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). 3. SHALL—Requirements for LCIA methods: All included LCIA methods shall meet the following requirements21: 3:1. 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 system is located (Situation C). 3:2. They shall be scientifically and technically valid, as far as possible; the extent of this fact shall be documented. 3:3. 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, 3:4


They shall be based upon a distinct identifiable environmental mechanism or reproducible empirical observation, 3:5. 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!] 3:6. 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 3:7. 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”

Hauschild et al., LCA: Theory and Practice


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. 4. 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. 21Under 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. M.Z. Hauschild and A. Bjørn


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: 4:1. 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!] 4:2. 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. [ISO+] 5


These relate to the three areas of protection “Human health”, “Natural environment” and “Natural resources”, respectively. [ISO+] 5. 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!] 6. 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!] 7. 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. [ISO+] 8


[ISO+] 8. SHALL—Adding impact categories? Check for the specific LCI/LCA study whether next to the default impact categories given above, additional, relevant environmental impacts22 need to be included in accordance with the goal and scope. If so, identify or develop23 the relevant LCIA methods to be applied. Note that these shall meet the same requirements as the other included LCIA methods (see above). 9. SHOULD—Impacts outside the scope of LCA: Impacts that are outside the LCA frame24 but for which scientific evidence exists that they are relevant for 22Examples are Noise, Desiccation/Salination, Littering of land and sea, etc. 23ISO 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


The separate guidance document “Development of Life Cycle Impact Assessment (LCIA) models, methods and factors” supports LCIA method developers in this step. 24The inventory related to impacts that are outside the frame of LCA shall not be mixed with the inventory 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. 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.


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. 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. [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. 10


[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. 10. 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: [ISO+] 10:1. 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. 10:2. 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). 10:3. 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 category/method. M.Z. Hauschild and A. Bjørn


10:4. 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. 10:5. 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. Note that this step is often only possible after the first or second iteration of LCI data collection and modelling, impact assessment and interpretation. 11


Note that this step is often only possible after the first or second iteration of LCI data collection and modelling, impact assessment and interpretation. 11. 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. [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


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: 12. SHALL—Cut-off criteria: Normalisation and weighting may have been used for defining the cut-off rules. [ISO!] 13. MAY—Results interpretation: Normalisation and weighting are in addition optional steps under ISO 14044:2006 that are recommended to support the results interpretation.


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. 14. 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. [ISO!] 15. 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, select a suitable normalisation basis and weighting set,25 along the following rules: [ISO!] 15:1. Normalisation basis: 15:1:1. As normalisation basis the annual total environmental inventory globally should be preferred


Normalisation basis: 15:1:1. As normalisation basis the annual total environmental inventory globally should be preferred. Alternatively the territory-based or consumption-based 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 citizen26). 15:1:2. Ensure the relevance of the selected normalisation basis for the intended applications and target audience. 15:1:3. 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. 15:1:4. Ensure a proper link with the used LCIA methods, i.e


15:1:4. 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. 15:1:5. Ensure technical compatibility with the to-be-used weighting set, i.e. relate to the same impact categories/areas of protection. 15:1:6. As year for the normalisation basis the year should be used for which the latest data are available that meet the above requirements. 15:2. Weighting set: 15:2:1. The weighting set should represent the normative and other values globally or of the country or region where the supported decisions are made 25The development of governmentally supported corresponding normalisation and weighting data in the different regions and countries or globally would be beneficial. 26This brings the values of the normalised impacts for goods and services down to a better communicable and interpretable level (typical value range 10–0.00001 instead of 1E−7 to 1E−14). M.Z


26This brings the values of the normalised impacts for goods and services down to a better communicable and interpretable level (typical value range 10–0.00001 instead of 1E−7 to 1E−14). M.Z. Hauschild and A. Bjørn


(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). 15:2:2. Ensure the relevance of the selected weighting set to the intended applications and target audience. 15:2:3. 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. 15:3. Extension for added impact categories: If in the course of the study a non- default impact category has been additionally included, corresponding data for the normalisation basis and a weighting factor shall be additionally provided and used.27 Documentation of selected LCIA methods, and of decision/selection of normalisation and weighting: 16


SHALL—Verifiable documentation of decision on LCIA methods, impact level, normalisation and weighting: Decide and document now, during the initial scope definition, bindingly on: [ISO!] 16:1. the LCIA methods to be applied by default, 16:2. the selected impact level to be used for reporting and interpretation (i.e. midpoint and/or endpoint level), and if foreseen to be used, 16:3. the specific normalisation and weighting sets to be used for cut-off and for interpretation. 16:4. 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. 16:5. Permissible adjustments: Adjustments of these decisions shall only be possible: 16:5:1. If impact categories are added in line with the goal of the study and meeting the related provisions for their addition given more above


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. 16:5:2. If using non-generic LCIA methods upon justification as indicated more above. This shall result exclusively in a differentiation of the already selected, generic LCIA methods, unless a best attainable consensus can be found among involved stakeholders on selection of another set of already available non-generic LCIA methods. The normalisation basis and weighting set shall remain unchanged. 27This is not required for use of non-generic LCIA methods and for additionally included single elementary flows/characterisation factors, unless this would relevantly change the results, what by default can be assumed not to be the case.


37.3.7 Special Requirements for System Comparisons When two or more products are compared in an LCA, it is essential that the product systems are modelled consistently in terms of both methodological choices and choices on data to represent the two systems. A qualified consideration of uncertainties is also important when the systems are compared to decide whether one is preferable to the other from an environmental point of view. Particularly strict requirements must be met for comparative assertions disclosed to the public. The provisions from the ILCD guideline for comparisons between systems are the following: Comparisons between systems (Provisions 6.10) These provisions are mandatory (shall) only for comparative LCA studies that analyse more than one system or system variants. It is recommended to also apply them analogously to non-comparative LCA studies that include a system internal contribution/weak point analysis


It is recommended to also apply them analogously to non-comparative LCA studies that include a system internal contribution/weak point analysis. These provisions also apply to LCI studies and data sets that are intended to be used in context of comparative studies (e.g. as background data). For all comparative studies 1. SHALL—Non-assertive, comparative studies: The ISO 14044:2006 provisions for comparative assertions shall also be applied to non-assertive, comparative studies. Both types together are grouped under the term “comparisons” here. [ISO!] 2. SHALL—Consistency: All elements of the scope definition shall be addressed consistently for all systems to be compared, as far as possible. Otherwise, the lack of consistency shall be reported and be considered explicitly when interpreting the results, giving conclusions or recommendations. Especially: 2:1


Otherwise, the lack of consistency shall be reported and be considered explicitly when interpreting the results, giving conclusions or recommendations. Especially: 2:1. LCI model: The compared system models shall be constructed in an analogous way applying the same rules for system boundaries, LCI modelling principles and method approaches. 2:2. Assumptions: Methodological and data assumptions shall be made in an analogous way. 2:3. Data quality: The achieved completeness, accuracy and precision of the data shall be sufficiently similar for the compared systems. 3. SHALL—Uncertainty and accuracy calculations: Calculations on the stochastic uncertainty and accuracy shall support this analysis. This is not required if uncertainty calculations have already been used to derive the reasonably best and worst case scenarios. M.Z. Hauschild and A. Bjørn


4. SHALL—Completeness/cut-off: The cut-off % that has been defined in the study shall also be met for mass and energy, next to for the overall environmental impact. 5. SHALL—Excluding identical parts: If included processes/systems of the compared systems are identical for all alternatives, they may be left out of all models. Included processes/systems that are similar but not identical shall remain in the model, but their partial correlation shall be considered when interpreting differences. [ISO+] Note that the intended applications may not permit to leave out even identical parts. Note that even apparently identical parts may only be left out of the comparison if they are truly identical. For example, the same amount of the same aluminium alloy used in the same component of two alternative models may be left out. This shall not be done if the alloy is used in different components of these models, as the inventories of the alloys are only partly correlated in the second case. 6


This shall not be done if the alloy is used in different components of these models, as the inventories of the alloys are only partly correlated in the second case. 6. SHALL—LCIA to be performed: A Life Cycle Impact Assessment shall be performed for LCI or LCA studies intended to support comparative studies that are intended to be published. 7. SHALL—Impact coverage limitations (e.g. Carbon footprint): Comparison studies based on selected indicators or impact categories (e.g. Carbon footprint-based comparisons) shall highlight that the comparison is not suitable to identify environmental preferable alternatives, as it only covers the considered impact(s) (e.g. Climate change). This applies unless it can be sufficiently demonstrated that the compared alternatives do not differ in other relevant environmental impacts to a degree that would change the conclusions and/or recommendations of the comparison if those other impacts would be included in the analysis


Such demonstration should draw on robust approximations for the analysed system and/or robust information derived from detailed and complete LCA studies available for sufficiently similar systems. System/product-group specific guidance document and Product Category Rules (PCR) may provide such robust information. The above shall be investigated in any case and if other environmental impacts were identified as being relevant in the above sense, they shall be named in the report. [ISO!] For studies on systems with similar functional units: Comparisons shall be made based on the system’s reference flows. 8. SHALL—Functional equivalence: The compared systems shall have the same (or only insignificantly different) functional unit in terms of both the primary function and possible secondary functions, as far as possible. In the case that


some of the aspects of the functional unit(s) differ significantly between the systems, it shall be ensured that: 8:1. either the functions that the compared systems provide are still seen as sufficiently comparable by the main stakeholders affected by the LCA study, 8:2. or the sufficient comparability is to be achieved by the respective method approaches for consequential modelling or attributional modelling,28 as to be applied for the respective Situation. For consequential modelling this approach is system expansion. 9. SHOULD—Selection of compared alternatives: The study should include— next to the foreseen alternatives—potentially environmentally better market relevant and available alternatives, as otherwise the study would be considered misleading. If such alternatives are not included, this shall later be highlighted in a prominent place of the conclusions and recommendations, as well as in the executive and technical summary chapters of the report, pointing to this fact


[ISO+] 10. SHOULD—Selection of production, operation and use scenarios: To ensure a fair comparison, the chosen functional unit should reflect well-justified typical or average production/operation/use scenarios; it shall be agreed with the affected stakeholders in the best attainable consensus. If a typical or otherwise specific scenarios need to be compared in line with to the goal definition, compared, this fact shall later be highlighted in a prominent place of the conclusions and recommendations and executive summary chapter of the report, pointing to this fact. [ISO!] 11. SHOULD—Modelling replacements over time: For cases where a system (e.g. a product) needs to be replaced to meet the required duration of performance of the compared functional unit, the replacement should consider that potentially a newer model or system in general will replace the initially used model. This is unless a different agreement can be achieved among the affected stakeholders


This is unless a different agreement can be achieved among the affected stakeholders. This provision analogously relates to the need of repeating a service. 12. SHALL—Indicative only. Situation A—Assumption scenarios and uncertainty calculation: For comparative micro-level studies (Situation A): each compared scenario shall be complemented with assumption scenarios of reasonably best and reasonably worst cases. This can be optionally extended to further assumption scenarios within the reasonably best and worst cases. Uncertainty calculation shall be performed, unless such has already been used to derive the reasonably best and worst-case scenarios. The interested parties shall be involved in achieving a best attainable consensus on the definition of the reasonably best and reasonably worst assumption scenarios. The 28Comparisons also can occur in accounting type studies (e.g


The 28Comparisons also can occur in accounting type studies (e.g. across product groups in basket-of-product type of studies), while these shall not be used for decision support that would lead to e.g. purchases or policy measures based on superiority or inferiority of the compared alternatives. M.Z. Hauschild and A. Bjørn


assumption scenarios can in principle vary all methods, data and assumptions except for the “shall” provisions. 13. SHALL—Indicative only. Situation B—Assumption scenarios and uncertainty calculation: For comparative meso/macro-level studies of Situation B: the scenarios for each of the analysed alternatives shall apply the modelling guidance of Situation A, except for process that are affected by large-scale consequences of the analysed decision. The assumption scenarios can in principle vary all methods, data and assumptions including the “shall” provisions, but excluding the shall provisions of ISO 14040 and 14044. 14. SHALL—Involvement of interested parties in review [ISO!]. 37.3.8 Needs for Critical Review The only strict requirement is to decide, based on the goal definition and intended application of the LCA, whether a critical review shall be performed, and if so which type of critical review: Identifying critical review needs (Provisions 6.11) 1


SHALL—Review? Decide whether a critical review shall be performed and if so: [ISO!] 1:1. Review type: Decide along the provisions of the separate document “Review schemes for Life Cycle Assessment (LCA)” which type of review is to be performed as minimum. Note that an accompanying review can be beneficial. For Situation B, it can moreover help to organise the best attainable consensus among interested parties, which is required for certain scope decisions. 1:2. Reviewer(s): It is recommended to decide at this point, who is/are the reviewer(s). The minimum requirements on reviewer qualification are discussed in Chap. 13 of this book, which also gives an overview of the review requirements. 37.3.9 Planning Reporting of Results The level of reporting that is required by the intended application of the LCA must be determined already at the onset of the study to ensure that the data needed for the reporting is produced during the study.


Planning reporting (Provisions 6.12) 1. SHALL—Reflecting on the main type of deliverable (i.e. study or data set) and in line with the decision on the target audience(s) and intended application(s), decide on form and level of reporting: 1:1. Form of reporting: Decide which form(s) of reporting shall be used to meet the need of the intended application(s) and target audience(s): [ISO!] 1:1:1. detailed report (including non-technical executive summary), 1:1:2. data set, 1:1:3. data set plus detailed report, or 1:1:4. non-technical executive summary (with references to the full report and review reports, if review has been performed). 1:1:5. The electronic ILCD LCA report template and LCI data set format should be foreseen to be used for reporting. Confidential information can be documented in a separate, complementary report that is not published but only made available to the reviewers under confidentiality


Confidential information can be documented in a separate, complementary report that is not published but only made available to the reviewers under confidentiality. Note that any form of reporting, also more condensed ones, shall ensure that the contained information cannot easily and unintentionally be misunderstood or misinterpreted beyond what is supported by the study. 1:2. Level of reporting: Decide which level of reporting shall be used in accordance with the defined goal. The main levels are: 1:2:1. internal 1:2:2. external (but limited, well defined recipients) 1:2:3. third-party report, publicly accessible 1:2:4. report on comparisons, publicly accessible 37.4 Inventory Analysis The inventory analysis is discussed in Chap. 9 of this book. It is the third phase of the LCA, where the product system is modelled and elementary flow data is collected for all the processes in the system and scaled according to the reference flow of the study


The resulting life cycle inventory is the basis of the subsequent impact assessment. M.Z. Hauschild and A. Bjørn


The inventory analysis comprises the following six steps: 1. Identifying processes for the LCI model 2. Planning and collecting data 3. Constructing and quality checking unit processes 4. Constructing LCI model and calculating LCI results 5. Preparing the basis for uncertainty management and sensitivity analysis 6. Reporting 37.4.1 Identifying Processes for the LCI Model Different approaches are taken for identifying processes for the product system depending on whether an attributional or a consequential modelling approach is taken, as described in Sect. 9.2. The provisions and actions of the ILCD guideline are the following: Identifying processes in attributional modelling (Provisions 7.2.3) Applicable to Situation A and C, as well as the life cycle model(s) of Situation B, except for those process steps that are affected by large-scale consequences. Also applicable to the assumption scenarios under Situation B for which it has been decided to apply attributional modelling


Also applicable to the assumption scenarios under Situation B for which it has been decided to apply attributional modelling. Fully applicable for LCI results, partly terminated systems, LCIA results and LCA studies (and for unit processes only to complete the system model for completeness check and precision approximation). For black box unit processes as deliverable, only those processes that are foreseen to be included are to be identified, as are the product and waste flows that enter or leave the unit process. For single operation unit processes only the product and waste flows that enter or leave the unit process are to be identified and specified; the named technical flow diagram in that case only consists of one process plus product and waste flows. 1. SHALL—Identifying processes within the system boundary: All quantitatively relevant processes shall be identified that are to be attributed to the analysed system(s) and that lay within the system boundary: [ISO+] 1:1


Start from central process: This identification should start from the system’s functional unit or the reference flow (i.e. from the central process of the foreground system or the analysed system itself). 1:2. Foreground system: Stepwise it should be expanded to the entire foreground system. Following a descriptive “supply chain—use—end-of-life” logic it shall as far as possible identify all relevant product and waste flows (or their functional units) that cross the border to or from the background system.


1:3. Background system: The processes in the background system shall be identified in the same “supply chain—use—end-of-life” logic as applied in the foreground system. Note that it is established practice to embed the foreground system into a third-party or in-house developed general background system of LCI results and/or unit processes. That means that in practice the identification described above ends with the identification of the product and waste flows that connect the foreground system with the background system. Systems or processes that would be missing in such a general background system are for a given case collected or obtained from third parties as required for the analysed system. 1:4. Justify and document exclusions: Any exclusion of relevant individual processes or activity types shall be justified using the cut-off criteria


1:4. Justify and document exclusions: Any exclusion of relevant individual processes or activity types shall be justified using the cut-off criteria. This can build on previous experience including as detailed in related system/product-group specific guidance documents or Product Category Rules (PCRs). In principle all processes are to be inventoried that are to be attributed to the system, as far as they relevantly contribute to the overall environmental impact of the analysed system. This includes in principle—depending on the included life cycle stages and the system boundary in general—activities such as, e.g. mining, processing, manufacturing, use, repair and maintenance, transport, waste treatment and other purchased services linked to the analysed system, such as, e.g. cleaning and legal services, marketing, production and decommissioning of capital goods, operation of premises such as retail, storage, administration offices, staff commuting and business travel, etc


Note that individual processes within the background system may need to be identified as well—in context of identifying sensitive issues or if required to meet the specific goal of the study. The requirements regarding technological, geographical and time-related representativeness of the scope definition shall be met. Note that the resulting initial list of processes, product and waste flows typically will need a refinement in view of the results of the completed initial life cycle model, impact assessment and interpretation. M.Z. Hauschild and A. Bjørn


Identifying processes in consequential modelling (Provisions 7.2.4) Applicable for those processes in Situation B that have large-scale consequences, and for use in assumption scenarios in Situation B (if consequential elements are included in those). Fully applicable to all types of deliverables, except for unit processes. Expertise [ISO+] 1. SHOULD—Required expertise: Experts in the following domains should be involved in the study, especially for identifying and modelling large-scale consequences: 1:1. technology development forecasting (e.g. learning curves, experience curves), 1:2. scenario development, 1:3. market cost and market forecasting 1:4. technology cost modelling, and 1:5. general-equilibrium and partial-equilibrium modelling 2. SHOULD—Policy scenario experts required?: The involvement of domain experts for policy scenarios is recommended regarding their function as setting constraints


SHOULD—Policy scenario experts required?: The involvement of domain experts for policy scenarios is recommended regarding their function as setting constraints. In the case policy scenarios are explicitly analysed in the study, such experts should be involved. Identifying consequences and constraints to be considered [ISO+] 3. SHALL—Modelled consequences: Identify among the following ones those consequences that will be modelled; this step may be taken separately case for each process. Their potential exclusion shall justified by demonstrating at least argumentative/semi-quantitative that they are not relevant for the results; otherwise the exclusion shall be considered when reporting achieved accuracy (in case of data sets) and when interpreting the results (in case of LCA studies): 3:1. Primary market consequences: 3:1:1. SHALL—(a) Processes that are operated as direct market consequence of the decision to meet the additional demand of a product (i.e


Primary market consequences: 3:1:1. SHALL—(a) Processes that are operated as direct market consequence of the decision to meet the additional demand of a product (i.e. “consequential modelling of direct consequences; applied for the full system”). This includes among many others also indirect land use effects. 3:1:2. SHALL—(b) Processes that supersede/complement not required co-functions of multifunctional processes that are within the system boundary (i.e. “solving multifunctionality by substitution”, reducing the system boundary to exclude the not required function(s)). 3:2. Secondary market consequences: 3:2:1. SHOULD—Increased demand for a co-product if its market price is reduced. 3:2:2. SHOULD—Incentive-effects on a process to increase its efficiency due to a higher price for its product(s).


3:2:3. SHOULD—Decreased demand for competing products of a co-product due to the decreased price of the co-product. 3:2:4. SHOULD—Consumer behaviour changes 3:2:5. SHOULD—Further consequences should only be included if explicitly addressed in the goal of the study. 4. SHALL—Constraints: Identify the constraints that will be included in the model and that may partly or fully prevent that the marginal process mix as identified along the primary and secondary consequences can directly be used in the system model. The likely specific effect of any included constraint shall be considered when identifying the effective marginal process (es). Their potential exclusion shall be justified by demonstrating at least argumentative/semi-quantitative that they are not relevant for the results; otherwise the exclusion shall be considered when reporting achieved accuracy (in case of data sets) and when interpreting the results (in case of LCA studies)


The following constraints should be considered: 4:1. Existing long-term supply-contracts or co-operations that cannot easily be changed. 4:2. High costs that act as a barrier (e.g. limited mobility of some products due to high transport costs). 4:3. Existing or expected political measures/legal constraints that stimulate perceived positive developments or counteract perceived negative developments. (e.g. a political binding target of X % of energy carrier Y in the fuel mix means that energy carrier X is already pre-set and cannot be assumed to be a long-term marginal product in consequence of the analysed decision.) 4:4. Non-scalability of supply of products or natural resources; including of fully used, dependent co-products of joint production. 4:5. Monopolies, i.e. lack of choice of the supplier or technology. 4:6. It is recommended to also consider other constraints in place or expected to be in place that increase, decrease or block a primary or secondary consequence


4:6. It is recommended to also consider other constraints in place or expected to be in place that increase, decrease or block a primary or secondary consequence. Identifying the mix of superseded processes/systems [ISO+] 5. SHOULD—Stepwise identification of the mix of superseded processes/systems: Identify the processes/systems within the system boundary that are superseded as consequence of the analysed decision on the investigated system(s). For each process the following steps should be applied, starting from the system’s functional unit or reference flow to the entire foreground system and following the identified consequences and constraints of a theoretical “supply chain—use—end-of-life” logic to M.Z. Hauschild and A. Bjørn


include identifying as minimum all product and waste flows (or their functional units) that cross the border to the background system29: 5:1. Primary market consequence and the size of the effect: First step— consider the primary market consequence and the size of the effect: 5:1:1. Identify the processes that are assumed to be additionally operated or taken out of operation as primary market consequence of the analysed decision and the directly related additional or reduced demand for a function/product, considering the following: 5:1:2. Size of effect:, EITHER 5:1:2:1. “small”—affecting only the extent of operation of one or more existing processes—the short-term marginal process(es) are the ones that should be assumed to be superseded, OR 5:1:2:2. “big”—resulting in additionally installed or de-installed capacity –> the long-term marginal processes are the ones that should be assumed to be superseded. 5:1:2:3


“big”—resulting in additionally installed or de-installed capacity –> the long-term marginal processes are the ones that should be assumed to be superseded. 5:1:2:3. The effect should generally be considered “small”, if the annual amount of additional demand or supply is smaller than the average percentage of annual replacement of capacity of the annual supply of that function or system in the given market; if that average percentage is over 5%, 5% should be used instead. Otherwise, it is “big”. The percentage is for orientation only and can be for a given case changed to be smaller or bigger upon the argumentation that the change in demand or supply is directly triggering changes in demand and not only via a marginal accumulative effect in contribution to the general market demand/signal. 5:2. Secondary consequences and constraints: Second step—consider secondary consequences and constraints: 5:2:1


5:2. Secondary consequences and constraints: Second step—consider secondary consequences and constraints: 5:2:1. If the size of the effect of the primary market consequence is “small”, check whether the secondary consequences and constraints in the market counteract the primary consequence (rebound), so that the net effect of the consequences is so small that it is not significantly different from being zero. In that case, the “short-term marginal” is best represented by the “average market consumption mix” of the processes/systems (but see next sub-provision). 5:2:2. For the specific case of multifunctionality, a key constraint occurs if the required co-function is an already fully used, dependent co-function of a joint production process (e.g


5:2:2. For the specific case of multifunctionality, a key constraint occurs if the required co-function is an already fully used, dependent co-function of a joint production process (e.g. copper ore mining with silver as dependent but fully used co-product, egg-laying chicken with the dependent co- “product” chicken being fully used for human food or animal fodder), as additional demand cannot be met by additional supply on a net basis. In that case, the required function/product will have to be produced in another 29It depends on the chosen background system model solution whether the processes of the background system also need to be individually identified or whether—if embedding the foreground system into an existing background system—this work has been already done.


way (e.g. for the above examples: silver from silver mine, or meat-chicken directly raised for food or fodder). 5:2:3. If the size of the effect of the primary market consequence is “big”, check next whether secondary consequences and market constraints counteract the primary consequence, so that the net overall effect is not “big” but “small”. 5:2:4. For those processes that are still facing “big” effects, explicitly consider that the affected processes might have been changed by the secondary consequences and constraints. This has to be analysed specifically to correctly identify the final effect/superseded processes. 5:3. Market situation and the cost-competitiveness: Third step—market situation and the cost-competitiveness of alternatives: 5:3:1. Market direction, EITHER 5:3:1:1. a “growing, stable, slightly declining market” (i.e. declining less than the average equipment replacement rate, OR 5:3:1:2. a “strongly declining market” (i.e


Market direction, EITHER 5:3:1:1. a “growing, stable, slightly declining market” (i.e. declining less than the average equipment replacement rate, OR 5:3:1:2. a “strongly declining market” (i.e. declining faster than the average equipment replacement rate). The above named average displacement rate in % is obtained by dividing 100 years by the average or typical life time of the capital equipment, expressed in years. 5:3:2. Based on this: analyse whether the extent of additional demand or supply for the effect “big” is changing the direction of the market, i.e. from a “strongly declining” market to a “slightly declining, stable, or growing” market OR vice versa. 5:3:3. If this is NOT the case, the affected processes/systems are always the “long-term marginal” processes/systems. 5:3:4. For all “small” and “big” cases in addition the cost-competitiveness of alternative processes/systems is relevant: 5:3:4:1


5:3:4. For all “small” and “big” cases in addition the cost-competitiveness of alternative processes/systems is relevant: 5:3:4:1. If the market is “growing, stable or slightly declining”, the “short-term marginal” (for “small” effects) and the “long-term marginal” (for “big” effects) are the most cost-competitive processes/systems. 5:3:4:2. If the market is “strongly declining”, the “short-term marginal” (for “small” effects) and the “long-term marginal” (for “big” effects) are the “least cost-competitive” processes/systems. 5:3:5. If in contrast the market direction IS changing, both the least and the most cost-competitive processes/systems are superseded and their specific type and share needs to be identified individually, drawing on the other provisions of this chapter. 5:4. Identifying the mix of processes/systems: Final step—identifying the mix of “short-term” or “long-term” marginal processes/systems: M.Z. Hauschild and A. Bjørn


5:4:1. In the consequential model, not only one single, short-term or long-term marginal process should be modelled but a mix of the most likely marginal processes, given the high uncertainty of market price forecasts and the often large differences of the environmental profiles among alternative marginal processes. To restrict the model to a single marginal process or system is only justifiable if there are no other, similarly cost- competitive processes or systems and hence the use of a single one is more appropriate. 5:4:2. The final amount of function (process or system) that is superseded shall be approximated considering the combined effect of primary and secondary consequences and constraints. Note that in case the market direction has changed as consequence of the analysed decision, the superseded processes are a specific combination of the least cost-competitive ones and partly the most cost. Further provisions, comments and recommendation on documentation (7.2.4.5) [ISO+] 6


Further provisions, comments and recommendation on documentation (7.2.4.5) [ISO+] 6. SHALL—Observe that: 6:1. Part-system and system–system relationships: These need special attention (e.g. for energy related products) and correct inventorying. Note that these cases are modelled identically in attributional modelling. 6:2. Individual processes within the background system: These may need to be identified as well when identifying significant issues or if required to meet the specific goal of the study. 6:3. Meet representativeness requirements: The requirements regarding technological, geographical and time-related representativeness shall be met. 7. SHOULD—Indirect land use changes: The appropriate way how to consider indirect land use changes should be developed. If done this shall be in line with the general provisions on consequential modelling. This is unless specific provisions would be published under the ILCD. Such provisions might be part of a future supplement. 8


This is unless specific provisions would be published under the ILCD. Such provisions might be part of a future supplement. 8. MAY—Schematic consequential model diagram: It is recommended using the system boundary scheme for overview. Schematic decision-consequence and flow diagrams of the most relevant consequences and marginal processes of the system(s) may be used to document the main identified consequences and constraints and the resulting resource bases, technologies, affected markets, etc. This can serve as basis for a data collection planning and later documentation.


Note again, that any exclusion of individual processes or activity types shall be justified using the cut-off criteria. In principle all processes are to be inventoried that are operated in consequence of the analysed decision. This includes in principle—depending on the system boundary—activities such as, e.g. 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, staff commuting and business travel, etc. 9. MAY—Initial processes’ description: It is recommended to also provide an initial description of the identified unit processes of the foreground system and the detailed functional units of those product and waste flows that link it to the background system


This should complement the documentation of the consequences and constraints and be completed with details during the iterations of the LCI work. Solving multifunctionality of processes and systems [ISO!] 10. SHALL—Subdivision and virtual subdivision: Subdivision and virtual subdivision shall be applied in preference to substitution.30 11. SHALL—Combined production: For cases of truly combined production, the determining physical causality (i.e. the first of the two steps of allocation under attributional modelling) equally applies analogously. 12. SHALL—Joint production: For joint production, substitution as a special case of system expansion is the preferred solution to multifunctionality. This shall be done as follows: 12:1. The same provisions shall apply as for general consequential modelling of the system. 12:2


This shall be done as follows: 12:1. The same provisions shall apply as for general consequential modelling of the system. 12:2. Note the specific constraint for already fully used, dependent co-products of joint production: since their production cannot be increased with that same multifunctional process/technology, their additional provision cannot be modelled. Instead, alternative routes need to be modelled for their supply. 12:3. If for the not required co-function functionally equivalent alternative processes/systems are operated/provided in a commercially relevant extent, the not required co-function shall be substituted with the mix of the superseded marginal processes (excluding the substituted process-route, if quantitatively relevant)


Differences in functionality between superseding and superseded function shall be considered by correction of the actually superseded amount of the superseded process(es) or by market price 30Observe that virtual subdivision shall not be done if it “cuts” through physically not separable joint processes, as this would distort the substitution. M.Z. Hauschild and A. Bjørn


correction of the superseded process(es)’ inventory (if the superseded amount is not known in sufficient detail). 12:4. If such alternative processes/systems do not exist31 or are not operated in a commercially relevant extent, the provided function in a wider sense should be used for substitution.32 Note that the substituted processes or products may also have secondary functions. This can theoretically lead to the problem of an eternally self-referring and/or very extensive, multiple extended system. As the amount of these secondary functions and their relevance within the overalls system goes down with each process step, this problem can be avoided/reduced by applying the cut-off rules. Substitution for multifunctional processes and systems in reuse/recycling/ recovery [ISO!] 13. SHALL—Recycling, recovery, reuse, further use: Substitution shall be applied for cases of recycling, recovery, reuse, further use: 13:1


SHALL—Recycling, recovery, reuse, further use: Substitution shall be applied for cases of recycling, recovery, reuse, further use: 13:1. Applying general rules to these cases: Substitution of products recycled or recovered from end-of-life product and waste treatment follows the same rules as for the general cases of multifunctionality. They shall be applied for all cases of waste and end-of-life treatment (i.e. “closed loop” and of “open loop—same primary route” and “open loop—different primary route”). Subdivision and virtual subdivision shall be applied in preference to substitution. 13:2. Specific aspects and steps (true joint process, interim processes to secondary good, recyclability, ...): Specific for reuse/recycling/recovery is that interim treatment steps occur more regularly and that often no truly equivalent alternative process/system exist.33 In this context, also the true joint process of the secondary good is to be identified


Finally, the steps of reuse/recycling/recovery need to be modelled explicitly until the secondary good is obtained that is actually superseding an alternative process/system. 31E.g. for wheat grain production, many refinery products, etc. 32E.g. as for NaOH apart from NaCl electrolysis, or if for a mobile phone the individual function SMS would not be available as commercially relevant, separate consumer product. NaOH provides the general function of neutralising agent and hence other, technically equivalent and competing neutralising agents, KOH, Ca(OH)2, Na2CO3, etc. can be assumed to be superseded. For the case of wheat grain and straw production: instead of straw, other dry biomass (e.g. Miscanthus grass, wood for heating, etc.) provides equivalent functions and can be assumed to be superseded. 33This is as secondary goods often have distinctly different properties from primary produced goods (e.g. recycled aged plastics vs


33This is as secondary goods often have distinctly different properties from primary produced goods (e.g. recycled aged plastics vs. primary plastics), what makes a clear assignment to the equivalent or most similar process/system more difficult.


The actual mix of superseded processes shall be identified for the given case and along the following steps: 13:2:1. The true joint process of the secondary good is that process step in the product’s life cycle that provides the good with the closest technical similarity to the secondary good; the thereby identified primary good shall not have a lower market value than the secondary good.34 13:2:2. The recyclability substitution approach shall be used for substitution. That implies that all interim waste management, treatment, transport, etc. steps are to be modelled and assigned to the analysed system including the step that is producing the valuable co-function (e.g. secondary metal bar). 13:2:3. The amount/degree of recyclability shall refer to the actually achieved recyclability, i.e. accounting for all kinds of losses, e.g. loss due to incomplete collection, sorting, recovery, during recycling processing, rejection, etc


accounting for all kinds of losses, e.g. loss due to incomplete collection, sorting, recovery, during recycling processing, rejection, etc. In short, the recyclability is the %35 of the amount of end-oflife product or waste that is found in the secondary good(s). For practical reasons and for long-living products this should per convention be the currently achieved recyclability for this product (or for new/projected products the achieved recyclability of comparable products in the same market). This can be another reference if the goal of the study explicitly relates to recyclability scenarios. 13:2:4. The superseded process(es)/system(s) shall be identified applying the general consequential modelling guidance as detailed in the above provisions.36 34This serves to avoid a potentially misleading upscaling of the superseded function's inventory in case of applying market value correction when correcting for the functional differences


35Note that this % needs to relate to the appropriate property and unit of the secondary good, e.g. Mass in kg for recycled materials, Lower calorific value in MJ for recovered energy, Pieces in number for reused parts, etc. 36That means that the earlier named constraint for already fully used, dependent co-products of joint production also applies here: since the production of e.g. a recycled metal as dependent co-product cannot be increased with that same multifunctional process/technology (i.e. by producing more e.g. metal goods, what is of course not happening), its additional provision via primary production cannot be assumed. Instead, alternative routes need to be modelled for the supply of the recycled metal. As stated for the general case, the determining co-product shall not be substituted


Instead, alternative routes need to be modelled for the supply of the recycled metal. As stated for the general case, the determining co-product shall not be substituted. The following example explains what that means and why for “closed loop” and “open loop - same primary route” cases nevertheless the primary production is to be substituted: Example: the determining co- product of primary and secondary metal is the primary metal. The secondary metal, after recycling, is the dependent co-product. If this one is fully used in the same or other products and from the perspective of the metal product made of primary metal, recyclability substitution is applied, substituting the secondary good by primary metal. From the perspective of the user of the secondary good “recycled metal”, the metal primary production shall not be substituted, but alternative ways of supplying the recycled metal shall be modelled


From the perspective of the user of the secondary good “recycled metal”, the metal primary production shall not be substituted, but alternative ways of supplying the recycled metal shall be modelled. This alternative way is, however—what makes this case apparently specific—the primary production of that metal as this is the only way to increase the availability of the required metal on a net basis. Hence in both cases, primary production is to be substituted, but for different reasons. M.Z. Hauschild and A. Bjørn


13:2:5. Also here not one marginal process should be used but the average inventories of several of the potential marginal processes. 13:2:6. For application-unspecific secondary goods, any reduced technical properties of the secondary good should be corrected in the accredited inventory by using the market price ratio (value correction) of the secondary good to the primary produced replaced function. 13:2:7. For application-specific uses of the secondary goods, sufficient functional equivalence with the superseded good shall be ensured and the credited inventory be reduced to the amount that is effectively superseded. In the case, this cannot be determined, the market price ratio (value correction) shall be applied as in the application-unspecific case. 13:2:8. Especially for the case of “open loop—different primary route” in addition it is to be checked whether commercially relevant alternative processes are operated


13:2:8. Especially for the case of “open loop—different primary route” in addition it is to be checked whether commercially relevant alternative processes are operated. Otherwise, the provisions for the general case of solving multifunctionality under consequential modelling shall be applied. 13:2:9. The other guidance aspects of this chapter on identifying the superseded processes (e.g. constraints, secondary consequences, etc.) apply analogously. Note that for scenario formation in comparisons, the various primary and secondary consequences and constraints should be varied jointly when defining “reasonably best case” and “reasonably worst-case” scenarios. In the inventory analysis, the treatment of multifunctional processes deserves special attention and should be decided before collecting the process data to ensure that the relevant processes are considered. A detailed guidance is given on this aspect in the ILCD Guidelines


A detailed guidance is given on this aspect in the ILCD Guidelines. Regardless the goal situation, the first choice is to subdivide a multifunctional process into monofunctional processes if that is possible. Avoiding allocation by subdivision or virtual subdivision (Provisions 7.9.2) Applicable to Situation C2. Applicable to cases of Situation A, B, C1 only if subdivision, virtual subdivision and substitution/system expansion were not possible or feasible, as identified along the specific provisions for these Situations. Applicable only to attributional modelling, unless in consequential modelling substitution is not possible or feasible. 1. SHALL—Analyse whether allocation can theoretically be avoided by subdivision: Investigate whether the analysed unit process is a black box unit process: does it contain other physically distinguishable sub-process steps and


is it theoretically possible to collect data exclusively for those sub-processes? Next, check whether subdivision can solve the multifunctionality of this black box unit process: can a process or process-chain within the initial black box unit process be identified and modelled separately that provides only the one required functional output? 2. SHALL—Aim at avoiding allocation by subdivision or virtual subdivision: Based on the outcome, the following steps shall be followed: 2:1. Subdivision: If it is possible to collect data exclusively for those included processes that have only the one, required functional output: inventory data should be collected only for those included unit processes. 2:2. Partial subdivision: If this is not possible (i.e. the analysed unit process contains multifunctional single operation unit processes that are attributed to the required functional output) or not feasible (e.g


the analysed unit process contains multifunctional single operation unit processes that are attributed to the required functional output) or not feasible (e.g. for lack of access or cost reasons): inventory data should be collected separately for at least some of the included unit processes, especially for those that are main contributors to the inventory and that cannot otherwise (e.g. by virtual subdivision—see later provision) clearly be assigned to only one of the co-functions. [ISO+] 2:3. Virtual subdivision: It should be checked whether it is possible by reasoning to virtually partly or fully subdivide the multifunctional process based on process/technology understanding. This is the case wherever a quantitative relationship can be identified and specified that exactly relates the types and amounts of a flow with at least one of the co-functions/reference flow(s) (e.g


the specific mechanical parts or auxiliary materials in a manufacturing plant that are only used for the analysed product can be clearly assigned to that product by subdividing the collected data). For those processes where this can be done, a virtual subdivision should be done, separating included processes as own unit processes. [ISO+] 2:4. Justify need for allocation and document potential distortion: If the preceding sub-steps are not possible and a real or virtual separation is not feasible, allocation is the approach that shall be applied (see next provision). In addition and only if subdivision is theoretically possible but was not performed, it should be demonstrated/argued at least via quantitative approximation or reasoning that the decision for allocation does not lead to relevant differences in the resulting inventory, compared to a subdivision


If it leads to relevant differences, the respective cases shall be documented and shall later be explicitly considered when assessing the achieved accuracy of data sets and when interpreting the final results of LCA studies, respectively. [ISO!] If subdivision is not possible, allocation is the choice for Situation C2 and for those cases in Situation A, B and C, where subdivision, virtual subdivision and substitution/system expansion was not possible or feasible. M.Z. Hauschild and A. Bjørn


Solving multifunctionality by allocation (Provisions 7.9.3) 1. SHALL—Share inventory between co-functions by allocation: If allocation is to be done, the environmental burden of the concerned processes shall be shared between the co-function(s) of the process or system by allocation. 2. SHALL—Differentiate multifunctional processes and multifunctional products: These two cases shall be differentiated [ISO!]. 3. SHALL—Two-step procedure for multifunctional processes: The following two-step procedure37 shall be applied [ISO!]: 3:1. First step and criterion “determining physical causality”: As first criterion, the “determining physical causal relationships” between each non-functional flow and the co-functions of the process shall be identified and used as allocation criterion. This relationship is the one that determines the way in which quantitative changes of the products or functions delivered by the system change the other inputs and outputs


This relationship is the one that determines the way in which quantitative changes of the products or functions delivered by the system change the other inputs and outputs. Within this step, process-related inventory flows (e.g. spontaneous NOx in incineration, consumption of auxiliary materials) should be differentiated from function (product) related inventory flows (e.g. the NOx from the nitrogen in the incinerated fuel, materials or parts ending up at least partly in the co-products). Note that often a combined, multiple allocation of the different non-functional flows to the co-functions is necessary, applying different criteria for the different flows. Note also that the preceding step of virtual subdivision is applying the same logic as physical causality allocation. 3:2


Note also that the preceding step of virtual subdivision is applying the same logic as physical causality allocation. 3:2. Checklist for “determining physical causality” criteria: If this is not possible or for any remaining inventory items, the following list gives guidance which criteria should be analysed by default whether they are the “determining physical causal relationship” to be used for allocation in different cases of co-servicing and co- production processes: 3:2:1. Services: • Goods transport: time or distance AND mass or volume (or in specific cases: pieces) of the transported good • Personal transport: time or distance AND weight of passengers 37The need is seen to develop supplementing practice-manuals in line with the ILCD and with explicit allocation- criteria/rules for main process and product groups, to further enhance practicability and reproducibility


This could follow the same general logic as applied when developing Product Category Rules (PCR) in support of Environmental Product Declarations (EPD).


• Staff business travel: added value of system • Staff commuting: added value of system • Retailing: time (duration) of shelf-life AND mass or volume of good • Storage and shelter, i.e. buildings and other three-dimensional infrastructure: time (duration) of use AND volume of good OR area occupied by the good • Storage and other functions provided by places and other two-dimensional infrastructure: time (duration) of use AND area occupied by the good • Transport and communication on roads, railways, pipes, cables and other one-dimensional infrastructure: time (duration) AND intensity (e.g. road wearing impact by vehicles of different weight) OR bandwidth of use


• Heating/cooling of space (keeping a temperature): time (duration of heating/cooling) AND area or volume heated/cooled (depending whether the space is used by area such as in offices, or by volume such as in staple storage halls or retail freezers) • Heating/cooling of goods (reaching a target temperature): heat capacity of good • Private administration services: person time or cost charged for admin services OR market value of sales • Public administration services: person time or cost charged for admin services OR number of cases serviced • Cleaning services (of objects of similar cleaning technologies): surface area cleaned (or as fallback option: time (duration) of cleaning) • Guarding services: share of product’s value among guarded products AND/OR the production/provision facilities’ value of the product among guarded site/object, depending what is the purpose of the guarding • Marketing services: share of product implicitly or explicitly addressed by marketing (e.g


corporate marketing: share of product’s value in corporate turnover) • Teaching/training services: person time (duration) of training AND number of individuals taught/trained • R&D services (of objects of similar R&D): person time OR cost charged for R&D services 3:2:2. Production processes: • Extraction processes: for process-related flows the market value, for product-related flows the specific physical properties of the co-products • Chemical conversion and waste processing (including incineration): quantitative change of the to-be-allocated flows in dependency of quantitative changes in the products or functions delivered by the system. If unknown: the chemical or physical properties that determine the amount of the other flows M.Z. Hauschild and A. Bjørn


• Manufacturing (including physical transformation processes) and mechanical waste processing: length, surface, volume, or mass OR number of items OR time of processing • General processes by other capital goods’ input directly to multifunctional processes (e.g. the processing machines themselves, but not buildings, etc.): time (duration) of use OR mass, volume, length of produced good 3:3. Justify selection from checklist: In the case alternatives are given in the above provisions, the chosen alternative shall be concisely justified. 3:4. Justify other criteria: If another specific relationship is applied that is not listed above, that choice shall be concisely justified including explaining why none of the default provisions is applicable or the most suitable ones, along the guidance given in the text. 3:5. Justify non-existence of determining physical causality: If a “determining physical causal relationships” does not exist (i.e


3:5. Justify non-existence of determining physical causality: If a “determining physical causal relationships” does not exist (i.e. it is not in the above list and no other can be identified), this shall be concisely justified. Only in that case the second allocation step should be applied (see below); otherwise, the resulting lack of accuracy and potential distortion is to be documented and explicitly be considered in the results interpretation. 4. SHOULD—Second step and criterion “market price”: As second, general allocation criterion for multifunctional processes, the market price of the co-functions should be applied. If this is done, the price shall refer to the specific condition and at the point the co-functions leave or enter38 the multifunctional unit process or are provided. This means for processes that the known, calculated or approximated market price shall relate to, e.g


This means for processes that the known, calculated or approximated market price shall relate to, e.g. the specific technical characteristics in quantity and quality such as purity, compressed or not, packaged or not, etc. as well as bulk or small amounts, etc. at the point it leaves the process. If this cannot be done, the resulting lack in accuracy and potential distortion of the results shall be documented and be considered in the results interpretation. 5. SHOULD—Two-step procedure for multifunctional products (e.g. consumer products): The following two-step procedure shall be applied: [ISO!] 5:1. First step and criterion “determining physical causality”: As first criterion, the “determining physical causal relationships” between each non-functional flow and the co-functions of the product should be identified and applied. The above guidance for multifunctional flows can be applied analogously. 5:2


The above guidance for multifunctional flows can be applied analogously. 5:2. Use virtual subdivision principle to perform explicit allocation: As an initial step, analogously as above for multifunctional processes, the logic of virtual subdivision should be applied to virtually subdivide the multifunctional product. 38“Enter” in case of waste and end-of-life treatment services.


5:3. Second step and criterion “QFD” or “market price”: 5:3:1. Preferred second criterion—Quality Function Deployment: If the above cannot be done, the Quality Function Deployment (QFD) should be used to identify the relevance of the co-function from the user’s perspective. If a QFD does not exist and cannot be developed (e.g. due to cost or timing reasons), the second, general allocation criterion of “market price” of equivalent products for the single co-functions can and shall be applied. 5:3:2. Alternative second criterion—market price: If the QFD is not feasible, allocation by market price should be done in analogy to the preceding case for multifunctional processes. For products, the representative price of products that provide an equivalent to each single function should be used to allocate among the co-functions of the multifunctional product. [ISO+] 6


For products, the representative price of products that provide an equivalent to each single function should be used to allocate among the co-functions of the multifunctional product. [ISO+] 6. SHALL—Attributional modelling of reuse, recycling and recovery: The following provisions shall be applied in attributional modelling of recycling and related: [ISO!] 6:1. Follow general rules for multifunctionality, observing specific aspects: Allocation of products from end-of-life product and waste treatment shall apply the same general rules as other cases of multifunctionality, with two specific aspects: 6:1:1. Dealing with waste and end-of-life products of negative market value that generate secondary goods: Specific is firstly that in case the market value of the end-of-life product or waste is below zero (e.g. soiled post-consumer packaging waste), the appropriate process step at the system boundary to the next life cycle is to be identified, i.e. where the allocation is to be applied


soiled post-consumer packaging waste), the appropriate process step at the system boundary to the next life cycle is to be identified, i.e. where the allocation is to be applied. This process step is that one where the valuable co-function is created after one or more initial treatment processes have taken place (e.g. sorted plastic fraction of the above waste). 6:1:2. True joint process to be identified: Specific is secondly that for end-oflife products and waste the true joint process is to be identified, which is separated by various, e.g. manufacturing steps from the step where the end-of-life product occurs: 6:1:2:1. For waste or end-of-life products with a market price equal or above zero, the true joint process is that process earlier in the life cycle of the system, where the good (e.g. an aluminium bar) is technically approximately equivalent to the secondary good of the waste or end-of-life product (e.g. aluminium scrap from construction demolishing)


an aluminium bar) is technically approximately equivalent to the secondary good of the waste or end-of-life product (e.g. aluminium scrap from construction demolishing). Note that for “open loop —different primary route” recycling this step might necessarily involve abstraction to the basic properties of the two products. These two products that have been identified as described above are then considered co-products of the true joint process. 6:1:2:2. For waste and end-of-life products with a market value below zero, the true joint process is that one, which produces that product that is about equivalent to the first valuable product that is produced from the initial waste treatment processes, as described in the preceding provision. These M.Z. Hauschild and A. Bjørn


two products that have been identified as described above are then considered co-products of the true joint process. 6:1:2:3. In the case of multiple functions from the waste or end-of-life product (e.g. a complex consumer product is discarded for recycling of its many materials and for energy recovery), there is each one true joint process for each of them that shall be identified. 6:2. Provisions: The following provisions can be derived that shall be applied, differentiating between waste/end-of-life products with negative and positive market value: 6:2:1. Negative market value: If the market price of the waste/end-of-life product is below zero: 6:2:1:1. The waste/end-of-life management/treatment processes until excluding the process where the pre-treated waste crosses the “zero market value” border (i.e. when a process is generating a function with positive market value) shall be allocated exclusively to the first system


when a process is generating a function with positive market value) shall be allocated exclusively to the first system. In the case the exact process step or the waste and/or secondary good properties cannot be clearly identified, the resulting lack of accuracy shall be reported and later be considered in the results interpretation 6:2:1:2. Subsequently, the two-step allocation procedure shall be applied between the valuable secondary good and its co-product from the true joint process (i.e. see the next provision). This involves a second, additional allocation exclusively of the inventory of that process step that has produced the first valuable product after the initial waste treatment steps, as follows: 6:2:1:3. The inventory exclusively of the process step that produces a valuable product (secondary good) should be allocated with the market value criterion between the secondary good(s) and the (potentially pre-treated) waste/end-of-life product that enters this process step


The burdens that are allocated to the pre-treated waste/end-of-life product belong to the first system, the ones assigned to the secondary good(s) to the second system (s). Note that the market value of the pre-treated waste/end-of-life product is below zero and that hence the absolute value of its (negative) market price39 should be used when calculating the allocation key; the rest of the allocation calculation is the same. 6:2:1:4. After that, the two-step allocation is applied between the valuable secondary good and the true joint process, as follows in the next provision, i.e. analogous to the case when the waste or end-of-life product have a positive market price. 6:2:2. Market value equal or above zero: If the market price of the waste/endof-life product is equal or above zero, the two-step allocation procedure shall directly be applied between the process step that generates the waste or end-of-life product and the true joint process


The following procedure shall be applied: 39E.g. if the market value/gate fee is “−1 US$” this would be “1 US$”.


6:2:2:1. As first criterion, the “determining physical causal relationships” between each non-functional flow and the co-functions of the process shall be identified and applied. This is worked out as follows: 6:2:2:2. Two sub-cases are to be differentiated: the first one is where the secondary good is undergoing none or limited changes in the inherent properties (e.g. metal recycling, fibre recycling) and the second one is where it undergoes relevant changes in the inherent properties (e.g. energy recovery from mixed polymer waste). The first sub-case applies to all “closed loop” and “open loop—same primary route” situations. The second sub-case applies to all “Open loop—different primary route” situations. 6:2:2:3


The first sub-case applies to all “closed loop” and “open loop—same primary route” situations. The second sub-case applies to all “Open loop—different primary route” situations. 6:2:2:3. For the first sub-case, the total number of cycles and the therefrom derived total amount of uses (considering the loss at each cycle; concept see text) is determined and used for allocation across the many uses including the initial production up to the true joint process. In result the following formula can be developed for an infinite number of loops (considering the losses at each loop): 6:2:2:4


In result the following formula can be developed for an infinite number of loops (considering the losses at each loop): 6:2:2:4. e 1⁄4 P þ W ð Þ  1  r ð Þ þ R  r with e average LCI per unit of material, part, or energy carrier r average recycling rate [0...1), incorporating both collection efficiencies and processing efficiencies P LCI of primary production per unit of material, part, or energy carrier W LCI of final waste management per unit of discarded material, part, or energy carrier R LCI of effort for reuse/recycling/recovery per unit of material, part, or energy carrier 6:2:2:5. The allocation formula is to consider in addition the change in the inherent properties of the secondary good. 6:2:2:6. If the above cannot be done because information that is required for applying the formula cannot be obtained or at least approximated, the second step of “market value” allocation needs to be applied. In that case, it must be detailed and justified why the above cannot be applied


In that case, it must be detailed and justified why the above cannot be applied. It shall be also demonstrated that the market value allocation is not disfavouring any competitor product, if the results are intended to be used for comparisons. 6:2:2:7. For the second sub-case, i.e. where the recycled/recovered/reused good undergoes relevant changes in the inherent properties, the true joint process is the one along the production chain that produces the minimum required M.Z. Hauschild and A. Bjørn


quality40 of the good to generate the secondary good. (E.g. in case of soiled low value LDPE post-consumer plastic waste that is incinerated to recover the energy: As the LDPE is incinerated and basically only the lower calorific value is of interest, the minimum required good is even before the production of the LDPE—the crude oil (incl. transport to the country of LDPE production) is meeting the minimum requirements in this case.) Based on this, the general two-step allocation procedure shall be applied between the secondary good and the function(s) or the true joint process. 6:2:2:8. If several functions are generated from the waste/end-of-life product (e.g. different metals recovered), this shall be done individually with each of the true joint processes. 7


6:2:2:8. If several functions are generated from the waste/end-of-life product (e.g. different metals recovered), this shall be done individually with each of the true joint processes. 7. SHALL—System-wide consistent application of allocation: Consistency shall be ensured as far as possible, using the same allocation criteria for the different co-functions of any specific process and across all similar processes within the system boundary. Otherwise, the lack of consistency and its effect on accuracy, precision and completeness shall be considered when stating the quality of a data set or when interpreting the results of an LCA study, respectively. 8. SHALL—100% rule: The sum of the inventories allocated to all co-products shall be equal to the inventory of the system before allocation was done


8. SHALL—100% rule: The sum of the inventories allocated to all co-products shall be equal to the inventory of the system before allocation was done. 37.4.2 Planning Data Collection The planning of the data collection has the purpose of balancing the invested effort against the relevance of the respective data and information in order to avoid wasting time on collecting high quality data that have a low relevance for the LCA results and/or spend too little time on collecting high quality data where it is highly relevant for the results. Planning data collection (Provisions 7.3) 1. SHALL—Identify newly required, study-specific unit processes: Identify for which processes of the analysed system new, study-specific unit processes have to be developed with producer or operator specific primary and secondary data. This is typically the case for the entire foreground system (including for those parts of existing or planned contractual relationships)


This is typically the case for the entire foreground system (including for those parts of existing or planned contractual relationships). The use of technical process or flow diagrams is recommended. 2. SHALL—Average and generic data: Identify for which parts of the analysed system the use of average or generic LCI data sets is more appropriate. Note that 40Note that this provision ensures fulfilling the ISO 14044 provision on considering the change in inherent properties of the secondary good.


for a given case, average or generic data may be more accurate, complete and precise also for some processes of the foreground system. If such will be used, this shall be justified. 3. MAY—Identify data and information sources: It is recommended to systematically identify sources for the required data and information. This includes considering working for the background system primarily with LCI results or with unit process data sets, which both have advantages and disadvantages that are for the given case to be evaluated. Combinations are possible if the data is consistent. Among the LCI data sources, primary and secondary sources can be differentiated. Guiding principle should be the availability and quality of the most appropriate data. Working with well-documented and already reviewed data sets is recommended. This supports a correct use of the data sets, a sound documentation of the analysed system and its review. [ISO+] 4


Working with well-documented and already reviewed data sets is recommended. This supports a correct use of the data sets, a sound documentation of the analysed system and its review. [ISO+] 4. MAY—SI units: It is recommended to aim at collecting data in the Système international d’unités (SI) units, to minimise conversion efforts and potential errors. [ISO+] Note that SI units shall be used for reporting. 5. SHOULD—Multi-annual or generic data to be preferred? Evaluate along the goal of the study whether multi-annual average data or generic data should be preferred over annual average data as better representing the process/system. This applies for processes with strong inter-annual variations (e.g. agriculture; producer-specific data in general), to ensure sufficient time-related representativeness. [ISO+] 6. MAY—Relevance-steered data collection: It is recommended to steer the effort for data collection by the relevance of the respective data and information


[ISO+] 6. MAY—Relevance-steered data collection: It is recommended to steer the effort for data collection by the relevance of the respective data and information. Building on existing experience that sufficiently reflects the analysed process or system and that is of high quality is an essential guide. Product Category Rules (PCR) and product-group specific guidance documents can represent this experience. The following is meant to help focusing data collection efforts. The initial data quality and data set quality requirements as identified in the scope definition may need to be fine-tuned/adjusted in subsequent loops as follows: [ISO+] 6:1. For the identification of quantitative LCI data quality needs, determine/estimate the accuracy, completeness and precision of the LCIA results that is required by the intended application (e.g. to allow identifying significant differences among compared alternative products). 6:2


to allow identifying significant differences among compared alternative products). 6:2. Translate these requirements to related requirements at the level of elementary flows by taking into account the impact potentials of the individual elementary flows and by disregarding the uncertainties/inaccuracies associated with the characterisation factors. M.Z. Hauschild and A. Bjørn


6:3. Use these requirements on the elementary flows to determine the maximum permissible uncertainty, inaccuracy and incompleteness of the overall inventory of the to-be-collected or purchased processes’ or systems’ inventories. Note that this includes systematic uncertainties from LCI methods and models applied and from assumptions made when setting up the system model. 6:4. Use this information as indicative guidance on quality requirements in the collection or purchase of inventory data (i.e. unit process or LCI results and similar data sets). For secondary LCI data sets, it is recommended to consider the following additional quality aspects: appropriate documentation, the use of compatible elementary flows and nomenclature, methodological consistency and a completed qualified external review


37.4.3 Constructing and Quality Checking Unit Processes The following provisions have the purpose to guide the construction of unit processes and ensure that the process data is appropriate to represent the performance of the model that it represents. Types of input and output flows to collect (Provisions 7.4.2.4) 1. SHALL—Types of input and output flows: Quantitative data of all relevant inputs and outputs that are associated with the unit process shall be collected/modelled, as far as possible. Where not possible, the gaps shall be documented and if they cannot be overcome be considered when reporting the achieved data quality and when interpreting results of a study. These flows typically include, if relevant for the modelled process/system: 1:1. Input of “consumed” products (i.e. materials, services, parts, complex goods, consumables, etc.), as product flows. 1:2. Input of wastes (only in case of waste servicing processes), as waste flows. 1:3. Input of resources from nature (i.e


1:2. Input of wastes (only in case of waste servicing processes), as waste flows. 1:3. Input of resources from nature (i.e. from ground, water, air, biosphere, land, etc. and with possible further sub-compartment specifications as required by the impact assessment methodology to be applied), as elementary flows. 1:4. Emissions to air, water and soil (with possible further sub-compartment specifications as required by the impact assessment methodology to be applied), as elementary flows 1:5. Other input and output side interventions with the ecosphere (if required by the applied LCIA methods), as elementary flows.


1:6. Output of wastes (e.g. solid, liquid, gaseous waste for waste management within the technosphere41), as waste flows. 1:7. Output of valuable goods and services provided by the process, as product flows. Data and information types for specific, future and generic data sets (Provisions 7.4.2.5) 1. SHOULD—Raw data types: Raw data types that should be used for the process, as required: [ISO+] 1:1. Measured data collected by/at process operators should be preferred if possible and appropriate. Measurements are not only physical measurements of, e.g. emissions but also other specific information for the operated process such as, e.g. bills and consumption lists, stock/inventory changes and similar. 1:2. Element composition and energy content of product and waste flows. This data should later be inventoried as flow property information for these flows to support interim quality control, review and improving data quality. 1:3


This data should later be inventoried as flow property information for these flows to support interim quality control, review and improving data quality. 1:3. Various other data can be helpful (also for crosschecks) or even necessary (to fill gaps). These are, e.g. recipes and formulations, part lists, patents, process engineering models, stoichiometric models, process and product specifications and testing reports, legal limits, market shares and sizes, data of similar processes, BAT reference documents, etc. 1:4. Use stage information: For modelling the use stage of consumer products and initial waste management, it is recommended to use surveys and studies that analyse the average or typical user behaviour to complement product specifications and user manuals. Information provided in product category rules (PCR) can be supporting. Representativeness regarding operation conditions (Provisions 7.4.2.7) 1


Information provided in product category rules (PCR) can be supporting. Representativeness regarding operation conditions (Provisions 7.4.2.7) 1. SHALL—Full operational cycle of the process, if required: The collected inventory data for a specific process shall as far as possible and required to meet the goal represent the full operational cycle of the process. This includes all quantitatively relevant steps such as, e.g. preparation, start, operation, closure, standby and cleaning as well as maintenance and repair of the process/system and under normal and abnormal operating conditions. This is unless the data set is meant to represent only a partial cycle. The above applies analogously also to services. The achieved representativeness of the data shall be documented. 2. SHOULD—One full year as data basis: For measured data of operated processes, data for at least one full year should be used as basis for deriving representative average data


2. SHOULD—One full year as data basis: For measured data of operated processes, data for at least one full year should be used as basis for deriving representative average data. A sufficient number of samples should be taken and the uncertainty be considered when reporting the precision. 41The emissions resulting from waste that is directly discarded into the environment shall be modelled as part of the LCI model, with the processes considered to be part of the technosphere. M.Z. Hauschild and A. Bjørn


3. SHOULD—For parameterised processes: The mathematical relations should represent the relevant changes of the inventory in dependency of the influential parameters, which can be, e.g. technical, management, or others. This can include quantitative and qualitative relationships between inventory flows. [ISO+] Note that the mathematical model and its relevant assumptions and limitations later will need to be documented as well. Guidance is also given with hints on how to perform quality control of the collected data for a unit process. Interim quality control (Provisions 7.4.2.11) Many of the following provisions on interim quality control are only recommendations, but the same controls may be part of a subsequent mandatory external review. General approach 1. SHALL—Validity check: A validity check of the collected data shall be performed during the process of data collection and unit process development, to confirm that the data is in line with the goal and scope requirements


The following provisions provides related operational recommendations on this requirement: 2. MAY—Interim quality control as review along “interpretation” provisions: For the interim quality control on the unit process level, it is recommended to apply the data quality related technical aspects of the critical review regarding the scope and methods of review together with the guidance on interpretation (especially significant issues, sensitivity check, completeness check and consistency check). These steps can, however, be done in a less formal way. Among others, the following may be done at this point: [ISO+] 2:1. All relevant flows? Does the unit process inventory include all relevant product, waste and elementary flows that would be expected based on, e.g


All relevant flows? Does the unit process inventory include all relevant product, waste and elementary flows that would be expected based on, e.g. the input of processed materials, of the nature of transformations occurring in the process, and/or based on experience gained with similar processes? Reflect the required technological, geographical and time-related representativeness. 2:2. Flow amounts are proportionate? Are the amounts of the individual flows and of the chemical elements, energy and parts in the input and output in expected proportion to each other? 2:3. Support control by impact assessment: Controls may also be based on impact assessment results for the process as well as for the whole system. They may reveal errors in the inventory results through showing unexpected


high or low values of contributing elementary flows. Compare the LCIA results with data of the same or similar processes/systems from other sources to identify possible problems. Make sure the other sources are of high quality and especially high completeness. 2:4. Method consistency? On the system level, carefully check that methods have been applied consistently. This especially applies if combining data from different sources. 2:5. Follow up on discrepancies: Check and explain or correct any observed discrepancies in the inventory data by consulting additional data sources or technical experts for the analysed process. 2:6. Report on findings: It is recommended providing for the unit process data set at least a brief internal quality control report on the above findings. 2:7. Reflect findings in data set quality indicators: Make sure that the data set documentation appropriately describes the process and the identified accuracy, precision and completeness as well as any limitations


Obtaining better unit process data 3. SHALL—Dealing with initially missing data: The potential importance of initially missing data shall be checked in the following way and relevant gaps shall be filled if possible and as detailed below: [ISO!] 3:1. SHOULD—Identify relevance of initially missing data: A reasonable worst case or at least conservative value for the missing data should be used in a first screening to see if they may influence the overall results of the LCI/LCA study. This reasonable worst case or conservative value may be derived by inference from knowledge of similar or related processes or from correlation or calculation from other flows of the process. This includes identifying and inventorying flows that were initially not known to occur in the analysed process but that could not be excluded entirely. 3:2


This includes identifying and inventorying flows that were initially not known to occur in the analysed process but that could not be excluded entirely. 3:2. SHOULD—Dealing with relevant, initially missing data: If this screening shows that the missing data may be of importance, in further iterations of the LCA work it should be attempted to first identify whether the flow is actually occurring in the analysed process and if so to get the yet missing data. As second option sufficiently good estimates should be obtained. As third option, if also that is not possible, the gap should be kept and reported. (Details see separate provisions more below): 3:3. SHALL—Filling data gaps with estimates of defined and minimum quality: 3:3:1 SHALL—For each newly modelled unit process any initially missing data should be documented in a transparent and consistent way