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Tag: Related study objective: comparative assertion

G-09 Object of assessment with regard to energy-efficient build-ings

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Aspect G-09 Object of assessment with regard to energy-efficient buildings
Description
 Life cycle assessment is a flexible methodology that can be applied to all kinds of product or building. It is important to specify whether the LCA methodology has to be adapted in terms of system boundaries or cut-off rules when applying it to an energy-efficient 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 Life cycle assessment is a flexible methodology that can be applied to all kind of building, whatever their environmental performance (or energy efficiency). For this reason, the definition of the object of assessment does not need to explicitly define specific levels of energy efficiency.The current and forthcoming definitions of an energy-efficient building may, however, support an LCA approach (i.e. from cradle to grave), as opposed to a focused assessment that looks only at the environmental aspects linked to operational energy use.
Rules from:

EN 15978

 7. Specification of the object of assessment
Guidance
 The energy efficiency of buildings during their operational stage generally does not influence definition of the object of assessment, as for a building LCA this generally refers to the building’s entire life cycle. For this purpose, it is recommended that national definitions across Europe be referred to , such as the German ‘passive houses’ or French ‘low energy buildings’ (BBC) and ‘positive energy buildings’(BEPOS).The main information concerning the object of assessment should be considered in the functional equivalent; other, secondary information may be also reported regarding the scope of the study.

G-10 Definition of system boundaries for products

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Aspect G-10 Definition of system boundaries for products
Description
 The system boundaries of product LCA can be different, depending on the goal and scope of the study. If the goal is to create an EPD, then the practitioner is likely to follow the EN 15804 standards. But even for EPD, the system boundaries can vary, depending on the type of data: cradle to gate, cradle to gate with options, or cradle-to-grave. For LCA used in ecodesign, it may be relevant to include the recycling potentials of the products, thus extending the system boundary (a cradle-to-cradle approach) – that is, including Module D if the study complies with EN 15804. Generally speaking, the main issue for any product LCA is to define what to include, especially for the production stage.How can the system boundaries be defined for product LCA?

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 practitioner should refer to the ILCD Handbook, or otherwise EN 15804, depending on the goal and scope of his study.For LCA studies that are compliant with EN 15804, the practitioner should be aware that different system boundaries can be selected: cradle to gate, cradle to gate with options, or cradle to grave.

If the results are intended to be used for comparative assertions, then the rules used to define the system boundaries should follow the ILCD Handbook.
Rules from:

EN 15804

 6.3.4 System boundaries

ILCD

 Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness)“I) SHALL – Scope of LCA

II) SHALL – Processes within the system boundary

III) SHALL – Flows across the system boundary

IV) SHALL –System boundary diagram

V) SHALL – List of exclusions

VI) SHALL – part-system and system-system relationships

VII) SHALL – System-external off-setting

VIII) SHALL – Quantitative cut-off criteria”

 

Provisions: 7.2.3 Identifying processes in attributional modelling

“[…] I) SHALL – Identifying processes within the system boundary

         I.a) Start from central process

         I.b) Foreground system

         I.c) Background system

         I.d) Justify and document exclusion

II) SHALL – Initial processes description”

As an illustration for product LCA, the ILCD Handbook details the different life cycle stages to take into account and the different types of data. It has to be mentioned that the foreground data collection (based on e.g. measured data from company) takes place during the gate-to-gate stage (see below). For the other data (e.g. extraction processes), the data are likely to be based on background data.

Figure 11: Cradle-to-grave, cradle-to-gate and gate-to-gate datasets as parts of the complete life cycle
Guidance
 Different cases can be found in practice. For EPD data, rules from EN 15804 should be applied. These types of EPD system boundary can be found, depending on the goal and scope (e.g. for 1 kg of declared unit for cement, the system boundaries will be only up to the gate of the plant).For E2B EI research projects, product LCA studies may be conducted for the full life cycle. The practitioner is likely to collect foreground data for the gate-to-gate stage among the project partners (e.g. a company involved in the project that would like to assess its new product), whereas for upstream or downstream processes the use of generic data may be sufficient. This last recommendation is also in line with EN 15804.

G-10 Definition of system boundaries for new buildings

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Aspect G-10 Definition of system boundaries for new buildings
Description
 A clear definition of the system boundaries is needed for improved understanding and interpretation of the LCA results, as well as to enable them to be used for comparative assertions (e.g. choice of design alternatives) or stand-alone LCA (e.g. benchmarking purposes).How should this system boundary be defined for new buildings?

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 For a new building, the system boundary should include all stages of the life cycle. This includes all the upstream and downstream processes needed to establish and maintain the function(s) of the building, from the acquisition of raw materials to their disposal, or to the point where materials exit the system boundary, either during or at the end of the building life cycle.For the inclusion of specific contributors (e.g. transport of people, water consumption etc.), the definition of the system boundaries is directly linked to the goal and scope definition (see the corresponding aspects).EN 15978 gives clear rules for setting the system boundary of a building. These rules follow the ‘modularity principle’: that is, where processes influence the building’s environmental performance during its life cycle, they should be assigned to the module in the life cycle where they occur. The system boundary for new buildings should be defined according to EN 15978 and the different study types (screening, simplified or complete).
Rules from:

EN 15978

 7.4.2–7.4.6 boundaries“The system boundary determines the unit processes that are taken into account for the object of assessment.For a new building, the system boundary shall include the whole life cycle.”
Guidance
 The rules given in EN 15978 should be applied (see above). This covers the entire building life cycle as defined with regard to the study type used. The system boundaries include the entire building and its foundations, the building’s curtilage in the building’s site and connected exterior works. In addition, the study type’s definitions should be applied.

G-11 Definition of system boundaries for existing buildings

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Aspect G-11 Definition of system boundaries for existing buildings
Description
 A clear definition of the system boundaries is needed to understand and interpret the LCA results better, as well as to use them for comparative assertions (e.g. choice of design alternatives) or stand-alone LCA (e.g. for benchmarking purposes). How should this system boundary be defined in the case of existing buildings?

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 For an existing building, the system boundary should include all stages representing the remaining service life and the end-of-life stage of the building.EN 15978 gives clear rules for setting the system boundary of a building. These rules follow the ‘modularity principle’: that is, where processes influence the building’s environmental performance during its life cycle, they should be assigned to the module in the life cycle where they occur.
Rules from:

EN 15978

 7.4.2 Boundary of the product stage (Modules A1 to A3)
7.4.3 Boundaries of the construction process stage (Modules A4 and 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)
The assessment should concern the building and its site. For existing buildings, the main issues are the use stage (B2 to B7) and the end-of-life stage. The system boundary should also include the production and transportation of any component and ancillary products used for maintenance (including cleaning) and transportation of any wastage from maintenance processes and the end-of-life processes.
Guidance
 The rules given in EN 15978 should be applied (see above). The LCA of an existing building can address different goals: for example, to compare different refurbishment scenarios and the current state of the building, or to compare a refurbishment scenario with an operation of demolition/new construction.For an existing building, five possible goals may be considered:

  • Scenario 1: Comparison of a rehabilitation operation with an operation of demolition/new construction.
  • Scenario 2: Comparison of a rehabilitation operation with no rehabilitation.
  • Scenario 3: Comparison of a rehabilitation operation with a reference rehabilitation operation.
  • Scenario 4: Evaluation of the absolute performance of an existing building without modification until demolition.
  • Scenario 5: Evaluation of the absolute performance of a rehabilitation operation.

Thus four different types of operation may be identified:

  • rehabilitation;
  • reference rehabilitation;
  • complete demolition and new construction;
  • maintenance of an existing building (maintaining performance during a given period).

A rehabilitation operation consists of a deconstruction operation (removal of products to change) and a reconstruction operation (adding new products to replace discarded ones). Reference rehabilitation is a generic rehabilitation that implies the use of standard construction materials, designs and processes. It is to be used for comparison purpose with regard to a specific rehabilitation scenario.

Defining the boundaries of the study implies selecting the items or contributors to the environmental impacts relevant to each use. The following contributors should be considered:

  • new building products (those of a new construction after demolition, or those that replace products discarded during rehabilitation);
  • products discarded during the operation;
  • products not discarded during the operation;
  • energy consumption of the building before the operation;
  • energy consumption after the operation;
  • water consumption of the building before the operation;
  • water consumption after the operation;
  • demolition operations;
  • deconstruction operations (discarding of products to be replaced);
  • reconstruction operations (replacement of discarded products);
  • new construction operations.

G-12 (Buildings) / G-11 (Products) Cut-off rules for screening, simplified, complete LCA

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Aspect G-12 (Buildings) / G-11 (Products) Cut-off rules for screening, simplified, complete LCA
Description
 Cut-off rules enable LCA practitioners to conduct LCA without having to model 100% of the product system. According to the ILCD Handbook, the cut-off criteria refer to the omission of non-relevant life cycle stages, activity types, specific processes and products and elementary flows from the system model. Cut-off rules are quantified in relation to the percentage of environmental impacts that have been approximated to be excluded via the cut-off. The apparent paradox is that one must know the final result of the LCA to be able to know which processes, elementary flows etc. can be left out [ILCD, 2011a]. But, if one knew the 100% impacts of a product, then there would be no need for a cut-off. In practice, the total inventory is always unknown, but must be extrapolated from the measured or calculated data.What should the cut-off rules be for a product LCA or a building LCA?

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 In general, ILCD provisions should be followed for the cut-off rules.For product and building LCA studies complying with EN 15804 and EN 15978 goal and scope definition, the cut-off rules should be adopted.For product and building LCA studies that comply with EeBGuide predefined study types, the cut-off rules should be adopted. They are defined to allow for a simplification of LCA, and in particular to reduce the complexity of the study.For screening and simplified building LCA, the practitioner should refer to the list of building products and technical equipment to take into account. The others remain optional – to date – owing to potentially missing data. However, they may be included if default values exist for these building products or technical equipment at the European level.For complete LCA studies, cut-off rules should be applied primarily according to the ILCD Handbook, but if this is not achievable in practice,  they may be applied according to EN 15804/EN 15978 (in this case, the study type is not entirely a complete LCA).
Rules from:

EN 15978

 7.4.3 Criteria for the exclusion of inputs and outputs

EN 15804

 7.3.5 Criteria for the exclusion of inputs and outputsThe cut-off rules given in EN 15804/EN 15978: “All inputs and outputs to a (unit) process shall be included in the calculation, for which data are available. Data gaps may be filled by conservative assumptions with average or generic data. Any assumptions for such choices shall be documented; In case of insufficient input data or data gaps for a unit process, materials and processes can be omitted, if the process contributes with less than 1% of mass or renewable or non-renewable primary energy of the total, and all excluded materials and processes do not exceed 5% of total energy use and mass.”

ILCD

 6.6.3 Quantitative definition of system boundaries – the cut-off criteria
ILCD states: “The application of cut-off criteria has to consider two main aspects: the translation of the cut-off criteria into operational criteria during data collection of the individual unit-processes and – before that – the procedural issue of how to overcome an apparent paradox:The apparent paradox is that one must know the final result of the LCA (so one can show that the omission of a certain process is insignificant for the overall results) to be able to know which processes, elementary flows etc. can be left out. This paradox is solved through the iterative approach used when performing an LCA, as described in ILCD Chapter 4 and with more details on the inventory part in ILCD Figure 5: the initial settings are to be revisited once or several times and refined in view of the outcome of the subsequent LCI data collection, modelling (including of alternative scenarios), LCIA results calculation, and interpretation (especially contribution, sensitivity, completeness checks and uncertainty analysis). These iterative steps are to be repeated until the results meet the completeness, accuracy and precision requirements as needed for the intended applications of the LCI/LCA study.” Provisions: 6.6 Deriving system boundaries and cut-off criteria (completeness)“VIII – SHALL Quantitative cut-off criteria

VIII.a) Overall environmental impact

VIII.b) Identify the aimed-at cut-off”

ISO 14044

 4.2.3.3.3 Criteria for the exclusion of inputs and outputs
Guidance
 Cut-off rules should not be used to hide results. Therefore it is mandatory to provide verifications for excluded parts.The application of cut-off rules is always highly dependent on the specific circumstances and the product; no general approaches can be defined, but some PCR documents for EPD or labelling schemes define specific cut-off rules, or the extent of the materials and products that should be included. Information from these sources can be stated when the exclusion of materials and products is justified. If appropriate data are available, they should be included in the LCA. If not, then conservative assumptions should be made, and documented transparently. If no appropriate data are available at all, cut-off rules can be applied and the respective aspect can be left out, which should be documented transparently with very special care when comparing product systems (ISO 14044: 4.2.3.3.3).

1) Specific guidance for product LCA studies
Cut-off rules for building product LCA can be defined, e.g. for the exclusion of capital equipment of the production plant, or the exclusion of ancillary materials such as plastic packaging of a raw material in the upstream processes.Practitioners should refer to the existing common rules in the background LCI database for the cut-off rules that should be applied. Generally speaking, the background data should not be modified to comply with the cut-off rule of simplified approaches such as EN 15804. The cut-off rules are defined mainly to ease data collection and modelling for the foreground data. For specific applications such as EPD, generic background data may be pre-verified, i.e. the cut-off rules are compliant with the PCR/EPD programme, so that the practitioner does not need to be concerned with this issue.

Practical guidance on the cut-off rules can be found in dedicated PCR for building products and technical equipment. Generally speaking, simplified approaches such as EPD may have a 5% cut-off rule in mass or in energy for the corresponding life cycle stage. However, it is generally recommended that the available LCI of the raw materials be accounted for, if available, rather than systematically neglect them to comply exactly with the 5% cut-off. The cut-off rules linked to mass and energy are also limited if the scope of the study is to assess toxicity and ecotoxicity indicators. Some raw materials, such as paints, may have a low energy or mass input while having a high toxicity effect. In this case they should be taken into account in the LCI of the building product. In current PCRs (e.g. the French PCR NF P01-010 standard), these substances are identified – e.g. in France as very toxic (T+), toxic (T), noxious (Xn), or dangerous (N) – and should be included in the inventory if there is an LCI available; otherwise they should be included in the methodological report.

 

2) Specific guidance for the cut-off rules for complete LCA of buildings

There is a difference in terms of cut-off rules between product LCA and building LCA. For product LCA, the cut-off rules are generally defined in an existing PCR, e.g. EN 15804 (see the  ‘Rules from’ section), or in the database. For building LCA studies the practitioner is likely to use already calculated LCA or EPD data. These data have already a cut-off rule linked to the product LCA studies (see the guidance above). At the building level, there is an additional layer of cut-off rules, which correspond to the number of building products quantified to model the full building.

EN 15978 states that the total excluded materials and processes should not exceed 5% of total energy use and mass. However, the cut-off should be used differently between screening, simplified and complete LCAs. The mass of the building is driven mainly by the structural components which can lead some products such as floor coverings being neglected. However, these are likely to have higher environmental impacts than the structural components for some specific impact categories. Therefore the cut-off rules should be extended in complete LCA to account for ILCD provisions.

The provisions in EN 15978 are somewhere in between a simplified and a complete LCA for the cut-off rules aspect.

 

3) Specific guidance for the cut-off rules for screening and simplified LCA of buildings

For building LCA, it is important to ease the process of doing an LCA study, as it is a time-consuming task to account of possibly hundreds of building products.

In the EeBGuide, the cut-off rules for screening and simplified LCA are less strict than for complete LCA, as some building products or technical equipment may not have LCA or EPD data in some countries.

In the current version of the EeBGuide these may be neglected, owing to potentially missing data, although the general rule for simplification would be to conduct a complete LCA, and then see whether  it is relevant to neglect these items (see 2.4 Study types). In any case, the limitation of building products to include should always be justified by the practitioner.

As an alternative for optional building products, it is also recommended that default values be used for these optional building products, as far as possible (see 2.4 Study types), as there are likely to exist in Europe, even if they are not very representative of a specific product. This enables the cut-off rules to be limited, even for screening or simplified LCA (validation step), while easing the completion of the study by practitioners through the use of default values.

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).