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G-13 (Buildings) / G-12 (Products) Infrastructure machinery and capital equipment for material production, energy, water, waste and transport for screening and simplified LCA

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Aspect G-13 (Buildings) / G-12 (Products) Infrastructure machinery and capital equipment for material production, energy, water, waste and transport for screening and simplified LCA
Description
 Different LCA databases and datasets with different boundaries are available. These databases apply different rules for including or excluding infrastructure in LCA datasets (e.g. owing to database policy or cut-off-rules). Infrastructure, especially related to processes that have a high impact for other datasets (e.g. the production of electricity), can have an environmental impact that should not necessarily be neglected using cut-off rules. The infrastructure covered here comprises not only the capital equipment and machinery (the factories, equipment and machines) that are used to extract and process materials and manufacture products, but also the infrastructure for energy, water, waste and transport processes. Current practices show that the datasets from the various databases do not have the same system boundaries; sometimes infrastructure is included, and sometimes it is excluded.When and how should infrastructure, etc. related to material production capital goods, energy production, waste and transportation be excluded or included?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions The inclusion or exclusion of infrastructure is especially relevant for background data. In general, infrastructure, machinery and capital equipment should not be excluded systematically, but cut-off criteria should be considered depending on the impact categories.In common LCA practice, the LCA practitioner does not have an influence on the database modelling, or on the decision whether or not to include infrastructure in datasets. As a result, this depends directly on which background data to use. Hence, no provision is given on the subject of the general inclusion or exclusion of infrastructure etc. as, owing to restricted data availability, practitioners typically are not free to decide this matter in terms of databases or consistent datasets. For the inclusion or exclusion of infrastructure in the foreground system, the following provisions should be applied:For screening and simplified LCA, capital equipment and machinery may be omitted, owing to the application of provisions from EN 15804 and the corresponding cut-off rules. Examples for cases where these points are important are mentioned in the guidance section below.
Rules from:

EN 15978

 

 7.4.3 Boundaries of the construction process stage (Modules A4 – A5)7.4.3.1 General

7.4.3.2 Boundary of the transport to and from site (Module A4)

ILCD

 6.6.2 Qualitative definition of system boundaries
Systematic exclusion of activity types. ILCD states that “a systematic exclusion of e.g. transport, infrastructures, services, administration activities, etc. is not appropriate unless necessary according to the specific goal of the LCI/LCA study (e.g. if the quantitative relevance of such activity types is to be analysed, the system would be modeled twice, once with and once without them).”
Guidance
 The infrastructure, machinery and capital goods covered here are the capital equipment and machinery (the factories, equipment and machines) that are used to extract and process materials and manufacture products, and also the infrastructure for energy, water, waste and transport processes.According to the ILCD Handbook, a systematic exclusion of e.g. transport, infrastructure, services, administration activities, etc. is not appropriate unless necessary according to the specific goal of the LCI/LCA study. In principle, all quantitatively relevant activities that can be attributed to a system should be included in the system boundaries unless they are quantitatively irrelevant, applying the cut-off criteria.If the practitioner is in the position to (or needs to) collect foreground data on the production of materials or the treatment of waste, then the principle of focusing on the collection of important data (in terms of LCA results) should prevail. To this end, the predefined cut-off rules should be applied.In common LCA practice, however, background datasets are typically accepted as they are. To improve the consistency of a study, it is strongly advised that data from methodologically consistent databases be used. This then means that the consideration of infrastructure is generally consistent within the database. However, the practitioner should check, depending on the goal and scope of the study, whether  the treatment of infrastructure processes in the background data is relevant.Guidance related to cut-off rules should be used for infrastructure as part of the foreground model (i.e. the infrastructure that is directly included by the practitioner). The relevance of processes and inputs depends on the impact categories assessed. As a consequence, the inclusion or exclusion of infrastructure, etc. has to be evaluated with care.From an energy or global warming point of view, it may be possible to leave out the infrastructure related to the production of materials, as previous studies have shown that it represents less than 5% of the impact [Frischknecht 2007]. In other cases, capital equipment and machinery are important, e.g. wind power or water power.The normal assumption is that capital equipment and machinery for a manufacturing process are not significant, and are not considered in LCA. They may potentially be relevant if production output is very small, or the capital equipment has a very short lifespan, or the product has an extremely low impact. This could be reviewed initially by considering the importance of the annualized capital costs relative to the production costs, bearing in mind that environmental impacts are not discounted over time in the way financial costs are. If considered potentially important, the likely service life (length of useful service) for buildings, equipment and machinery would need to be reviewed so that the amount of materials used per annum of production could be considered, and compared with the cut-off criterion of 1% of total mass of inputs for the same period.For renewable energy generation as an energy process, e.g. energy from wind turbines or photovoltaic (PV) cells, the main impact is purely capital equipment, i.e. the manufacture of the turbine and infrastructure or the PV cells. In these instances, the energy processes should include capital equipment.In general it would be good practice to provide information in the background report on the inclusion or exclusion of infrastructure within any secondary datasets used, and its significance if included.

This aspect may need to be revised in a future version of the EeBGuide if additional impact categories such as land use or human toxicity and ecotoxicity are assessed (as mandatory indicators).

G-14 (Buildings) / G-13 (Products) Infrastructure machinery and capital equipment for material production, energy, water, waste and transport for complete LCA.

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Aspect G-14 (Buildings) / G-13 (Products) Infrastructure machinery and capital equipment for material production, energy, water, waste and transport for complete LCA.
Description
 Various LCA databases and datasets with different boundaries are available. These databases apply different rules on the inclusion or exclusion of infrastructure in LCA datasets (e.g. owing to database policy or cut-off-rules). Infrastructure, especially related to processes that have a high impact for other datasets (e.g. the production of electricity), can have an environmental impact that should not necessarily be neglected because of cut-off rules. The infrastructure covered here comprises not only the capital equipment and machinery (the factories, equipment and machines) that are used to extract and process materials and manufacture products, but also the infrastructure for energy, water, waste and transport processes. Current practices show that the datasets from different databases do not have the same system boundaries; sometimes infrastructure is included, and sometimes it is excluded.When and how should infrastructure, etc. related to material production, capital goods, energy production, waste and transportation be excluded or included?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions The inclusion or exclusion of infrastructure is especially relevant for background data. In general, infrastructure, machinery and capital equipment should not be systematically excluded, but cut-off criteria should be considered, depending on the impact categories.In common LCA practice, the LCA practitioner does not have an influence on the database modelling, or on the decision whether to include infrastructure in datasets or not. As a consequence, this matter depends directly on the decision as to which background data are used. Hence no provision is given on the subject of the general inclusion or exclusion of infrastructure etc. as, owing to restricted data availability, practitioners typically are not free to decide on this matter in terms of databases or consistent datasets. It would be good practice to provide information in the background report on the inclusion or exclusion of infrastructure within any secondary datasets used, and on its significance, if included.For the inclusion or exclusion of infrastructures in the foreground system, the following provisions should be applied.For complete LCA, infrastructure, capital equipment and machinery should be included, unless the application of cut-off rules leads to the omission of these elements.
Rules from:

EN 15978

 7.4.3 Boundaries of the construction process stage (Modules A4, A5)
7.4.3.1 General
7.4.3.2 Boundary of the Transport to and from site (Module A4)

ILCD

 6.6.2 Qualitative definition of system boundaries
Systematic exclusion of activity types. ILCD states that “a systematic exclusion of e.g. transport, infrastructures, services, administration activities, etc. is not appropriate unless necessary according to the specific goal of the LCI/LCA study (e.g. if the quantitative relevance of such activity types is to be analysed, the system would be modelled twice, once with and once without them).”
Guidance
 The infrastructure, machinery and capital goods covered here are not only the capital equipment and machinery (the factories, equipment and machines) that are used to extract and process materials and manufacture products, but also the infrastructure for energy, water, waste and transport processes.According to the ILCD Handbook, a systematic exclusion of e.g. transport, infrastructure, services, administration activities etc. is not appropriate, unless necessary according to the specific goal of the LCI/LCA study. In principle, all quantitatively relevant activities that can be attributed to a system should be included in the system boundaries unless they are quantitatively irrelevant, applying the cut-off criteria.If the practitioner is in the position to (or needs to) collect foreground data on the production of materials or the treatment of waste, then the principle of focusing on the collection of important data (in terms of LCA results) should prevail. To this end, the predefined cut-off rules should be applied.In common LCA practice, however, background datasets are typically accepted as they are. To improve the consistency of a study, it is strongly advised that data from methodologically consistent databases be used, particularly as this subject is not addressed consistently across database borders. To use one consistent database, then, means that the consideration of infrastructure is generally consistent within the study. EPDs from different EPD programmes may be inconsistent in this context, and consistency between generic background databases and EPDs is not generally assured. It can be expected, however, that both EPD programmes and generic databases will yield documentation on this matter.In practical applications, however, the practitioner may find it impossible to conduct a study with truly consistent data. Here, a decision has to be made between consistency in the consideration of infrastructure and the accuracy of available datasets, and for typical LCA use in the construction sector the accuracy of datasets may prevail.Guidance related to cut-off rules should be used for infrastructure as part of the foreground model (i.e. infrastructure that is directly included by the practitioner). The relevance of processes and inputs depends on the impact categories assessed. As a consequence, the inclusion or exclusion of infrastructure etc. has to be evaluated with care.From an energy or global warming point of view, it may be possible to leave out infrastructure related to the production of materials, as previous studies have shown that this typically represents less than 5% of the total impact [Frischknecht 2007]. In other cases, capital equipment and machinery are important, e.g. wind power or water power.The normal assumption is that capital equipment and machinery for a manufacturing process are not significant, and are not considered in LCA. They may potentially be relevant if production output is very small, if the capital equipment has a very short lifespan, or if the product has an extremely low impact. This could initially be reviewed by considering the importance of the annual capital costs relative to the production costs, bearing in mind that environmental impacts are not discounted over time in the financial costs are. If considered potentially important, the likely service life (length of useful service) for buildings, equipment and machinery would need to be reviewed, so that the amount of materials used per annum of production can be considered and compared with the cut-off criterion of 1% of total mass of inputs for the same period.For renewable energy generation as an energy process, e.g. energy from wind turbines or photovoltaic (PV) cells, the main impact is purely capital equipment, i.e. the manufacture of the turbine and infrastructure or the PV cells. In these instances, the energy processes should include capital equipment.

In general it would be good practice to provide information in the background report on the inclusion or exclusion of infrastructure within any secondary datasets used, and on its potential significance.

This aspect may have to be revised in the future if additional impact categories such as land use or human toxicity and ecotoxicity are generally available and addressed in this guidance.

G-15 (Buildings) / G-14 (Products) Transport of goods in LCA studies

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Aspect G-15 (Buildings) / G-14 (Products) Transport of goods in LCA studies
Description
 With globalized supply chains, logistic processes occur throughout the life cycle of every product. The most important ones are transport processes, where several possibilities exist for the activity of carrying goods (e.g. by truck, ship or airplane) for the various life cycle stages, e.g. raw materials supply, manufacturing, on-site implementation, end of life. The environmental impacts connected with transport processes depend on several factors, e.g. the transport distance, the load factor or the empty return.How should the transport of goods be considered?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions Generally speaking, in all LCA studies of a product or a building, transportation processes should be included for every life cycle stage: raw materials supply, manufacturing, transportation to the site, use, and end of life.The EeBGuide provisions are adapted depending on the study types and the corresponding life cycle stages. For screening and simplified LCA studies, transport to the building site and transport to end-of-life facilities are optional, owing to their potentially minor relevance, whereas they should be included for complete LCA. If they are included, the results should be documented separately.The provisions for a specific life cycle stage (e.g. Module A4) supersede the general provision provided here. The practitioner should refer to the provisions for the corresponding aspects: ‘Transport of raw materials to the manufacturer’, ‘Transport of products to the construction site – screening and simplified LCA’, ‘Transport of products to the construction site – complete LCA’, ‘Transport of wastes to landfill, incineration and recycling facilities’.
Other kinds of transport of goods not directly related to a building product may be taken into account for building LCA studies if they are relevant for the goal and scope of the study. If they are included, included, the practitioner should refer to the provisions for the corresponding aspects: ‘Transport of construction machinery to the building site – screening and simplified LCA’,
‘Transport of construction machinery to the building site – complete LCA’.
Rules  from:

EN 15978

 In EN 15978, the conventional life cycle stages take into account the related transportation processes that occur during the production, construction, use and end-of-life phases.
7.4.3.2 Boundary of the transport to and from site (Module A4)
7.4.3.3 Boundary of the construction installation process (Module A5)
7.4.4 Boundaries of the use stage (Modules B1–B7)
7.4.5 Boundary of the end-of-life stage (Modules C1–C4)
7.4.6 Boundary for the benefits and loads beyond the system boundary (Module D)

=> Transport of goods, wastes, construction equipment and construction materials should be included in the different life cycle stages

EN 15804

 In EN 15804, the conventional life cycle stages take into account the related transportation processes that occur during the production, construction, use and end-of-life phases.
6.3.4.2 Product stage
6.3.4.3 Construction stage
7.3.2.1 A4, Transport to the building site
7.3.2.2 A5, Installation in the building
7.3.4 End-of-life

=> Transport of goods, wastes, construction equipment and construction materials should be included in the different life cycle stages
Guidance
 Any life cycle stages (i.e. Modules A1–A3, A4, A5, B and C) should include the related transport processes. The practitioner should be aware that even if a life cycle stage is labelled e.g. A3 ‘Manufacturing’, internal transport of goods can occur. Thus the transport-related impacts theoretically occur for each life cycle stage. For any gate-to-grave information module, additional information to support the generation of LCA data at the building level can be provided by means of a scenario. Module A4 includes only transport from the factory to the construction site. Earlier transport journeys are included in Modules A1 and A2. For example, in an EPD for a steel cladding panel, the transport of iron ore to the steelworks is included, with the extraction of iron ore, and the production of steel sheet via the blast furnace and basic oxygen furnace, in Module A1.  The transport of the steel sheet to the panel manufacturer is included in Module A2, panel manufacture is included in Module A3, and transport from the panel manufacturer to the construction site in Module A4.Transport is generally a significant impact only for materials with very low manufacturing impact, such as aggregates and timber. Also, transport by water has much lower impact than transport by road. Guidance mentioned in the cut-off rules aspect should be adopted for the inclusion of transport processes in the life cycle of a building or a product.Default values for average distances, truck types and load factors should reflect the actual transport. For average LCA data, the use of average values may be sufficiently accurate. Average values can be found in various literature sources e.g. in some transport reports available for each country, or in the documentation of transport LCA datasets from individual databases (e.g. ecoinvent, ELCD, GaBi). Further guidance adapted to the study type and to the life cycle stage is given in the other aspects.

G-16 (Buildings) / G-15 (Products) Accounting for carbon storage/carbon sequestration

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Aspect G-16 (Buildings) / G-15 (Products) Accounting for carbon storage/carbon sequestration
Description
 Some products (e.g. wooden products) take up atmospheric carbon dioxide while producing biomass. Concrete- and lime-based products can also take up atmospheric carbon dioxide through recarbonization during the use phase . By using these materials or products, this fixed CO2 is stored during the service life of the product. It is then released during combustion processes, or in landfill during full or partial decay of the biomass, as either CO2 or methane, which itself may be captured to produce CO2. Owing to the storage of carbon of biogenic origin in some products during the use of these materials, the CO2 stored is not released in today’s ecosphere but at some future date. Usually, 100-year assessment periods for the fate of greenhouse gases are taken into account in LCA studies (use of the indicator global warming potential, GWP100), but, depending on the case, this period can be insufficient to counteract the storage period.In this case, how should the biogenic carbon be taken into account? Should this temporary storage effect be accounted for? Also, the matter of sequestration of carbon in soils and organic matter due to land-use changes is frequently discussed. How should this aspect be treated?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings building products screening LCA simplified LCA complete LCA
Provisions As a conservative approach, the storage or sequestration of biogenic carbon as an additional benefit should not be accounted for, as this is a temporary effect. All greenhouse-gas-related environmental impacts should be quantified solely with the use of IPCC’s GWP-100 impact category. This means that the uptake of carbon dioxide into biomass is considered in the inputs to biomass production, and the emissions of biogenic carbon (as carbon dioxide or methane) are considered in the outputs.
Rules from

ILCD

 

 Provisions 7.4.3.7 Future processes and elementary flows
Citation from provisions 7.4.3.7:
“VII) SHALL – Inventory temporary carbon storage and delayed GHG emissions: only if temporary carbon storage in bio-based goods is considered […] delayed emission as CO2 or CH4 shall be modelled analogously to delayed emissions of fossil carbon dioxide and other greenhouse gases” Additional citation from the ILCD Handbook:The uptake of “carbon dioxide” by plants shall be inventoried under “resources from air”. This applies to all photosynthetic organisms.

The ILCD Handbook recommends that for better methodological clarity and flexibility, as well as easier communication, the release of carbon dioxide and methane be additionally differentiated between fossil and biological sources. Both the uptake of carbon dioxide from the atmosphere and the release of both fossil and biogenic carbon dioxide are assigned characterization factors for the impact assessment. The full provision for inventory of temporary carbon storage and delayed GHG emissions can be found in the ILCD Handbook.
Guidance
 This aspect is under intense discussion within various organizations. Different perceptions exist, and various documents propose different solutions to this question. For example, some documents define ‘discounts’ for the temporal storage of carbon in products. Others suggest, for example, reduction factors to be applied to GWP results for a temporal sequestration of carbon in soil and organic matter due to land-use change.In order to be flexible concerning future development of and consensus-building on this aspect, it is helpful to track carbon with a distinction made between biogenic and fossil sources. For example, in the background LCI databases, it is likely that elementary flows will be found such as:Resources: ‘carbon dioxide (resource), in air’Air emissions: ‘carbon dioxide (fossil), in air’ and‘carbon dioxide (biogenic), in air’.This is also valid for methane and carbon monoxide.Further information can be found in the following sources:

  • ISO working group on carbon footprint;
  • PAS 2050.
  • Standard in preparation in CEN TC 175 prEN 16449: ‘Wood and wood-based products – Calculation of sequestration of atmospheric carbon dioxide’ (status: under approval)

The treatment of biomass at the end of life is covered in the aspects of Module C and this should be considered alongside this guidance.

G-17 Differences in background data system boundaries

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Aspect G-17 Differences in background data system boundaries
Description
 Currently, practitioners have to deal with various different data sources, such as public or commercial LCI databases, EPDs, literature, etc. All these data have been calculated by applying different rules, and so special attention has to be paid to assessing the consistency of these different sources. An increasing number of EPDs for building products are freely available in the market. These EPDs have been produced in the framework of different programmes, applying different product category rules (PCR) and system boundaries, and so they should not be directly compared nor combined. Recently, the EN 15804 standard has been approved, and in the coming years will foster harmonization between the various EPD programmes. In the meantime, how can the practitioner deal with differing background data?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions An increasing number of EPDs for building products are available. These EPDs apply different system boundaries, e.g. cradle to gate (product stage), cradle to grave (the whole life cycle) and cradle to gate with options (Modules A1–A3 plus other, additional modules). If the EPD is EN 15804 compliant, then the information is declared separately for each module, facilitating its use in building LCA studies. EPDs that comply with EN 15804 should also provide additional technical information to ensure proper understanding of a product’s function in a building by supporting scenario development at the building level.For all these reasons, EN 15804-compliant EPDs can be accepted as a data source for building LCA as well as generic data (if the goal is to do e.g. a screening LCA). These EPD data may also be seen as an appropriate data source for background data as well as the usual generic data.
Rules from:
 EN 15804
5.2 Types of EPD with respect to life cycle stages coveredEN 15978
10 Selection of environmental data and other information – Use of Environmental Product Declaration(s)
Guidance
 Different EPDs and other background data may be used for a building LCA study; however, special care has to be taken when using these different data sources for building LCA. In this sense, it is key to have a good understanding of whether the LCA-based information found in an EPD represents the product stage only (e.g. cradle to gate), the product stage and selected further life cycle stages (cradle to gate with options EPD) or the complete life cycle of the product (cradle to grave). Additional technical information included in the product’s EPD (such as service life, transportation distance, loss of the product on-site, etc.) would also be very useful for the assessment at the building level. In any case, consistency of the LCA modelling should be ensured so that the system boundary of the EPDs is homogeneous.Whenever possible, the use of EPDs that comply with EN 15804 should prevail, if they are more relevant for use in a national context than any other background data. In addition, the practitioner should check that the LCA-based information found in such EPDs is compatible with the scope of the study.In addition to such EN 15804-compliant EPDs, the practitioner most likely has to rely on various background data sources, such as public or commercial databases. It is strongly recommended that practitioners use as much data as possible from a consistent source (e.g. one public national database), which ideally should be methodologically consistent with the appropriate EPDs (e.g. from one national EPD programme with the same methodological assumptions). If EPD data are to be used as background data, it is important to ensure that they can be reused for further EPD – e.g. a raw material EPD used for a product EPD. In this context, it is important to have a data-compatible exchange format to ease the use of EPD (the information to be reused is likely to be only the cumulative impact results, as no LCI is provided in most EPD programmes).

G- 18 Allocation case for cement-based materials

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Aspect G- 18 Allocation case for cement-based materials
Description
 Increasing numbers of building products are being made of secondary raw materials (SRM), or of generated waste that can be recycled throughout their life cycle. On the one hand, recycling eliminates the need to use virgin raw materials. On the other hand, the new commercial interest in waste can be seen as a shift in their status from waste to co-product.Several industries use a considerable amount of waste produced in other economic sectors (e.g. the cement industry uses blast furnace slag from the steel industry, and fly ash from electricity production). Depending on the ‘end of waste‘ status of each product, allocation rules may be needed to separate the burdens between the producer of the waste and the user. The environmental impact of very common building materials can thus vary greatly, depending on the allocation rules chosen. How can this critical allocation case be treated, e.g. for the use of waste in the cement and concrete materials?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☐ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions The allocation rules should comply with EN 15804 and EN 15978. In addition, the rules of national EPD programmes should be followed (if available).
Rules from:

EN 15804

 6.4.3.2. Co-product allocation

ILCD

 14.4.1.2 Market value of waste/end-of-life product is above zero, i.e. it is a co-product14.4.1.3 Market value of waste/end-of-life product is negative
Guidance
 Generally speaking, the allocation rules should be defined in every national context, together with the relevant sectors that use and produce the waste or co-product).A manufacturer of building products using e.g. wastes from another economic sector needs to share burdens with the first user. The allocation actually depends on the ‘end-of-waste’ status: that is, whether the waste is treated as waste (treatment allocated to the first user, and reported in Module C) or whether it is treated as a new product (when end-of-waste status is reached, the waste is transformed into a product, and the processing is allocated to the new product life cycle).

One option is to look at the market value of the waste, as proposed in the ILCD Handbook (see reference above). For example, waste from the steel industry (blast furnace slag) or from electricity production (e.g. fly ash) may be used to produce cement with a low clinker content.

Current practice in Europe shows varying rules for the allocation of cement SRM. They are treated as co-products in the UK (and in the subsequent EPDs), whereas they are considered as waste in France and in Germany (and in the subsequent EPDs of these two countries). The new European Waste Directive (see below) is currently not being applied in a consistent way.

The practitioner, when using LCA data that may be sensitive to the allocation of by-products according to the EU Directive (considered either as waste or as co-product), should specify the allocation rules, especially for complete LCA. Sensitivity analysis should be conducted if the allocation of by-products has a significant role in the LCA results.

A third guidance point concerns the use of background data. Depending on the type of background data, they may not comply with the allocation rules. As the practitioner does not have an influence on the background data, the best recommendation is to be transparent, e.g. in the LCA methodological report.

Further information and references on this issue:

G-18 (Buildings) / G-16 (Products) Allocation

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Aspect G-18 (Buildings) / G-16 (Products) Allocation
Description
 Normally, LCA studies should focus only on a single product at a time. However, systems under assessment often produce more than one product. The same problem arises when different waste flows are treated collectively in the same process (e.g. incineration). In these situations, the allocation problem arises: that is, how to allocate the environmental loads of those shared processes to the products delivered. In the building sector, owing to its long supply chain and influence, virtually all allocation cases can be found, from raw materials supply and manufacture (e.g. co-production processes) to the end of life (e.g. energy recovery during the incineration of building products) but also during the use phase (e.g. allocation of renewable energy produced in the building) The allocation rules may have a significant influence on the LCA results, and so this is a key methodological aspect. How should allocation be tackled in the case of buildings and building products?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☒ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
existing buildings new buildings building products screening LCA simplified LCA complete LCA
Provisions According to ISO 14040/14044, the ILCD Handbook and the EN 15804/EN 15978 standards, when dealing with systems involving multiple products and recycling processes, allocation should be avoided as far as possible; when unavoidable, allocation should be considered carefully, and justified. Allocation should be handled as mentioned in EN 15804/EN 15978 and the ILCD Handbook. Other aspects provide guidance for the most frequently found allocation problems occurring for energy-efficient buildings or products.
Rules from:

EN 15804

 6.4.3 Allocation of input flows and output emissions
6.4.3.1 General
6.4.3.2 Co-product allocation
6.4.3.3 Allocation procedure of reuse, recycling and recovery

ILCD

 Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision

  • “I) SHALL – Analyse whether allocation can theoretically be avoided by substitution
  • II) SHALL – Aim at avoiding allocation by subdivision or virtual subdivision”

Provisions: 7.9.3 Solving multifunctionality by allocation

  • “I) SHALL – Share inventory between co-functions by allocation
  • II) SHALL – Differentiate multifunctional processes and multifunctional products
  • III) SHALL – Two-step procedure for multifunctional processes
    • III.a) First step and criterion “determining physical causality”
    • III.b) First step and criterion “determining physical causality”
    • III.c) Checklist for “determining physical causality” criteria
  • IV) SHOULD – Second step and criterion “market price”
  • V) SHOULD – Two-step procedure for multifunctional products
  • VI) SHALL – Attributional modelling of reuse, recycling, recovery
  • VII) SHALL – System-wide consistent application of allocation
  • VIII) SHALL – 100% rules”
Guidance

The following main allocation methods are frequently used in LCA practice:

  • allocation based on market price (e.g. a gold mine where other precious metals such as silver are also extracted as co-products);
  • allocation based on physical mass/volume/energy content;
  • allocation based on exergy (e.g. a refinery with a multitude of products with high energy value).

The mass allocation may be preferred, as it is less sensitive to market price changes. However, there are no globally uniform rules. For complete LCA, an in-depth analysis has to be made of this issue, and the allocation procedure applied has to be justified. This is also the case for a study with a special focus on a certain aspect (e.g. recycling).

The ILCD Handbook (see rules above) provides a comprehensive procedure for doing the allocation in a consistent way. The practitioner should make sure that allocation rules are applied in a consistent way throughout the assessed system.

For building LCA applications, this means that the data used for the study should have been modelled using the same allocation rules. For example, if the blast furnace slag is considered as a co-product when it leaves the system boundary of a construction steel product, then the cement should use the slag as a co-product linked to the fabrication of slag in the steel industry. The same rules apply if the slag is not allocated as co-products; then the cement should use it as a waste. If the allocation rules differ between the steel and the cement then the system is not balanced, which does not comply with the ILCD rules. Further information on this relevant example for the construction sector can be found in the corresponding aspect.

The practitioner should also check that the sum of inventories allocated to all the co-products is equal to the inventory of the system before allocation was done [ILCD 2011a].

In addition, the LCA practitioner should prove that the chosen allocation rule does not change the overall conclusions and results of the study. This can be applied by scenario analysis (see the corresponding aspect), if allocation is used in foreground systems. Scenario analyses are most likely not feasible for assessing the impacts of the allocation rules used within background datasets.

G-19 Allocation case: production of renewable energy on-site

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Aspect G-19 Allocation case: production of renewable energy on-site
Description
  The production of on-site renewable energy can occur at different time of the day, month and year, and may or may not meet on-site needs. Renewable energy may be consumed on site, or may be exported to the electricity grid or to a heating network, for example, according to the instantaneous needs of the building.How should this on-site energy production be accounted for, and can the loads and benefits be allocated between the electricity grid and the building?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☒ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings construction products screening LCA simplified LCA complete LCA
Provisions
The amount of renewable energy produced with the help of on-site systems to supply operational energy for the use of the building should be accounted for as part of the LCI of the building being assessed, attributing the on-site production to the building life cycle.The allocation of exported energy follows the case studies of EN 15978, Annex B.
Rules from:
 EN 15978
7.4.4.7 Boundary for the operational energy use (Module B6)Annex B (informative) Exported energy – Case studies

ILCD
Provisions: 7.9.3 Solving multifunctionality by allocation
Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision
Guidance
 The method for the calculation of on-site renewable energy production should be consistent with [EN 15643-1]. Renewable energy produced by systems located on the building site and supplying energy demand for building uses should be considered (e.g. thermal solar panels, photovoltaic panels, wind turbines…). Other thermal energy gain from on-site renewable energy sources (solar gains through windows or solar walls) can be also accounted for complete LCA. Calculation method should be reported and justified.Boundary for energy production at operational stage should be consistent with boundary for product (A1–A3) and construction processes (A4–A5) modules:

  • If the energy produced by the on-site system is accounted for in Module B6, the production system should be accounted for in Modules A1–A5.
  • The accounting of renewable primary energy for the operational stage should be consistent with the accounting of renewable primary energy for materials, the amount of renewable primary energy is the measured output energy, not the amount of energy potentially available.

For on-site systems exporting energy outside the building boundary see the aspect described in Module B6: “Operational energy calculation – Allocation of energy production for on-site systems connected to grid”.

G-20 (Buildings) / G-17 (Products) Allocation case: reuse, recycling and recovery

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Aspect G-20 (Buildings) / G-17 (Products) Allocation case: reuse, recycling and recovery
Description
 When the lifespan of a product ends, it can be reused, recycled, or used for recovery in another product system. These recovery operations entail a benefit for the system that yielded them. How to allocate these benefits to the system under study, or to other product systems that will recover these materials, is still an open topic within the LCA community.What allocation method should be used for the reuse, recycling and recovery of construction waste?

related study objective

 ☒ stand-alone LCA ☒ comparative assertion

related study phase

 ☒ ☒ ☐ ☐ ☐
goal and scope definition inventory analysis (LCI) impact assessment (LCIA) interpretation reporting

relevant for
new buildings existing buildings building products screening LCA simplified LCA complete LCA
Provisions According to EN 15804, components for reuse and materials for recycling and energy recovery are considered as potential resources for future use. The reuse, recycling and recovery operations result in benefits, but also entail environmental loads. In the case of EPDs (products), the net environmental impacts (positive or negative) should be quantified separately in a so-called ‘Module D’. Calculation of Module D impacts should be based on average existing technology, current practice, and the net impacts of the recovery processes in comparison with the impacts of producing the substituted good (energy or primary raw material). EN 15804 provides guidelines for allocation with regard to reuse, recycling and recovery.EN 15978 refers to EN 15804 to deal with scenarios for reuse, recovery and recycling potentials outside the system boundary of the building under assessment, in order to describe the processes that lead to future substitution of resources.
Rules from:
 EN 15804
6.4.3 Allocation of input flows and output emissions
6.4.3.1 General
6.4.3.2 Co-product allocation
6.4.3.3 Allocation procedure of reuse, recycling and recoveryILCD
7.8 Modelling the system
Provisions: 7.9.2 Avoiding allocation by subdivision or virtual subdivision
Provisions: 7.9.3 Solving multifunctionality by allocation
“VI) SHALL – Attributional modelling of reuse, recycling, recovery
VI.a) Follow general rules for multifunctionality, observing specific aspects
VI.a.i) Dealing with waste and end-of-life products of negative market value that generate secondary goods
VI.a.ii) True joint process to be identified
VI.b) Provisions:
VI.b.i) Negative market value
VI.b.i) Market value equal or above zero”

14 ANNEX C: Modelling reuse, recycling, and energy recovery
Guidance
 Allocation can have significant effects on the results of an LCA study. Therefore the allocation method should be documented as transparently as possible, with reference, if possible, to the European standards or the ILCD Handbook. The aspect ‘Allocation example for wooden products’ provides further guidance. A recent article presenting the concept of Module D was presented at the 20120 Symposium on LCA and Construction. For deeper insight into this subject, the interested practitioner may refer to this article: [Leroy 2012].