This means that the provision of secondary resources or parts is another function of the system that generates the waste or end-of-life product: The impacts associated with the secondary goods166 are to be shared among the systems that use them. 165 This is also referred to as „shared processes“. 166 The term „secondary good“ is here used as umbrella term for recycled materials, recovered energy, reused or further used parts, etc., i.e. for any (secondary) function that is produced from a waste of end-of-life product.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Note that the following chapter provides guidance on solving multifunctionality in attributional modelling only, as the corresponding task in consequential modelling has been addressed already in the chapter 7.2.4 on identifying and describing processes. This was necessary as in consequential modelling this step directly affects the processes to be included in the model, i.e. is not a subsequent step as in attributional modelling. Solving multifunctionality Under the (historically developed) heading “Allocation”, ISO 14044:2006 presents a hierarchy of different approaches to this multifunctionality problem167. In chapter 6.5.3 the ISO hierarchy and the different LCI method approaches have been detailed and illustrated

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


In chapter 6.5.3 the ISO hierarchy and the different LCI method approaches have been detailed and illustrated. At the same time it was found that the approach for solving cases of multifunctionality has to be in line with the goal of the LCI/LCA study, especially the decision-context(s), as consistency with the goal is a guiding principle of ISO-LCA. This means that there is no free choice between allocation and substitution, but the goal of the LCI/LCA study defines which approach is theoretically appropriate: The way of how to handle multifunctional processes is closely related to the applied LCI modelling framework, being consequential or attributional (see chapter 6.5.2) and it had to be made in accordance with this choice. The present chapter relates to attributional modelling, i.e. for Situation C2 and for those cases where substitution is not possible or feasible; see the respective provisions for the other Situations


for Situation C2 and for those cases where substitution is not possible or feasible; see the respective provisions for the other Situations. This means that the first step is the subdivision of multifunctional black box unit processes to mono-functional single operation unit processes and thereby cutting free the actually required production processes, avoiding the need for allocation. If this is principally impossible or other reasons make it practically impossible, allocation (partitioning) is the next possible step (see chapter 6.5.3). 7.9.2 Avoiding allocation by subdivision of virtual subdivision (Refers to aspects of ISO 14044:2006 chapter 4.3.4.2) Multifunctionality can occur on two levels: single operation unit processes that principally cannot be further sub-divided for data collection purposes (e.g. the electrolysis process of NaCl electrolysis, yielding NaOH solution, Cl2 and H2 as co-products) and black box unit processes that can be further sub-divided (e.g


the electrolysis process of NaCl electrolysis, yielding NaOH solution, Cl2 and H2 as co-products) and black box unit processes that can be further sub-divided (e.g. a manufacturing line with several kinds of polymer packaging produced as co-products). In the first example, allocation is the appropriate approach under attributional modelling to solve the multifunctionality. In the second example, first choice is to subdivide the concerned "packaging manufacturing" process into its included specific processes for the different packagings, if it is possible in this way to separate the production of the analysed good or service from that of the co-function(s); see Figure 8. Chapter 7.4.2.2 provides the detailed guidance for subdivision. In the case subdivision is not feasible due to lack of access to data or resourcerestrictions, virtual subdivision can in many cases fully or partly single out those inventory items that exclusively relate to the required function


This renders the inventory more accurate, as only the possible remaining inventory items are to be allocated; it also improves the reviewability of the data. Chapter 7.4.2.2 provides some more details also on virtual subdivision. 167 As the hierarchy covers other approaches than only allocation, clearer and more appropriate would hence be the encompassing title „Solving multifunctionality of processes“.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision 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 (see 6.5.4). Applicable only to attributional modelling, unless in consequential modelling substitution is not possible or feasible


I) SHALL - Analyse whether allocation can theoretically be avoided by subdivision: Investigate whether the analysed unit process is a black box unit process (concept see Figure 7): 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 provide only the one required functional output? II) SHALL - Aim at avoiding allocation by subdivision or virtual subdivision: Based on the outcome, the following steps shall be followed: II.a) 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


II.b) 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. 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+] II.c) Virtual subdivision: It should be checked whether it is possible by reasoning to virtually partly or fully sub-divide 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. Chapter 7.4.2.2 provides additional details on the approach. [ISO+] II.d) 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 chapter). 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!] Note that virtual subdivision can also improve the basis for allocation, with more accurate results.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results 7.9.3 Solving multifunctionality by allocation (Refers to ISO 14044:2006 chapter 4.3.4) 7.9.3.1 Overview (Refers to aspects of ISO 14044:2006 chapter 4.3.4.1) Allocation criteria are to be identified for those cases where allocation (and not substitution) is required to be applied to solve multifunctionality of not further subdividable unit processes168. The allocation criteria are identified in a two-step procedure, starting with and strongly building on the physical causality, as equally recommended in ISO 14044:2006. To summarise this two-step procedure that is detailed in the following subchapters:  As first criterion other “determining physical causal relationships” between each nonfunctional flow and the co-functions of the process are to be identified and applied169


Part of this is to use the virtual subdivision approach to assign flows to the co-functions, as much as possible.  Flows that cannot be allocated in this way are to be allocated using a second, general allocation criterion, which is the market value of the co-functions in the specific condition and at the point they leave the process (or enter it as e.g. in case of waste and end-oflife treatment services). While some of the rules and examples for the first criterion are obvious, this is not always the case. Some effort is therefore made here to clearly specify and illustrate this procedure to ensure reproducibility in practice, starting with simple and obvious cases. A special issue is the waste and end-of-life product recycling that requires additional steps, why it is addressed in a separate annex 14


A special issue is the waste and end-of-life product recycling that requires additional steps, why it is addressed in a separate annex 14. 7.9.3.2 First criterion “Determining physical causality” (Refers to aspects of ISO 14044:2006 chapter 4.3.4.2) Determining physical causality The determining physical causality can relate to both goods and services. This expression is composed of three components: causality, physical, and determining: - “Causality” relates to the question whether the existence and quantity of a nonfunctional flow is caused by the respective co-function. - “Physical causality” means that this cause is to be a physically determinable one including an extensive physical flow property (e.g. especially the energy content (enthalpy, lower and upper calorific value, exergy, entropy), mass, volume, length/distance, specific element/substance/material/part content, number of pieces (number of items, individuals, particles/moles))


In the case of services, the physical property is typically to be used in combination with time/duration of the service, as 168 Note however, that allocation may also need to be applied in cases where at first sight and from a limited, theoretical decision-consequence perspective system expansion / substitution would be the correct approach. 169 The need is seen to develop supplementing practice-manuals for main 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 Declaration (EPD).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results this is its mostly applicable reference unit. I.e. two or more properties together are causally determining. - “Determining”, finally, relates to the fact that often several causal physical relationships exist of which only one or a combination of two is determining the existence and quantity of a non-functional flow. The determining physical causality is identified by answering the question “Is there a specific function that the non-functional flow performs for one or more of the co-products and can I quantify the extent of this function via a physical criterion?”


And: “If so, are there other non-functional flows that occur quantitatively or partly as direct or indirect consequence of the initially identified, physically caused non-functional flow?” It is important to note that other than found often in practice, there is no need to apply the same physical causality criterion to all non-functional flows. In contrast is this rather seldomly correct: the physical causality is often specific for a flow, same as the underlying reality is specific. This applies to black box unit processes, where specific processes with specific inventory items relate to the analysed function. Note that this also applies to multifunctional single operation unit processes where specific input products (e.g. a chemical such as Chlorine), entirely end up only in one of the co-products (e.g. the chlorinated chemical as one of the co-products). That means that often a combined, multiple allocation of the different non-functional flows of the inventory is necessary


the chlorinated chemical as one of the co-products). That means that often a combined, multiple allocation of the different non-functional flows of the inventory is necessary. Principle of applying the virtual subdivision logic within the physical causality The logic of virtual subdivision is closely related to the one of determining physical causality: Both aim at identifying which amount of which inventory items are exactly related to which co-product, reflecting the physical relationships among them. E.g. all input products that are physically embodied in any of the co-produced goods170, can be directly assigned to them. This was illustrated in the chapters 7.9.2 and 7.4.2.2 on virtual subdivision with the example of different parts that enter a manufacturing line of trucks and each end up only in the specific trucks that use this specific part


Embodied goods (product flows) An obvious example for the embodiment of goods are components that are assembled to more complex goods, e.g. the specific components that enter a multiple production line of tailor-made trucks and end up in a specific truck are assigned to the truck they are build into. In this example the process is partly virtually sub-divided along a qualitative understanding, assigning the individual input product flows to the receiving co-product. Note that this step is equivalent to the earlier addressed virtual subdivision of unit processes along a qualitative technical understanding of that process. This can even be applied in cases of physically not further sub-dividable single operation unit processes. A similar example is an injection-moulding machine that processes different polymers and where each specific polymer input flow is assigned to that specific moulded part that is made of it (see also chapter 7.4.2.2 on subdivision and virtual subdivision)


In other cases the same material that directly enter a process can be physically found in several co-produced goods. E.g. the round wood that is entering a sawmill, is equally found in the co-produced beams, planks, slabs, wood chips, and sawdust. The amount of round170 Physical embodiment can obviously not relate to services.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results wood product flow that is embodied in the respective co-product is assigned to its inventory171. Components of the determining physical causality The next step is the determining physical causality in a wider sense. Care must be taken to identify exclusively the causal and not other, non-causal physical relationships (and subsequently identify which is the determining one): In mining of e.g. granite as functional material, granite tiles are produced together with granite gravel as valuable co-product. The mining itself and transport of the raw blocks to the plant would need to be allocated by mass to both co-products, as physically required for their production. The cutting of the blocks into the tiles and remaining gravel as cuttings is equally physically required for both co-products


The cutting of the blocks into the tiles and remaining gravel as cuttings is equally physically required for both co-products. The cutting process is however determining only for the coproduct tiles, as it relates to its specific characteristics of smoothly cut surfaces, while not to the granite gravel. A similar example is a gold-ore extraction process where the applied mining chemicals are physically mixed with the whole ore, but are determining only for the extracted gold (and other metals that are extracted by that chemical) but not to the rocks that come out of the process, even though they may be valuable co-products with use in road construction. The preceding gold-ore mining and grinding processes again would be physically required for both co-products, same as in the above granite example172


The preceding gold-ore mining and grinding processes again would be physically required for both co-products, same as in the above granite example172. Key for correctly identifying the determining physical causality is the understanding of the causalities that links each of the co-products with the respective other non-functional flow that needs to be allocated. The following paragraphs show how this determining physical causality is identified for different types of non-functional flows and for both co-produced goods and co-services. Illustrative examples serve to clarify and further guide their application: Allocation of good’s inputs to co-services: For co-services, the use of any product, component, consumable material etc. input that is used exclusively to provide the respective co-service‟s function is obviously a determining physical relationship


input that is used exclusively to provide the respective co-service‟s function is obviously a determining physical relationship. Note that this step is identical to the earlier described process of a virtual subdivision of a unit process along a qualitative understanding of that process: in an example a retailing shop may selling among other goods frozen food. The production and operation of the freezer would then be allocated exclusively to the goods that are sold via display in the freezer. (Regarding the question how to allocate the freezer among the various goods sold from the freezer see more below). Allocation of good’s inputs to co-produced goods: For co-products, in many cases the used input products, energy carriers, etc. can equally often largely be allocated based on the specific function they perform in relation to the individual co-products


can equally often largely be allocated based on the specific function they perform in relation to the individual co-products. For example, electricity used in the chlor-alkali-electrolysis is used to split the water and results in production of the energy-rich hydrogen and chlorine gases as 171 Note that other than it may appear, this is NOT equivalent to allocation by mass, as loss of material to nonvalued outputs is not yet addressed and would need to be allocated in a subsequent step. 172 One could argue that the high effort for deep underground mining of gold-ore is not really necessary to obtain some low-value gravel as co-product. However, this consideration is a consequential one and looking as costs as a cause. Attributionally, it is necessary (physical causality) to get the ore from that depth to produce that specific gravel.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results co-products. The enthalpy of H2 and Cl2 is hence an appropriate allocation criteria for the used electricity, reflecting the determining physical relationship of bringing energy into the coproducts. In the similar example of the Haber-Bosch-Synthesis of ammonia, natural gas is the energy source to capture nitrogen from air to produce the ammonia. CO2 is the coproduct (if captured, e.g. for a subsequent step of urea production, and not vented). The energy of the natural gas is exclusively found in the ammonia (apart from energy-losses due to process inefficiency), while not at all in the CO2. Again enthalpy serves to allocate the inventory of the product natural gas flow to the ammonia co-product


Again enthalpy serves to allocate the inventory of the product natural gas flow to the ammonia co-product . Allocation of service inputs to co-produced goods - introduction: The input of many services can be allocated to the co-products by the relative duration they are used in combination with the determining physical causal relationship. Parallel and serial services can be differentiated: Allocation of service inputs to co-produced goods - parallel services: Parallel services serve at the same time in parallel several co-products and that relate to the co-products in a similar way. Examples are the services that storage facilities, transport equipment, manufacturing halls, and production equipment provide173. E.g. for transport the transport time is one factor (which is equivalent to the transport distance, of course, which is typically used in practice and factually equivalent for co-transport)


E.g. for transport the transport time is one factor (which is equivalent to the transport distance, of course, which is typically used in practice and factually equivalent for co-transport). In addition it would need to be checked whether the weight of the co-transported goods or their volume is the limiting physical causality that determines how much of the transport service is used. Duration in combination with either mass or volume is to be used as allocation criterion. Whether mass of volume is determining would be figured out by evaluating whether the given transport case is limited by the mass of the goods (i.e. the truck is fully loaded by mass) or whether more mass could be added, but the truck is full by volume


the truck is fully loaded by mass) or whether more mass could be added, but the truck is full by volume. Coming back to the example of the freezer used in retail, the time the good is on average stored in the freezer plus the determining physical factor (here we could conclude that this is the volume174 of the individual good) is used to allocate among the many goods sold via the freezer175. Another example is the service input flows of heating, lighting, and providing a hall structure for several laptop assembly lines: the duration of assembly of the different coproduced laptops would be the allocation criterion for the three named inputs. Among the possible physical criteria (mass, volume, pieces), the piece of laptop could be singled out as 173 It is argued to be clearer to understand such products from the perspective of the service they provide, e.g. the service of providing a hall structure, heating and lighting for an assembly line, rather than as an good


the service of providing a hall structure, heating and lighting for an assembly line, rather than as an good. Other than a material or part that is physically ending up in the product, all these buildings etc. only provide a service for the co-production. For this reason they also typically need other allocation criteria (e.g. duration of use of a storage hall, lighting, etc.) compared to the element, mass or energy content as allocation criteria of goods that physically end up in the co-products. In fact are many such infrastructures also operated under leasing contracts („productservice systems“). 174 While the heat capacity of the good also plays a role, it might be found that the main energy consumption is for compensating the loss through the surface of the freezer including its opening on top or door by the customer. Let aside a few more complex considerations of the shape of the good/package, i.e


Let aside a few more complex considerations of the shape of the good/package, i.e. how well it fills the freezer, and how cold it arrives at the freezer, the volume might still be the most appropriate criterion in most cases. 175 Note that the precision with which such storage times and volumes must be determined, depends on the relevance of the freezer storage for the whole product system analysed. In the iterative approach to LCA and after an initial, rough approximation of such numbers, it is identified how relevant this process is and only if relevant the storage time and volumes need to be identified in more detail.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results limiting, if we assume that the specific mass or volume do not determine the size of the hall, lighting etc. Another example on services: the inventory of operating a law firm, providing legal services for different customers would be allocated by the duration with which the customerassistances use the law firm. Regarding the physical criterion (imaginable: mass, volume, pieces) we would probably agree on the pieces (i.e. number) of customers and not their mass or volume. A final example on transport services: In the case of allocating passenger-transport by plane it gets more tricky, as both mass and number of passengers are in fact limiting (due to maximum take-off weight and the number of available passenger seats; any remaining weight would be available for additional freight transport)


However, in the average situation neither seats nor the available total weight are used to capacity. Hence we need to allocate between the number of passengers and the weight of the freight in any case. How this? The plane's fuel consumption and related emissions (looking only at that part of the inventory) is determined - for a given route - by the plane's aerodynamics (which is determined largely by its outer size and shape) and additionally by the total starting weight. Any additional passenger will only affect the starting weight, same as any additional kg of freight. Hence, the determining physical causality is simply the mass. This example also shows the problem of applying economic allocation: in that case a low fare seat would have very little impact compared to a regularly fared seat in the same class, while both have the same contribution to the fuel-related inventory


If however the parallel service relates to the co-products of the investigated production system in a clearly different way, and the unit process cannot be sub-divided obtaining exclusively non-multifunctional processes, the general allocation criteria is to be applied. Allocation of service inputs to co-produced goods - serial services Serial services perform the same action to the co-products one after the other (e.g. a paint shop painting different metal parts one after the other). Strictly, these processes are all subdividable, with separate measurements. However, as discussed earlier this may not be easily feasible in practice: If the serial service performs its service in the same intensity over time, it can be allocated simply by the duration it is carried out one after the other for the different coproducts. In other cases, a physical characteristic of the serviced co-products can be used (e.g


In other cases, a physical characteristic of the serviced co-products can be used (e.g. regarding the paint shop example this would be the surface of metal parts to be painted. In the case of cleaning services, equally the surface of the cleaned floor would be the determining criterion, given same/similar floor types). The intensity of the serial service may change in intensity over time or the serviced co-products have relevantly different characteristics (e.g. cleaning of both carpet and PVC floors). In that case it might be not possible to identify a suitable physical relationship that quantitatively characterises this intensity. In consequence, subdivision would be necessary unless the differences could be demonstrated to be less relevant and the application of the second, general allocation criterion would be possible


In consequence, subdivision would be necessary unless the differences could be demonstrated to be less relevant and the application of the second, general allocation criterion would be possible. Allocation of goods and services inputs to co-produced goods - criteria list The following list gives provisions of which criteria should by default be used for allocation in different cases of co-servicing and co-production: Services:  Goods transport: time or distance AND mass or volume (or in specific cases: pieces) of the transported good


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Personal transport: time or distance AND weight176 of passengers  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 good177  Transport and communication on roads, railways, pipes, cables, and other onedimensional 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 fall-back 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 176 If an average passenger is aimed at, this can be expressed also per individual passenger by using an average weight. 177 Area and duration of actual coverage allocated by assigning to relative contribution if this can be directly determined (e.g. for different processing plants of an integrated chemical site, or for different crops and perannual trees in an agro-forestry system). If the area is jointly covered (e.g. in mixed cropping, or for co-products from same chemical reactor) this is not possible, and the general allocation criterion is to be applied. Not actually physically covered land that however forms integral part of the analysed process system (e.g


Not actually physically covered land that however forms integral part of the analysed process system (e.g. field sides, or unused areas between plants of a chemical site) is equally allocated using the general criterion. Land area that is temporarily not used (e.g. in the time between subsequent crops or between closure and reconstruction of industrial facilities on the same area of land) is generally allocated to the first product system. This also applies to e.g. restoration activities (e.g. fallow-times, site-remediation, etc.); note that these are equivalent also to service inputs into the first product system.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results 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  Manufacturing (including physical transformation processes) and mechanical waste processing: length, surface, volume, or mass OR number of items OR time of processing  Recycling, energy-recovery, reuse: see specific provisions in chapter 7.9.3 and details on allocation of waste inputs see annex 14.4


 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 In the case alternatives are given above, the chosen alternative shall be concisely justified. Exceptions from the above alternatives shall be justified by explaining why none of the provisions is applicable and concisely justifying the one that has been chosen instead, along the guidance given in the text178. Equally, if criteria are applied for other then the above listed type of services, there selection shall be concisely justified in analogous logic. 7.9.3.3 Second (general) criterion “Economic value” or QFD (Refers to aspects of ISO 14044:2006 chapter 4.3.4.2) Overview For flows that cannot be allocated with the first criterion, a second general criterion is to be applied


Allocation of co-functions and comparisons of multifunctional products For the special case of comparisons of multifunctional products with not sufficiently similar functional units (e.g. printer-fax-photocopier with printer-fax-photocopier-scanner) the Quality Function Deployment (QFD) approach should be considered to allocate parts of the inventory to the not common functions and render the compared products sufficient. QFD helps transforming customer needs ("Voice of customer") into engineering characteristics of a product or service, prioritizing each function (and characteristic that support the function) into development targets for the product or service. For details, see the specific literature. In the context of LCA, QFD can be interpreted as identifying the relevance the different co-functions of a multifunctional product are assumed to have for its average user


In the context of LCA, QFD can be interpreted as identifying the relevance the different co-functions of a multifunctional product are assumed to have for its average user. The QFD should be used in preference to allocation by market price, if physical causality cannot solve the multifunctionality. This applies especially to the production stage; for the use stage, the market price as service provision cost might serve (however excluding person / operating time costs, what will often be difficult to determine). Similarly, the market price of 178 In subsequent work on sector or product group specific guidance documents (e.g. similar as Product Category Rules (PCR) used in Environmental Product Declarations (EPD)) the above rules should be further interpreted and specific guidance provided.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results the individual devices might be a suitable criteria for the market price allocation for production and end-of-life stage. However, if the co-functions have clearly different environmental profiles (e.g. a very different use stage electricity consumption for the heater for the laser print compared to potentially much less for the FAX and scan functions), the QFD alone would lead to distorted results. To overcome such cases, the allocation among the co-functions would need to be more differentiated (or the distortion would need to be reported and reflected in the results interpretation). It might also be necessary to re-evaluate the possibility of virtual subdivision (see chapter 7.9.2)


It might also be necessary to re-evaluate the possibility of virtual subdivision (see chapter 7.9.2). The foreseen involvement of interested parties and product users would then need to achieve a best attainable consensus on the allocation key as part of the critical review process. Figure 24 illustrates the concept of QFD. Figure 24 Quality Function Deployment (QFD) of complex products as an approach for obtaining as allocations factors the relative relevance of functions for the product users. Allocation for multifunctional processes This second criterion is the economic value of the co-products at the point (i.e. at plant / service provider) and in the condition (e.g. not purified / technical quality) and amount (e.g. bulk) as they are provided by the multifunctional process. As economic value the specific market price shall be used


not purified / technical quality) and amount (e.g. bulk) as they are provided by the multifunctional process. As economic value the specific market price shall be used. If the co-products are not traded at that point of allocation and with their specific characteristics, the market price has to be derived combining production cost information and the market price of the further processed, packed, transported etc. coproduct. Any additional steps of transport, conditioning, packaging etc. are to be considered to make sure the economic value used for allocation actually reflects the value of each coproduct at the point and in the condition where it is delivered. E.g. in case of wheat grain production with straw as a co-product and obtained via a combined harvester, the relevant economic value of the grain and straw is at the field directly


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results after the combined harvest. As the grain is transported, cleaned, stored, potentially dried and maybe also packed before sold, these additional sets and the related costs are to be subtracted from a large scale/bulk market price. Similarly costs for the baling and transport of the straw are to be excluded from the market price to obtain the relevant economic value at harvest point. Such additional steps can substantially influence the price and distort the allocation, especially for low value/mass goods. Frequent errors: Wrong type/reference of market value A frequent error in this type of allocation is to apply the wrong point of allocation


Frequent errors: Wrong type/reference of market value A frequent error in this type of allocation is to apply the wrong point of allocation. This is most often the case and most easily illustrated for the case of using market price as criterion: in the case of allocating electricity and heat from a combined power plant the most appropriate / correct point of allocation would be inside the plant, with e.g. 3 US-cents per 1 kWh electricity and 1 US-cent per kWh heat. An often found but wrong point of allocation is the reception of the electricity and steam at the final consumer with a price of e.g. 30 US-cents per 1 kWh electricity and 5 US-cents for each kWh heat delivered. As this includes the product-specific heat pipelines and related losses and electricity voltage conversion down to 110 V and loss during delivery to final consumer etc., it distorts the results, in the given example the allocation ratio electricity/heat changes from 3 to 1 to 6 to 1


Examples to illustrate the difficulty to work with physical causality alone An example may be wheat cropping with wheat grains and wheat straw being the coproducts. The allocation of the used fertiliser and nitrate emissions among these co-products might be based on their specific protein content, reflecting how much of the nitrogen goes into producing either of them. For the tractor's fuel consumption and the occupied land, the allocation criterion is however less clear; the market price or the mass could be considered. Another example may be the co-transport of goods by truck where the weight of the individual good influences the fuel consumption and emissions of the transport process and where the allocation of the inventory results between the transported goods would be based on the ratio between their weights. Note however that in case the volume of the goods is the limiting factor (e.g


Note however that in case the volume of the goods is the limiting factor (e.g. where very light goods such as insulation materials are transported and the trucks capacity by weight is not reached), the situation gets more complex: the good's volume would be the criterion to allocate the inventory of driving the empty truck (i.e. the base inventory), while the goods‟ mass would be the appropriate allocation criteria for the additional fuel consumption and emissions due to the additional weight of the carried goods. A municipal waste incinerator treating a mixture of materials in household waste is an example where allocation based on different causal physical relationships between input and output is a useful approach: The emission of cadmium in the flue gas could be allocated between the materials in the co-incinerated waste streams according to their contents of cadmium


The product flow of the recovered heat could be allocated to the co-incinerated waste materials according to their upper calorific value. On the other hand, the causal relationship behind the formation of Nitrogen oxides (NOx) in the flue gas is more complex: A part of the NOx is process-related formed from oxidation of a small amount of the atmospheric Nitrogen (N2) in the incineration air. Another part of this emission stems from the oxidation of the N-content of the waste materials, which calls for the use of another allocation criterion or the combination of more than one. A similar difficulty occurs when allocating dioxin emissions from co-incineration to the different wastes, as both carbon and chlorine sources are needed but also the way the process is operated influences the final concentration, hence there are several potential allocation criteria to be evaluated for appropriateness.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Outlook: waste fee adjusted market value It is noted that using the direct market value for allocation is somewhat distorting, as also waste and end-of-life products with a negative market value can have a "value": this is if the value is higher (i.e. the waste fee is less negative) than the default option of e.g. discarding the waste or end-of-life product without benefit, e.g. in landfilling without energy-recovery. Such an adjusted allocation criterion for market price allocation considering the costdifference to the waste fee cost instead of the direct market value zero, still needs to be developed and practice tested. If so, it might be adopted in sector or product group specific guidance documents or Product Category Rules (PCRs). If these would be developed in an ILCD compliant way (e.g


If so, it might be adopted in sector or product group specific guidance documents or Product Category Rules (PCRs). If these would be developed in an ILCD compliant way (e.g. review, stakeholder involvement) such a different market price allocation can be applied here instead. Reuse, recycling, and recovery For co-production of products from waste that initially has a market value below "0" (e.g. electricity from waste incineration) please see also 14.4.1.3, and for the specific provisions for end-of-life products for reuse/recycling/recovery that have a positive market value please see chapter 14.4.1.2. Provisions: 7.9.3 Solving multifunctionality by allocation These provisions are applicable only for Situation C2 and for those cases in Situation A, B and C, if subdivision, virtual subdivision and substitution/system expansion was not possible or feasible, along the given provisions (see 6.5.4)


I) 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. (7.9.3.1) II) SHALL - Differentiate multifunctional processes and multifunctional products: These two cases shall be differentiated [ISO!]. (7.9.3.2) III) SHALL - Two-step procedure for multifunctional processes: The following two-step procedure179 shall be applied [ISO!]: (7.9.3.2) III.a) 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. Within this step, process-related inventory flows (e.g


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 179 The need is seen to develop supplementing practice-manuals in line with the ILCD and with explicit allocationcriteria/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).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation allocation. III.b) 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 coproduction processes: III.b.i) 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  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 twodimensional 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 fall-back 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


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation for R&D services III.b.ii) 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  Manufacturing (including physical transformation processes) and mechanical waste processing: length, surface, volume, or mass OR number of items OR time of processing  Recycling, energy-recovery, reuse: see specific provisions in chapter 7.9.3 and details on allocation of waste inputs see annex 14.4.  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 III.c) Justify selection from checklist: In the case alternatives are given in the above provisions, the chosen alternative shall be concisely justified


III.d) 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. III.e) 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 (7.9.3.3). IV) 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


IV) 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 enter180 the multifunctional unit process or are provided. 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. V) SHOULD - Two-step procedure for multifunctional products (e.g


V) SHOULD - Two-step procedure for multifunctional products (e.g. consumer products): The following two-step procedure179 shall be applied (7.9.3.2): [ISO!] V.a) First step and criterion "determining physical causality": As first criterion the 180 "Enter" in case of waste and end-of-life treatment services.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation “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. V.b) 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. V.c) Second step and criterion "QFD" or "market price": V.c.i) 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 (see below). V.c.ii) 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


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. (7.9.3.3) [ISO+] VI) SHALL - Attributional modelling of reuse, recycling, recovery: The following provisions shall be applied in attributional modelling of recycling and related (the corresponding detailed explanations are found in annex 14.4): [ISO!] VI.a) 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: VI.a.i) 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 postconsumer 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). VI.a.ii) 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 (for the concept see Figure 29): VI.a.ii.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. a aluminium bar) is technically approximately equivalent to the secondary good of the waste or end-of-life product (e.g


a 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


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation 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. VI.a.ii.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 two products that have been identified as described above are then considered coproducts of the true joint process. VI.a.ii.3) In the case of multiple functions from the waste or end-of-life product (e.g


VI.a.ii.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. VI.b) Provisions: The following provisions can be derived that shall be applied, differentiating between wastes / end-of-life products with negative and positive market value: VI.b.i) Negative market value: If the market price of the waste / end-of-life product is below zero (see also Figure 33 and explanations in annex 0): VI.b.i.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. VI.b.i.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: VI.b.i.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


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation (negative) market price181 should be used when calculating the allocation key; the rest of the allocation calculation is the same. VI.b.i.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-oflife product have a positive market price. VI.b.ii) 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 (details see annex 14.4.1.2): VI.b.ii.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: VI.b.ii.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


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. VI.b.ii.3) For the first sub-case, the total number of cycles and the therefrom derived the 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) (detailed steps see annex 14.4.1): VI.b.ii.4) r R r W P e * ) 1( *  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 181 E.g. if the market value / gate fee is „-1 US$“ this would be „1 US$“.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results Provisions: 7.9.3 Solving multifunctionality by allocation energy carrier VI.b.ii.5) The allocation formula is to consider in addition the change in the inherent properties of the secondary good. VI.b.ii.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. 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. VI.b.ii.7) For the second sub-case, i.e


VI.b.ii.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 quality182 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 (provisions see more above). VI.b.ii.8) If several functions are generated from the waste / end-of-life product (e.g


VI.b.ii.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. VII) 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. VIII) 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. 182 Note that this provision ensures that the ISO 14044 provision on considering the change in inherent properties of the secondary good.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results 7.10 Calculating LCI results (Refers to aspects of ISO 14044:2006 chapter 4.3.3) Overview Depending on the level of aggregation that is required for the intended applications, the inventories of all included unit processes are scaled in relation to their share in the overall product system and are aggregated over e.g. sub-assemblies, over life cycle stages, or over the whole product system183. When the inventory calculations are performed, it is important to be consistent in applying the same calculation procedures throughout the LCI/LCA study. All quantitatively relevant interim products and wastes generated inside the system are to be completely modelled, if being co-products substituted or allocated, depending on the applied LCI method approach


The final LCI results hence shall represent exclusively the product prescribed by the functional unit. If the system has been modelled completely, the resulting aggregated inventory exclusively contains elementary flows (e.g. resources as inputs and emissions as outputs) that cross the system boundary in addition to the product or products, which are defined by the functional unit. One exception is radioactive waste, which can stay in the inventory as no agreed LCI modelling framework of its long-term management is available yet. Often also other co-products and wastes in however insignificant amounts can remain in the inventory, in line with the cut-off criteria. For reporting, these can be removed from the inventory (upon approval by the reviewer regarding their quantitative irrelevance). Depending on the goal and scope of the LCI/LCA study, scenario analysis and uncertainty calculations should also be performed


Depending on the goal and scope of the LCI/LCA study, scenario analysis and uncertainty calculations should also be performed. This especially applies to product comparisons and more so for future strategy comparisons. Averaging data See chapter 7.7. Provisions: 7.10 Calculating LCI results Applies to all types of deliverables of the study, while for unit process and partly terminated system data sets as deliverables only to quantify the achieved completeness and precision, as they need to be evaluated from the system's perspective. I) SHALL - Apply calculation procedures consistently: The same calculation procedures shall be applied consistently throughout the analysed system(s) when aggregating the processes within the system boundary for obtaining the LCI results. II) SHALL - Calculate and aggregate the inventory data of the system(s): (See also 7.8


II) SHALL - Calculate and aggregate the inventory data of the system(s): (See also 7.8. If the model is correctly prepared, the first two following sub-bullets can be skipped): II.a) Determine for each process within the system boundary how much of its reference flow is required for the system to deliver its functional unit(s) and/or reference 183 Note that the calculation of LCI results is also required when developing unit process data sets as deliverables of the LCA work, as it serves, together with subsequent characterisation to quantify the overall completeness and approximate the overall uncertainty of the data set per impact category. If normalisation and weighting are included in the definition of the cut-off rules, also these are to be applied.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 7 Life Cycle Inventory analysis - collecting data, modelling the system, calculating results flows(s) (i.e. the extent to which the process is involved in the system). II.b) Scale the inventory of each process accordingly. This way it relates to the functional unit(s) and/or reference flow(s) of the system. Note that if parameterised process data sets are used in the system model, the parameter values are to be set before scaling and aggregation. II.c) The correctly scaled inventories of all processes within the system boundary shall be aggregated (summed up) for that system. II.d) If the intended application of the results requires a location non-generic impact assessment (as identified in 6.7.5), aggregation of the elementary flows above the required location type or level (e.g


the level of a single site/plant, a region, a country, an environmental sub-compartment, etc.) should be avoided in the LCI results calculation. The same applies for other differentiations (e.g. of environmental sub-compartments or archetypes of emission situations) if those are required for the intended application and impact assessment methods to be used. [ISO+] II.e) If the disaggregated data cannot be publicly disclosed (e.g. for confidentiality reasons), it is recommended to foresee performing the impact assessment on the disaggregated level and providing the LCIA results together with the aggregated LCI results. [ISO+] Note that also in this case (as in all cases) the reviewers shall have (at least confidential) access to all underlying data


[ISO+] Note that also in this case (as in all cases) the reviewers shall have (at least confidential) access to all underlying data. III) SHOULD - Ensure that reference flow(s) is/are only product and waste flow(s): Note that after aggregation, the reference flow(s) is/are the only product and/or waste flow(s) that should remain in the LCI results inventory, with two exceptions: III.a) For partly terminated systems: The inventories of selected products and/or waste flows were left out of the system boundary - typically intentionally - and the flows are kept in the inventory. Note however that for the purpose of quantifying the achieved completeness via the cut-off rules of environmental impact, also these selected product and waste flows are to be considered via integrating the inventories of the respective production and waste treatment processes. III.b) For radioactive waste and waste in underground waste deposits (e.g


III.b) For radioactive waste and waste in underground waste deposits (e.g. mine filling): These waste flows can be kept in the inventory for direct use in interpretation (see chapter 7.4.4.2). IV) SHALL - Highlight and explicitly consider remaining non-functional product or waste flows: Any product and waste flows that remain in the inventory and that are nonfunctional flows shall be highlighted in the report and/or data set: Either they require to be modelled when later using the data set (e.g. by complementing the data set with a yet missing background LCI data set for e.g. a specific chemical consumed, or modelling the management/treatment of a specific waste). Or this gap / missing data needs to be explicitly considered in subsequent interpretation and conclusions drawn.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results 8 Life Cycle Impact Assessment - calculating LCIA results (Refers to ISO 14044:2006 chapter 4.4) 8.1 Introduction and overview (Refers to aspects of ISO 14044:2006 chapter 4.4.1, 4.4.2, and 4.4.3) General Life Cycle Impact Assessment (LCIA) is the phase in an LCA where the inputs and outputs of elementary flows that have been collected and reported in the inventory are translated into impact indicator results related to human health, natural environment, and resource depletion. It is important to note that LCA and the impact assessment is analysing the potential environmental impacts that are caused by interventions that cross the border between technosphere and ecosphere and act on the natural environment and humans, often only after fate and exposure steps


The results of LCIA should be seen as environmentally relevant impact potential indicators, rather than predictions of actual environmental effects. LCA and LCIA are equally distinct from risk based, substance specific instruments. See also the related notes in the guidance document “Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators”


See also the related notes in the guidance document “Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators”. Overview LCIA is composed of mandatory and optional steps, as reflected also by the subchapters:  Based on classification and characterisation of the individual elementary flows, which is usually done by LCIA experts that provide complete sets of LCIA methods for use by LCA practitioners184 (see separate guidance document "Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators"), the LCIA results are calculated by multiplying the individual inventory data of the LCI results with the characterisation factors (8.2)  In a subsequent185, optional step, the LCIA results can be multiplied with normalisation factors that represent the overall inventory of a reference (e.g


a whole country or an average citizen), obtaining dimensionless, normalised LCIA results (8.3)  In a second optional step these normalised LCIA results can be multiplied by a set of weighting factors, that indicate the different relevance that the different impact categories (midpoint level related weighting) or areas-of-protection (endpoint level related weighting) may have, obtaining normalised and weighted LCIA results that can be summed up to a single-value overall impact indicator (8.4). Note that a weighting set always involves value choices. 184 Note that the development or variation/adjustment of LCIA methods is never done by the vast majority of normal LCA practitioners, but by special LCIA experts, whose LCIA methods and factors the LCA practitioners use and rely on


For this reason and also to avoid that LCIA methods are selected after the LCI results have been calculated and based on interests, the aspects of selecting or adjusting LCIA methods are entirely addressed in the scope chapter 6.7. This current chapter refers hence exclusively to the calculation of the LCIA results. 185 ISO 14044 also foresees an optional "Grouping" step. No specific recommendations are given here. If it is decided to apply a grouping step, the ISO 1444 provision can be applied.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results The LCIA phase prepares additional input for the interpretation phase of the LCI/LCA study. Impact assessment, normalisation and weighting for applying cut-off criteria Note, that even if the application of the LCI/LCA study does not require to report any impact assessment results (e.g. when developing a cradle-to-gate LCI results data set for a specific product for customer information), it is still relevant to perform an impact assessment of the data set as part of the LCI/LCA study: This is because of the iterative approach to LCA where the achieved level of completeness and precision (cut-off criteria) of the LCI data set is to be judged on its LCIA results


The LCIA results are hence also the basis for a sensitivity analysis to support identification of the main contributing elementary flows and of the processes causing them, as part of the stepwise improvement of the inventory data. This may include the use of normalisation and weighting, if it has been decided to implement the cut-off criteria in relationship to the normalised and weighted LCIA results. LCIA in comparative studies In comparative LCA studies, an impact assessment must be performed in addition, calculating the final LCIA results that are an important component of the basis for the interpretation phase, and the conclusions and recommendations must be based on the outcome of the LCIA results. Expressing LCIA results LCIA results of the individual impact categories are typically expressed as equivalent values if this is a midpoint level indicator (e.g. kg CO2-equivalents for the Global Warming Potential GWP) or damage values for endpoint level indicators (e.g


kg CO2-equivalents for the Global Warming Potential GWP) or damage values for endpoint level indicators (e.g. DALYs for Human health, PDF*m2*a for Natural environment / Species diversity impacts)186. Note that the formal measurement units of the above three examples are kg, a, and m2*a, respectively, while for better communication the initially named expressions are most widely used. 8.2 Calculation of LCIA results (Refers to aspects of ISO 14044:2006 chapters 4.4.2 and 4.4.3) Calculating LCIA results Using the LCIA methods as identified in the scope phase187 of the LCI/LCA study (chapter 6.7.2), now the LCIA results are to be calculated. While ISO is not addressing the development of LCIA methods in any detail, it formalises the link between the inventory elementary flows and the impact assessment factors, as follows: The impact assessment at midpoint and/or endpoint level is performed by first assigning the elementary flows to the one or more relevant categories of impact


This step is called “Classification” (see also Figure 15). Then the inventory results for the individual elementary flows are usually linearly188 multiplied with the relevant impact factors from the applied LCIA methods; this step is called “Characterisation”. Details are provided in the separate guidance 186 For definitions and details see the separate document "Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators". 187 See that chapter for the explanation why this shall be done in the scope phase and not only after LCI data collection and modelling. 188 Certain LCIA methods use non-linear relationships for the characterisation.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results document "Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators" on the development and selection of Life Cycle Impact Assessment models and factors. In LCA practice, these steps are not regularly done by LCA practitioners, but this is part of the work towards developing LCIA methods. The practitioner is however responsible to ensure that the inventory elementary flows are correctly linked with the LCIA factors (see more below) and - together with LCIA experts - to derive or develop missing impact factors if potentially relevant for the study (details see chapter 6.7.4). The resulting characterized indicator results can be summed up within each impact category. The resulting collection of aggregated indicator results is the characterized impact profile of the product, i.e. its LCIA results


The resulting collection of aggregated indicator results is the characterized impact profile of the product, i.e. its LCIA results. No comparison across impact categories As the LCIA results per impact category have different units, they cannot directly be compared to identify which are most relevant. Equally it cannot be summed up. Ensure a correct link between inventory and impact factors Databases within LCA software typically provide elementary flows that have been classified and characterised and thereby “linked” with the LCIA methods. The practitioner is however responsible to ensure that the inventory elementary flows are correctly linked with the LCIA factors. This in any case applies for elementary flows that were added by the practitioner during data collection and for newly applied LCIA methods. The work of correctly linking inventory and impact factors is supported by using the same nomenclature and flow data sets, e.g


The work of correctly linking inventory and impact factors is supported by using the same nomenclature and flow data sets, e.g. the ILCD nomenclature and related reference elementary flows. Frequent errors: Incomplete LCIA factor assignment to elementary flows In LCA databases of diverse origins of the data (e.g. combined by the software/database provider or growing over the years at the practitioner) typically have a number of elementary flows that should carry a characterisation factor in the covered LCIA methods, but don‟t have it assigned. That means the impact assessment is incomplete and – depending on the relevancy of the gaps – leads to wrong results and conclusions. Some of the main “candidates” for such omissions and possible solutions189 are as follows. The related provisions are found in the referenced chapters (here below the provision status is given only for orientation): - Combined ores (e.g


The related provisions are found in the referenced chapters (here below the provision status is given only for orientation): - Combined ores (e.g. “Lead-zinc ore; 2.5 % Pb, 1.8 % Zn" as "Resources from ground” that were created by the practitioner or imported from the database developers). Possible solution: ° a) (not permissible190:) Calculate the resource depletion factors of the single elements, scale them to the respective element contents of the flow, sum them up and assign the resulting factor to that flow. ° b) (shall:) Avoid specific ore resource flows by splitting the ore flow up into the 189 These cases and possible solutions have been considered and are in line with the ILCD „Nomenclature and other conventions“ guidance, the chapter on overarching methodological issues (annex 7.4.3) and are implemented in the related ILCD reference elementary flows


190 "not permissible" refers here to reporting for external use, as the respective flows would not meet the provisions of the "Nomenclature and other provisions" (see separate document) and/or the "Overarching method provisions for specific elementary flow types" (see chapter 7.4.3).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results flows of the contained chemical elements and use the respective elementary flows that already have impact factors assigned (i.e. for the above example to “Lead" as "Resources from ground” and “Zinc" as "Resources from ground” and a complementary "Inert rock" as "Resources from ground” for the mass balance.) Note that for some ores the compound may need to be inventoried (e.g. Rock salt (NaCl); details see chapter 7.4.3.6.2. - Composed emissions such as e.g. salts (e.g. Ammonium nitrate, while characterisation factors exist for the contained ions Ammonium and Nitrate). Possible solution: ° a) (not permissible:) Calculate the correct factor stoichiometrically (or other method, as appropriate) and assign to the flow. ° b) (shall:) Inventory the components as separate elementary flows (e.g. "Ammonium" and "Nitrate" for the above example)


° b) (shall:) Inventory the components as separate elementary flows (e.g. "Ammonium" and "Nitrate" for the above example). See also chapter 7.4.3.3 on when to split elementary flows of salts depending on their water solubility. - Process-type specific (composed) emissions such as “Diesel engine off-gas” etc., which cannot be usefully addressed in impact assessment and which typically have no impact factor at all and that shall not remain in the inventory. Possible solution: ° a) (should:) Inventory the specific substances emitted if data is available or ° b) (may) Estimate the composition by using technology-specific information on emission-composition or default break-down tables (documenting assumptions made) and inventory the individual substances emitted. - Newly user-created flows of e.g. emissions that even may have a factor in the used LCIA method but that were not provided with the LCA database package or software


- Newly user-created flows of e.g. emissions that even may have a factor in the used LCIA method but that were not provided with the LCA database package or software. Possible solution: ° First check whether the package is complete; obtain the missing factors. For flows that were newly created by the user, it should be verified that it is not actually an existing flow but named with an e.g. trivial name or an alternative chemical name. CAS numbers help in verifying this. - Emissions to sub-compartments or at specific locations for which no specific impact factor is available. Possible solution: ° a) (recommended) Avoid use of such flows unless specific factors are available in the applied LCIA method for all quantitatively relevant elementary flows, or ° b) (shall) Assign the impact factor of the same elementary flow of the parent compartment (e.g. the impact factor for "Nitrate" as "Emissions to freshwater" is also assigned to "Nitrate" as "Emissions to lakes")


the impact factor for "Nitrate" as "Emissions to freshwater" is also assigned to "Nitrate" as "Emissions to lakes"). See the separate document "Nomenclature and other conventions" for applicable default compartments. - Sum-indicators such as “Metals” and measured indicators, which cannot be usefully addressed in impact assessment and which typically have no impact factor at all and that shall not remain in the inventory. Possible solution: ° a) (should) Inventory the individual substances (e.g. for the sum-indicator "Metals" the individual "Lead", "Iron", etc. metals), if composition information is available, or ° b) (may) Estimate the composition by using technology-specific information on


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results emission-composition or default break-down tables (documenting assumptions made) and inventory the individual substances emitted. See chapter 7.4.3.2 for permissible sum-indicators. - Unspecified “Biomass”, “Renewable energy”, “Unspecified emissions”, etc. elementary flows. Possible solution: ° a) (should) Inventory the individual components if data is available, or ° b) (may) Estimate the composition by using technology-specific information on composition or default break-down tables or a typical generic case (documenting assumptions made) and inventory the individual substances emitted. Note: Check also whether the respective flow is potentially relevant (along process-specific worst-case assumptions) and remove it from the inventory if clearly not relevant in line with the applied cut-off rules


Additional, modified, or non-generic / differentiated LCIA methods As already mentioned in chapter 6.7, in case the inventory work reveals the need to address additional impacts that where not originally considered, the respective scope step has to be revised. In summary: If a characterisation factor is missing for an elementary flow in the inventory, which is known to contribute to an impact category, its potential importance should be checked. If the contribution from the elementary flow is found to be potentially significant, an attempt should be made to estimate the missing characterisation factor, and if this is not possible, the fact of a potentially relevant missing characterisation factor must be reported, and the potential influence of the missing factor must be considered in the interpretation of the results


Normalisation and weighting necessary? The decision of inclusion/exclusion of normalisation and weighting shall have been made and documented in the initial scope definition (see chapter 6.7.7). Note that normalisation and weighting may be required as interim step for defining the quantitative cut-off rules (see chapter 6.6.3) and for checking the achieved completeness of the inventory (see chapter 9.3.2); this depends on the chosen approach for implementing the cut-off rules. If used exclusively for this purpose, the respective normalised and weighted figures are not staying in the data set or report. In comparisons without normalisation and weighting, LCIA results of the different impact categories or damages/areas-of-protection may point to different directions, i.e. for different impact categories not always the alternative product performs best


for different impact categories not always the alternative product performs best. However, if the study is intended to support a comparative assertion to be disclosed to the public, no form of numerical, value-based weighting of the indicator results is permitted to be published in accordance with ISO 14040 and 14044:2006. For in-house purposes, the use of normalisation and weighting – preferably using several different approaches and value perspectives - can help to demonstrate the robustness of the analysis. If in contrast all impact indicators point into the same direction, the LCIA results can already be the basis for interpretation phase of the LCA, including for comparative studies, clearly identifying a superior alternative (or, in case of limited significance of the differences, identifying equality of the compared alternatives).


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results Provisions: 8.2 Calculation of LCIA results Note that this provision applies to all types of deliverables of the study, while for unit process, partly terminated system and LCI results data sets as deliverables only to quantify the achieved completeness and precision, as they needs to be evaluated from the system's perspective. Note: If third-party LCIA methods are used that correctly provide characterisation factors for all used elementary flows, the first two following provisions mean to exclusively control that this has been done correctly


For any newly created elementary flow however, the characterisation factor has to be assigned and/or developed (see also chapter 6.7.4): I) SHALL - Classification of elementary flows: All elementary flows of the inventory shall be assigned to those one or more impact categories to which they contribute (“classification”) and that were selected for the impact assessment in the scope definition of the study. II) SHALL - Characterisation of elementary flows: To all classified elementary flows each one quantitative characterisation factor shall be assigned for each category to which the flow relevantly contributes ("characterisation"). That factor expresses how much that flow contributes to the impact category indicator (at midpoint level) or category endpoint indicator (at endpoint level). For midpoint level indicators this relative factor typically relates to a reference flow (e.g. it may be expressed in "kg CO2equivalents" per kg elementary flow in case of Global Warming Potential)


For midpoint level indicators this relative factor typically relates to a reference flow (e.g. it may be expressed in "kg CO2equivalents" per kg elementary flow in case of Global Warming Potential). For endpoint level indicators it typically relates to a specific damage that relates to the broader area of protection. Examples are e.g. species loss measured e.g. as potentially displaced fraction of species for an affected area and duration (pdf*m2*a), or damage to Human health measured e.g. in Disability Adjusted Life Years (DALYs). (For terms and details refer to the separate document "Framework and requirements for Life Cycle Impact Assessment (LCIA) models and indicators"). III) SHALL - Calculate LCIA results per impact category: For each impact category separately, calculate the LCIA indicator results by multiplying191 the amount of each contributing (i.e. classified) elementary flow of the inventory with its characterisation factor


classified) elementary flow of the inventory with its characterisation factor. The results may be summed up per impact category, but summing up shall not be done across impact categories. Note that this is done with either the midpoint level (impact potential) or the endpoint level (damage) factors, as had to be decided in scope chapter 6.7.7. IV) SHALL - Separately calculate LCIA results of long-term emissions: LCIA results of long-term emissions (i.e. beyond 100 years from the time of the study) shall be calculated separately from the LCIA results that relate to interventions that occur within 100 years from the time of study. [ISO!] Note: Given the different extent of uncertainty, these two sets of results will later be presented separately while discussed jointly. V) SHALL - Separately calculate non-generic LCIA results, if included: In the case additional or modified, non-generic (e.g


V) SHALL - Separately calculate non-generic LCIA results, if included: In the case additional or modified, non-generic (e.g. geographically or otherwise differentiated) characterisation factors or LCIA methods are used, the results applying the original, generic LCIA methods shall be calculated (and later be presented and discussed) 191 Certain LCIA methods use non-linear relationships for the characterisation; if such are used the calculation is non-linear.


ILCD Handbook: General guide for Life Cycle Assessment - Detailed guidance First edition 8 Life Cycle Impact Assessment - calculating LCIA results separately as well. [ISO!] VI) SHOULD - Keep results of non-LCA impacts separate: For LCIA results of impacts that are outside the LCA frame93 but that were considered relevant for the analysed or compared system(s) and have been included quantitatively, the inventory, impact assessment, etc. shall be kept separately for clear interpretation. [ISO+] Note that classification and characterisation of all elementary flows is typically already done in combined LCI / LCIA database packages or LCA software. In any case this is to be checked responsibly by the LCA practitioner. The step of manual classification and assigning characterisation factors applies hence especially to newly created or imported elementary flows


The step of manual classification and assigning characterisation factors applies hence especially to newly created or imported elementary flows. It is one of the most widely found errors to not classify and characterise newly introduced flows despite of their environmental relevance. The "frequent errors" box in the main text of this chapter provides some guidance for identifying and solving such cases. 8.3 Normalisation192 (Refers to ISO 14044:2006 chapter 4.4.3.2) Introduction and overview Normalisation is an optional step under ISO 14044:2006. It supports the interpretation of the impact profile and is the first step193 towards a fully aggregated result that additionally requires a weighting across indicators (see next chapter). Normalised LCIA results give for each impact topic on midpoint level (e.g. Climate change, Eutrophication, etc.) or area of protection on endpoint level (e.g


Normalised LCIA results give for each impact topic on midpoint level (e.g. Climate change, Eutrophication, etc.) or area of protection on endpoint level (e.g. Human health, Natural environment, Natural resources) the relative share of the impact of the analysed system in the total impact of this category per average citizen or globally, per country, etc. When displaying the normalised LCIA results of the different impact topics next to each other, it can hence be seen to which impact topics the analysed system contributes relatively more and to which less. Also to implement the cut-off criteria, weighted and normalised LCIA results can be used (see chapter 6.6.3). If this approach has been chosen, normalisation is a required step for all kinds of deliverables of the LCI/LCA study


If this approach has been chosen, normalisation is a required step for all kinds of deliverables of the LCI/LCA study. The decision about inclusion of normalisation and the used normalisation basis has been made and documented in the first scope definition; it is binding and shall not be changed later during the study (see chapter 6.7.6). Calculating normalised LCIA results Normalised LCIA results are obtained by dividing the LCIA results by the normalisation basis, separately for each impact category (for midpoint level related approaches) or area of protection (for endpoint level related approaches). No comparison across impact topics The different impact topics on midpoint level are typically understood to be of different absolute relevance (e.g. the issue Climate change may be judged to be more important than 192 "Grouping" is not addressed in this guidance document as not seen as adding practical value in context of decision support


the issue Climate change may be judged to be more important than 192 "Grouping" is not addressed in this guidance document as not seen as adding practical value in context of decision support. If it is planned to include a grouping step in an LCA study, please refer to the ISO 14044 provisions. 193 Note that there are also weighting approaches that do not include an initial normalisation step. Note furthermore that also for endpoint / damage modelling a weighting is required (across the areas-of-protection) if a single indicator is aimed at.