factors for individual elementary flows are added in line with the goal of the study


Changes of these decisions shall only be possible: - if relevant impact categories and factors for individual elementary flows are added in line with the goal of the study. This shall moreover result in an extension of the normalisation basis and weighting set (if included) for the added impact categories and elementary flows. - if using non-generic (e.g. spatially or otherwise further differentiated) LCIA methods upon justification as indicated more above, or - excluding impact categories due to lack of relevance for the overall environmental impact (only applicable if referring the cut-off to the normalised and weighted overall LCIA results). This shall be demonstrated by applying the cut-off rules. It results in


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how the removal of the normalisation value(s) and weighting factor(s) for the affected impact category/ies. Provisions: 6.7 Preparing the basis for the impact assessment Applicable to Situation A, B, and C. Few differences between A/B and C. Note that an impact assessment is required for all types of LCI/LCA studies at least for systematically assessing and improving the overall data quality, including applying the cut-off rules as described in chapter 6.6.3. Impact categories and LCIA methods: I) SHALL - Goal-conform selection of impact categories and LCIA methods: Select the impact categories to be included and the corresponding LCIA methods in accordance with the goal of the study


[ISO!] II) SHOULD - Requirements for impact categories: II.a) All impact categories that are environmentally relevant90 for the LCI/LCA study shall be included, as far as possible and unless the goal definition would explicitly foresee exclusions (e.g. for Carbon footprint studies). Further ones can be included optionally. Note that any relevant exclusion will need to be explicitly considered during interpretation and can lead to limitations for the further use of the data (in case of an LCI study or data set) and in limitations for the conclusions and recommendations (in case of an LCA study). III) SHALL - Requirements for LCIA methods: All included LCIA methods shall meet the following requirements91 (6.7.2): III.a) They should be internationally accepted and preferably additionally be endorsed by a governmental body of the relevant region where the decision is to be supported (Situation A, B) or where the reference of the accounted system92 is located (Situation C)


III.b) They shall be scientifically and technically valid, as far as possible; the extent of this fact shall be documented. III.c) They shall have no relevant gaps in coverage of the impact category they relate to, as far as possible; otherwise the gap shall be approximated, reported and explicitly be considered in the results interpretation, III.d) They shall be based upon a distinct identifiable environmental mechanism or reproducible empirical observation, 90 As this can be judged only in view of the LCIA results, i.e. after LCI data collection, modelling, etc., it is recommended to initially foresee the inclusion of all of the default impact categories (see next action). If the impact assessment later shows irrelevance of one of more impact categories they can be left out; see also further provisions. For principally restricted assessments (e.g. Carbon footprint) see the respective action below


For principally restricted assessments (e.g. Carbon footprint) see the respective action below. 91 Under the ILCD, recommendations are under preparation on a complete set of such LCIA methods that provide characterisation factors for the ILCD reference elementary flows. These will relate to European and/or global scope, depending on their applicability. 92 "Reference of the accounted system" refers to e.g. the country or region for which a consumption, production, or territorial indicator is modelled, or to the country in which the company is located that models accounting data for its key products.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.7 Preparing the basis for the impact assessment III.e) They shall be related exclusively to elementary flows (i.e. interventions between the technosphere and the ecosphere) during normal and abnormal operating conditions, but excluding accidents, spills, and the like. [ISO!] III.f) They shall be free of double-counting across included characterisation factors, as far as possible and unless otherwise required by the goal of the study, and III.g) They shall be free of value choices and assumptions, as far as possible; these shall be appropriately documented and if relevant they shall explicitly be considered in the results interpretation


The development or identification of LCIA methods that are prepared to meet these requirements is supported with the separate guidance document “Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators”. Note that for use in comparative assertion studies any used LCIA method and factor may need to undergo a review under ISO in order to be eligible. IV) SHOULD - Default impact categories and category endpoints: The selected LCIA methods in their entirety should by default cover all of the following impact categories and provide characterisation factors on midpoint level


It is recommended that they also provide modelled category endpoint factors that are coherent with the midpoint level and that cover all relevant damages to the three following areas of protection (6.7.2): IV.a) Impact categories ("midpoint level"): Climate change, (Stratospheric) Ozone depletion, Human toxicity, Respiratory inorganics, Ionising radiation, (Groundlevel) Photochemical ozone formation, Acidification (land and water), Eutrophication (land and water), Ecotoxicity (freshwater, marine, terrestrial), Land use, Resource depletion (of minerals, fossil and renewable energy resources, water, ...). [ISO!] IV.b) Category endpoints ("endpoint level"): Damage to human health, Damage to ecosystem, Depletion of natural resources. These relate to the three areas of protection "Human health", "Natural environment", and "Natural resources", respectively


These relate to the three areas of protection "Human health", "Natural environment", and "Natural resources", respectively. [ISO+] V) SHOULD - Location and time generic LCIA: The LCIA methods should by default be location-generic and time-generic (but see later provision on derived LCIA methods). [ISO!] VI) MAY - LCIA methodologies: It is recommended to select available LCIA methodologies that provide a complete set of single LCIA methods, rather than selecting and combining individual LCIA methods. [ISO!] VII) SHOULD - Excluding impact categories?: Exclusions of any of the above impact categories should be justified as being not relevant for the analysed system(s). This can be done based on experience gained from detailed, complete studies for sufficiently similar systems and/or system group specific / Product Category Rule (PCR) type guidance documents


This can be done based on experience gained from detailed, complete studies for sufficiently similar systems and/or system group specific / Product Category Rule (PCR) type guidance documents. (6.7.2 and 6.7.3) [ISO+] VIII) SHALL - Adding impact categories?: Check for the specific LCI/LCA study whether next to the default impact categories given above, additional, relevant environmental


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.7 Preparing the basis for the impact assessment impacts93 need to be included in accordance with the goal and scope. If so, identify or develop94 the relevant LCIA methods to be applied. Note that these shall meet the same requirements as the other included LCIA methods (see above) (6.7.4). IX) SHOULD - Impacts outside the scope of LCA: Impacts that are outside the LCA frame95, 93 but for which scientific evidence exists that they are relevant for the analysed or compared system(s) should be clearly and individually be identified, including in the Summary and Executive summary of the report / data set. Their brief description should be foreseen in the further documentation. If it is foreseen to include them quantitatively, this requires potentially different modelling and analysis approaches and guidance


If it is foreseen to include them quantitatively, this requires potentially different modelling and analysis approaches and guidance. This should be done jointly with the LCA study, as far as possible, to ensure coherence, but inventory, impact assessment, etc. shall be kept separately for clear interpretation (6.7.4). [ISO!] Note that this step is often possible only after the first or second iteration of LCI data collection and modelling, impact assessment, and interpretation


[ISO!] Note that this step is often possible only after the first or second iteration of LCI data collection and modelling, impact assessment, and interpretation. X) SHOULD - Missing characterisation factors: If a characterisation factor is missing for an elementary flow of the analysed inventory, and that flow is known to contribute significantly to one or more of the included impact categories, considering the goal and scope of the LCI/LCA study (6.7.4): [ISO+] X.a) Check the potential importance of the missing characterisation factor by assuming a conservative value or reasonably worst case value based on chemical, physical, biological and/or other similarity to other elementary flows which contribute to the same impact category/ies in question


Note that this procedure requires expert knowledge of an LCIA method developer, especially on fate and exposure modelling to be able to judge which similarities to consider and how; a good chemical and environmental sciences understanding is equally required. X.b) Apply the assumed characterisation factor(s) to that elementary flow and investigate whether the total result for the affected impact category/ies is changed to a relevant degree (i.e. depending on the required completeness, accuracy, and precision). X.c) If with this approach the contribution from this elementary flow cannot be classified as being not relevant, it should be attempted to get a more accurate and precise value for the missing characterisation factor and use that one for the further work. Note that this factor will have to fulfil the same conditions as other factors of the respective impact 93 Examples are Noise, Desiccation / Salination, Littering of land and sea, etc


Note that this factor will have to fulfil the same conditions as other factors of the respective impact 93 Examples are Noise, Desiccation / Salination, Littering of land and sea, etc. 94 ISO 14044 requires that all relevant impacts are to be covered. In practice of performing LCA studies, the development of new LCIA methods is a rare case. The separate guidance document "Development of Life Cycle Impact Assessment (LCIA) models, methods and factors" supports LCIA method developers in this step. 95 The inventory related to impacts that are outside the frame of LCA shall not be mixed with the for LCA impacts, i.e. need separate inventorying as separate items outside the general Inputs/Outputs inventory. The LCA frame covers potential impacts on the named three areas of protection that are caused by interventions between Technosphere and Ecosphere during normal and abnormal operation. I.e


The LCA frame covers potential impacts on the named three areas of protection that are caused by interventions between Technosphere and Ecosphere during normal and abnormal operation. I.e. Accidents, indoor and workplace exposure, as well as impacts related to direct application or ingestion of products to humans shall not be mixed but be modelled and inventoried separately (see also 6.8.2).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.7 Preparing the basis for the impact assessment category / method. X.d) If the latter is not possible or the whole provision is not feasible (e.g. for cost or timing reasons), the fact of a missing relevant characterisation factor shall be reported and the potential influence of the missing factor shall be considered when reporting the achieved data quality and (for LCA studies) in the interpretation of the results. X.e) If the conservative or reasonably worst case value does not show a relevant contribution from that elementary flow, the missing characterisation factor can be disregarded. It is recommended to report the fact of a "missing factor" nevertheless and marked as "missing unimportant", at least for those flows that lack relevance but are not fully negligible


It is recommended to report the fact of a "missing factor" nevertheless and marked as "missing unimportant", at least for those flows that lack relevance but are not fully negligible. Note that this step is often only possible after the first or second iteration of LCI data collection and modelling, impact assessment, and interpretation. XI) SHALL - Location and time non-generic LCIA methods: The potential use of LCIA methods that have been derived from the original, location-generic and time-generic ones (i.e. being not generic but e.g. spatially or otherwise further differentiated or modified) shall be justified along the goal and scope of the study. It shall be demonstrated that significantly different LCIA results are obtained than with the generic methods. The non-generic methods have to meet the other applicable requirements for selected LCIA methods (6.7.5)


The non-generic methods have to meet the other applicable requirements for selected LCIA methods (6.7.5). [ISO!] Note that this step is often only possible after the first or second iteration of LCI data collection and modelling, impact assessment, and interpretation. Note that for comparative LCA studies also the appropriateness of generic LCIA methods shall be discussed in the interpretation phase of the study. If a further differentiation can be argued or approximated to lead to significantly different results, this finding may limit the conclusions and recommendations that can be drawn from the study. Note that LCIA results calculated from non-generic LCIA methods are later to be presented separately from the generic ones and discussed jointly. Normalisation and weighting: XII) SHALL - Cut-off criteria: Normalisation and weighting may have been used for defining the cut-off rules in chapter 6.6.3 (6.7.6)


Normalisation and weighting: XII) SHALL - Cut-off criteria: Normalisation and weighting may have been used for defining the cut-off rules in chapter 6.6.3 (6.7.6). [ISO!] XIII) MAY - Results interpretation: Normalisation and weighting are in addition optional steps under ISO 14044:2006 that are recommended to support the results interpretation. (6.7.6) Note that the normalisation and weighting shall be made in accordance with the intended application of the LCI/LCA study. Note that if the study includes a comparative assertion to be disclosed to the public, quantitative weighting of the published indicator results is not permitted. XIV) SHALL - Consistency between cut-off and interpretation: If used in support of results interpretation, the same normalisation and weighting set shall be used as for the cut-off rules (6.7.6)


XIV) SHALL - Consistency between cut-off and interpretation: If used in support of results interpretation, the same normalisation and weighting set shall be used as for the cut-off rules (6.7.6). [ISO!] XV) SHALL - Requirements for selecting normalisation basis and weighting set: If used for defining the cut-off and/or in support of the interpretation of the results of the study,


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.7 Preparing the basis for the impact assessment select a suitable normalisation basis and weighting set96, along the following rules (6.7.6): [ISO!] XV.a) Normalisation basis: XV.a.i) As normalisation basis the annual total environmental inventory globally should be preferred. Alternatively the territory-based or consumptionbased annual total environmental inventory of the country or region should be used where the supported decisions are made (Situations A, B) or in which the accounting reference is located (Situation C). It is recommended to prefer the average citizen as normalisation basis instead of the global, regional or country total (i.e. the global, regional or country total divided by the number of citizen97). XV.a.ii) Ensure the relevance of the selected normalisation basis for the intended applications and target audience


the global, regional or country total divided by the number of citizen97). XV.a.ii) Ensure the relevance of the selected normalisation basis for the intended applications and target audience. XV.a.iii) Ensure a high degree of completeness and precision of the overall environmental impact covered and a similar degree of completeness and precision for all covered impact categories. XV.a.iv) Ensure a proper link with the used LCIA methods, i.e. relate to the same impact categories / areas of protection and use to a sufficient degree the same elementary flows. XV.a.v) Ensure technical compatibility with the to-be-used weighting set, i.e. relate to the same impact categories / areas of protection. XV.a.vi) As year for the normalisation basis the year should be used for which the latest data are available that meet the above requirements


XV.a.vi) As year for the normalisation basis the year should be used for which the latest data are available that meet the above requirements. XV.b) Weighting set: XV.b.i) The weighting set should represent the normative and other values globally or of the country or region where the supported decisions are made (Situations A, B), or the reference of the accounting (Situation C). The weighting set should preferably be endorsed by a governmental body of the country or region where the decision is to be supported (Situation A, B) or where the reference of the accounted system is located (Situation C). XV.b.ii) Ensure the relevance of the selected weighting set to the intended applications and target audience. XV.b.iii) The weighting set shall correctly refer to the used normalisation basis and to the midpoint level or endpoint level indicators of the used LCIA methods, as applied


XV.b.iii) The weighting set shall correctly refer to the used normalisation basis and to the midpoint level or endpoint level indicators of the used LCIA methods, as applied. XV.c) Extension for added impact categories: If in the course of the study a nondefault impact category has been additionally included, corresponding data for 96 The development of governmentally supported corresponding normalisation and weighting data in the different regions and countries or globally would be beneficial. 97 This brings the values of the normalised impacts for goods and services down to a better communicatable and interpretable level (typical value range 10 to 0.00001 instead of 1E-7 to 1E-14).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 6 Scope definition - what to analyse and how Provisions: 6.7 Preparing the basis for the impact assessment the normalisation basis and a weighting factor shall be additionally provided and used98. Documentation of selected LCIA methods, and of decision / selection of normalisation and weighting: XVI) SHALL - Verifiable documentation of decision on LCIA methods, impact level, normalisation and weighting: Decide and document now, during the initial scope definition, bindingly on (6.7.7): [ISO!] XVI.a) the LCIA methods to be applied by default, XVI.b) the selected impact level to be used for reporting and interpretation (i.e. midpoint and/or endpoint level), and if foreseen to be used, XVI.c) the specific normalisation and weighting sets to be used for cut-off and for interpretation


midpoint and/or endpoint level), and if foreseen to be used, XVI.c) the specific normalisation and weighting sets to be used for cut-off and for interpretation. XVI.d) These decisions shall be documented or published in an appropriate form and way that allows the critical reviewer to later verify the date when these decisions have been made. XVI.e) Permissible adjustments: Adjustments of these decisions shall only be possible (6.6.7): XVI.e.i) If impact categories are added in line with the goal of the study and meeting the related provisions for their addition given more above. This shall result exclusively in an addition to the already selected LCIA methods, normalisation basis and weighting set for the added impact categories. XVI.e.ii) If using non-generic LCIA methods upon justification as indicated more above