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Tag: Study type: Screening LCA

G-23 Choice of LCI/LCIA datasets for screening LCA

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Aspect G-23 Choice of LCI/LCIA datasets for screening LCA
Description
  Different LCI/LCA data are needed to assess the environmental impacts of buildings. They make it possible to quantify the different impacts related to the building products and equipment, the construction site, the operational energy and water uses, and the deconstruction of the building. Depending on the study type (screening, simplified, complete), different types of data can be used in practice, depending on their availabilities at the European level but also in a national context (average, generic or specific LCI/LCIA data for the building materials, products and processes).How can this be addressed for screening 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 building products screening LCA simplified LCA complete LCA
Provisions The LCA practitioner or the user of dedicated building LCA tools should use adapted data for the description of the building components in screening LCA.They can either represent a major part of the building (e.g. statistical data, such as a specified level of kWh/m² for the interior walls), a full building component (e.g. 1 m2 concrete block wall insulated with wood wool), a building product (e.g. 1 m2 of rock wool) or a building material (1 m3of ready-mixed concrete), depending on the need of the practitioner and the stage of the building project. Provisions for the choice of data to use for screening LCA for the construction site, the operational energy and water uses, and the deconstruction activities are described in the corresponding aspects.
Generic LCA data for the building elements cited above should come from available European or national generic LCA databases where the building is built. It is possible to use average data (e.g. average EPD) if generic LCA are missing, or are less appropriate to the context of the study. Generic LCA data may represent (if possible and if relevant) the total consumption mix in Europe (if the study is used for European projects) or in every European country, or the production mix in Europe or in every European country, or the production mix of a neighbouring country using appropriate rules to adapt the generic data to the new context.
Rules from:
 EN 15978
9.4 Type of data for the assessment
The type of LCA data for the assessment referred in EN 15978 to CEN/TR 15941. The choice of the data will depend on several aspects, including the stage of the building project, the intended use/scope etc. According to EN 15978 the data (bill of quantities, building description of components, or the LCA data) may be given in different types: aggregated, specific, generic, or average. They describe different levels of specificity concerning the description of the building components as well as the representativeness of the LCA data.

ILCD

7.5 Developing generic LCI data

7.6. Selection of secondary LCI datasets

7.7 Averaging LCI data

According to the ILCD Handbook, a dataset is a generic dataset if “it has been developed using at least partly other information then those measured for the specific process. This other information can be stoichiometric or other calculation models, patents and other plans for processes or products, expert judgements etc. Generic process can aim at representing a specific process or system or an average situation.”

ILCD also states that “a generic data represents a typical variant of the process or the system, an average dataset represents the average situation for the process or the system, in both cases within a specified geographic region and time. The difference lies in how the dataset is modelled: in the first case the product and its life cycle is specified with typical (or representative) characteristics and the inventory is modelled accordingly. In the second case several products (or technology or production plants) are separately modelled and the inventories are subsequently averaged.”
Guidance

In practice the data for a screening LCA can be based on generic assumptions, as they are used only for obtaining a rough estimate of the environmental impacts of a product system. Three different practical recommendations can be given for the use of data on the building elements, the associated LCA data and the currently available generic LCA databases.

1) Practical guidance for the use of data describing the building elements

The data describing the part of the building can be estimated using either the statistical results of a comprehensive study of newly constructed buildings, or a sample of representative buildings.

The data describing the building components can correspond to generic typical components, using default values for the main included products (width, thickness etc.). It may be possible to parameterize the thickness of the key included products (e.g. insulation or structural products) for each study or use.

Other data include building products and materials LCA data. These ‘raw’ data usually serve when deriving data for building components or part of the building. Consistency should be ensured between the different levels of data (part of the building, components, products and materials).

2) Practical guidance for the use of generic LCA data for a European or national context

Examples of generic data on building products representing the ‘consumption mix’ can be found, for example, for the reinforcing steel sold on the French market in [Gomès 2012]. However, generally speaking, generic national data representing the ‘consumption mix’ in the various European countries may be missing. In this case, the use of existing generic LCA data (from neighbouring European countries) or industry-based data (from the national context) can be used as proxy data, using appropriate adaptation/contextualization rules. More guidelines on this topic can be found e.g. in [Hodkova 2012].

3) Practical availability of generic databases in Europe that can be used by the practitioner

The building practitioner may use existing European or national databases to collect generic LCA data to describe the building elements, products and materials, depending on the needs. Examples of such databases can be found e.g. on the LCA resources directory of the European Commission – Joint Research Centre, section Databases’.Generic databases (mainly at the global or European levels) include, for example, ELCD, ESUCO and ecoinvent.

Other generic databases developed in some European countries include, for example: the German Ökobau.dat, the Swiss Catalogue Construction/KBOB databases, the French DIOGEN generic LCA database for construction materials used in civil engineering applications, and the various generic databases that are included in LCA software for buildings.

G-22 Data selection for a product LCA

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Aspect G-22 Data selection for a product LCA
Description
 Various data sources exist for the calculation of product LCA data. They differ for example in terms of specificity, age, completeness and certainty. What data requirements apply for the production of product LCA 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 In general, specifications are given with regard to EPD: see 6.3.7 ‘Quality requirements’ in EN 15804. National EPD programmes that apply to the context of the LCA study may give more specific guidance.
Rules from:

EN 15978

 6.3.6 Selection of data
6.3.7 Data quality requirements

CEN/TR 15941

 Sustainability of construction works — Environmental product declarations — Methodology for selection and use of generic data

ILCD

  

ISO 14044

 4.2.3.6 Data quality requirements
Guidance
 Specific data are data relating to the specific process being studied.  Generic data are more general data – they may for example be an average from a trade association, a specific dataset that is used as a proxy for typical production, or a dataset developed from literature sources. Data quality considers the relevance and quality of the dataset relative to the process being considered, taking account of

a)    age of data;

b)   geography;

c)    technology;

d)    precision;

e)    completeness;

f)     representativeness;

g)    consistency;

h)    reproducibility;

i)     sources of the data;

j)     uncertainty.

For screening and simplified LCA, it can be appropriate to use lower data quality requirements: for example, a single database for upstream and downstream data may be used without considering further data quality or appropriateness of individual datasets. For complete LCA, it is necessary to consider and report on the data quality. In some circumstances, where a dataset is of particular relevance to a study, or where no suitable dataset is available, it may be necessary to collect data from upstream or downstream processes rather than use generic data. The scope of this data collection will depend on the detail required.

EPD programmes may require specific databases to be used for comparability purposes in terms of methodology until EN 15804 compliant data are widely available. Once EN 15804 compliant databases are available, there should be no differentiation between EN 15804 compliant datasets, other than the scope of the data used. It may be advisable to use the background database that is required from the EPD programme that lies within the context of the LCA study. This means that, for improved consistency, a product LCA study may/should be based on the national EPD programme’s background study.

ILCD already provides guidance on sources of generic data such as the ELCD and proprietary databases.

G-26 Use of building physical description data

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Aspect  G-26 Use of building physical description data
Description
 The type, the format, the level of detail and the quality of building-related data depend on the time of assessment (e.g. concept stage, basic design stage, detailed design stage, as built), on the objective of the study, and on the building’s stakeholders. Which kind of data should be used for a building LCA study?

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 The data for describing the main building elements should be taken from the building’s project documentation already available at the time of the assessment; otherwise use specific documentation included in the LCA software for buildings (if relevant). Different building-related data may be used in the documentation, depending on the objective of the study and the time of the assessment. For example, for screening LCA, an average description of a building could be sufficient, whereas for complete LCA a specific and detailed description of the building should be used wherever possible. Once the building-related data are quantified, they should be associated with suitable LCA or EPD data (see aspect ‘LCA datasets’).
Rules from:
 EN 15978

7.5.2 Description of the physical characteristics of the building
9.4 Type of data for the assessmentThe choice of the data in EN 15978 will depend on several aspects, including the stage of the building project, and the intended use or scope. According to EN 15978 the data (either the bill of quantities, a building description of components, or the LCA data) may be given in different types: aggregated, specific, generic or average. They describe different levels of specificity concerning the description of the building components as well as the representativeness of the LCA data.
Guidance
 The description of the quantities of the building products may vary significantly in terms of precision between the early design of a building project and the very late stages the project.Practitioners should always ensure that the building description is consistent between the various documents used, as the documents are all not produced at the same, time and building projects change over time. For example, it is essential to check whether the energy consumption results are based on assumptions regarding the mass of the building products, rather than the quantity take-off available in separate documentation.Generally, in early design, the level of description is low, as the design team does not know yet exactly what the specific description of the elements will be. For instance, the reinforced concrete in early design stages is described mainly in ml or m3, with a ratio for the reinforcing steel included in the concrete.However, during the detailed design, the level of description of the building elements is increased. At this stage, the building-related data may be more precise for some building elements (e.g. for the façades), whereas for others (e.g. the floor coverings), it may be only roughly taken into account until the actual building occupants are found.Common units that can be found in the building’s project documentation are: ml, m2, m3, unit etc. The practitioner should be aware of the potential differences in terms of the functional or declared units of LCA data available in LCA software for buildings and some of the units of the building-related-data (the quantity take-off). Wherever possible, the practitioner should use the most appropriate LCA data that correctly match the building-related data for the corresponding stage of the project.

G-27 (Buildings) / G-25 (Products) Choice of environmental indicators – screening and simplified LCA

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Aspect G-27 (Buildings) / G-25 (Products) Choice of environmental indicators – screening and simplified LCA
Description
 The choice of a set of environmental indicators should always try to avoid pollution transfer. Currently, a large number of indicators can be found in the LCA literature. They fall into different: selected LCI indicators, midpoint life cycle impact assessment (LCIA) indicators, and endpoint LCIA indicators. Selected LCI flows can be useful in track some flow quantities: e.g. the use of secondary energy throughout the product’s life cycle. These are not impact indicators directly, but they can be useful in the interpretation phase of any LCA study. Mid-point LCIA indicators (or potential indicators) make it possible to characterize different environmental problems, such as climate change, ozone depletion, photochemical ozone formation, acidification, eutrophication and resource depletion. End-point LCIA indicators refer to actual damage categories such as damage to resources, damage to human health, and damage to the ecosystem.What are the useful and necessary environmental indicators and impact categories to be reported for an energy-efficient product or building? Which indicators and which methodology should be chosen?

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 In general, the set of indicators should be as comprehensive as possible, to avoid burden shifting. The EeBGuide does not provide predefined provisions regarding the number and the type of indicators for each study type, as they depend on the goal, the scope and the context of the study.Required environmental indicators to use are given in the EN 15978 and EN 15804 standards (which are harmonized indicators between the product and the building level), and also in the ILCD Handbook if other indicators need to be included.For screening and simplified LCA studies the choice of indicators is not regulated or limited. Generally speaking, in screening and simplified LCA a reduced set of indicators may be selected, which means that not all the EN 15804 and EN 15978 indicators have to be considered. In addition, optional indicators taken from the ILCD Handbook may be used to provide a more consistent set of indicators (if relevant).
Rules from:
 EN 15978
11 Calculation of the environmental indicators

EN 15804
7.2.3 Parameters describing environmental impacts

ILCD
Provisions: 6.7 Preparing the basis for impact assessment

“[…] VI) MAY – LCIA methodologies: […] select complete set of single LCIA methods rather than selecting and combining individual LCIA methods”

Provisions: 7.4.3.8 Reminder flows

I) MAY – Use reminder flows to keep original information for specific purposes

II) SHALL – exclude reminder flows from impact assessment

III) SHALL – Clearly identify reminder flows in the flow name

8 Life Cycle Impact Assessment – calculating LCIA results

Provisions: 8.2 Calculation of LCIA results

ILCD Handbook – Part – Analysing of existing Environmental Impact Assessment methodologies for use in Life Cycle Assessment

4 Requirements for specific impact categories

“For some impact categories, many alternative methods have been selected. This can be seen as a sign that there is no clear consensus on how to model such a method. Clear examples are acidification, eutrophication, land use and resources.”
Guidance
 The operational guidance for the environmental indicators can be broken down into two main aspects: the calculation rules for environmental indicators (in both CEN TC 350 standards and in the ILCD Handbook) and the number of indicators to select, depending on the study type.

1) Calculation rules (i.e. characterization factors and associated impact assessment method) for each LCIA indicator in EN 15804/EN 15978
Various LCIA methods are currently available to calculate the LCIA indicators that are mentioned in the CEN TC 350 standards. Recently, the ILCD Handbook has release the report ‘Characterization factors of the ILCD – Recommended Life Cycle Impact Assessment Methods’. In this report, several methods are analysed, and one is then suggested as the recommended method for each impact category. In the EeBGuide, the ILCD-recommended methods are provided for information in Appendix B for the following LCIA indicators: GWP, ODP, AP, EP, POCP and ADP (both elements and fossils).However, deviations in units are currently found between EN 15804/EN 15978 and the ILCD-recommended methods for:– AP (acidification potential, unit kg SO2-equiv. vs. accumulated exceedance, unit mole H+ eq);– EP (eutrophication potential, unit: kg PO43--equiv. vs. accumulated exceedance, unit: mole Neq).

A new method is now suggested for POCP calculations based on [Van Zelm 2008]. Other LCIA methods have been used so far for POCP calculations: for example the CML 2002 approach based on [Derwent 1998]. As a result, care has to be taken, and the method used for LCIA indicators should be clearly stated. In LCA studies across Europe, CML methods are frequently used for midpoint indicators. Also, EPD programmes usually provide results at indicator level, as is done by some generic databases. Using such data reduces the choice of impact methods and also yields a number of indicators to choose from.

PS: Please note that the ADP guidance is given in a separate aspect.

Harmonization of the LCIA indicators is expected soon. The aspect will be revised once there are agreed methods between CEN and ILCD.

2) Calculation rules for each indicator describing resource use and additional information (wastes etc.) in EN 15804/EN 15978

According to the ILCD Handbook, these flows are called ‘reminder flows’ (see ILCD rules above). The practitioner and LCA tool developer may be aware that, so far, not all the resource use indicators can be easily determined. In fact, the background databases used in LCA studies do not provide this information in a consistent way (e.g. ‘use of non-renewable primary energy excluding primary energy resources used by a raw material’). Others are potentially more easily available (e.g. ‘use of secondary fuels’). As the practitioner cannot influence the background data, this problem ultimately needs to be solved by the data providers.

3) Calculation rules for optional indicators (taken from the ILCD Handbook)

Currently there is no agreement on a single calculation method for impact categories not covered in CEN TC 350 (but available in the ILCD Handbook), such as land use, toxicity or ecotoxicity. The type of LCIA modelling between midpoint indicators and endpoint indicators are is subject to discussion. Therefore the EeBGuide does not provide strict provisions on these aspects. Please consult the corresponding aspects for more detailed guidance on those aspects that are not mandatory in the EeBGuide.

4) Number of indicators to consider, depending on the study type.

To select a relevant set of indicators, the practitioner should also try to have indicators covering the three area of protection: resources, ecosystems and human health. The indicators of EN 15804/EN 15978 correspond to these area of protection, but do not include all the impact categories, as some are still being debated within the LCA community. Additional aspects (see ‘Biodiversity’, ‘Land use’, ‘Toxicity and ecotoxicity’ etc.) provide guidance for the practitioner who would like to use them.

For screening and simplified LCA it may be possible to conduct LCA studies using a single indicator under specific conditions. For example:

– if the decision-maker is not very familiar with the LCA approach, or focuses only on energy or greenhouse gas issues;

– if the full LCI data needed to calculate all the LCIA indicators are not available for some national context.

However, it is strongly recommended that more than one environmental indicator be used, to avoid e.g. shifting of burdens. To that end, a selection of indicators from the EN 15978/EN 15804 standards (and from the ILCD Handbook if relevant) is recommended for screening and simplified LCA.

The indicators considered in the SBA common metrics project may be considered for a screening or simplified LCA (if relevant for the goal and scope of the study): non-renewable primary energy, GWP, water consumption and waste.

G-29 (Buildings) / G-27 (Products) Abiotic resources depletion indicator

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Aspect G-29 (Buildings) / G-27 (Products) Abiotic resources depletion indicator
Description
 In LCA, different indicators can be used for assessing the use of resources. These can be based on a thermodynamic approach (use of energy or exergy indicators), on a mass flow approach (use of a total mass requirement indicator), on a surplus of energy that will be needed for future extractions (ecoindicator approach), or on a scarcity approach (use of the ADP indicator developed at CML Leiden). According to the ILCD Handbook, the CML method uses the abiotic depletion potential (ADP), given in kg of antimony equivalents, to be multiplied by the amount of a given resource extracted. For ADP, the annual production of the resource (the extraction rate) is divided by the reserves squared, and the result is divided by the same ratio for the reference resource, antimony [ILCD, 2011a]. The CEN TC 350 standards recommend using the ADP indicator, but different forms of APD can be used, depending on the type of reserve and the available extraction rates.Which indicator and assumptions should be applied in this guidance document?

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 Adopt the provision of the indicators and methodology mentioned in EN 15978 and EN 15804 (‘Depletion of abiotic resources-elements’ and ‘Depletion of abiotic resources-fossil fuels’). EN 15804 refers to CML (Institute of Environmental Sciences Faculty of Science University of Leiden, Netherlands) as the characterization factor for ADP (elements and fossil), and the characterization factors for ADP fossil fuels are based on net calorific values at the point of extraction of the fossil fuels.
Rules from:
 EN 15978:
12.5 List of indicators used for assessment and expression of results
11.1.2 Indicators describing environmental impacts
EN 15804:
6.5 Impact assessment
7.2.3 Parameters describing environmental impactsILCD:
8 Life cycle impact assessment – calculating LCIA results
Provisions: 8.2 Calculation of LCIA results
ILCD Handbook – Part – Analysing of existing environmental impact assessment methodologies for use in life cycle assessment

4.11 Resource depletion

 “For some impact categories, many alternative methods have been selected. This can be seen as a sign that there is no clear consensus on how to model such a method. Clear examples are acidification, eutrophication, land use and resources.”

ILCD Handbook: Recommendations for life cycle impact assessment in the European context

3.11. Resources depletion

3.11.7 Recommended default method for category 2

“The CML method is recommended in the ILCD framework since it captures scarcity by including extraction as well as reserves of a given resource. Characterization factors are given for metals, fossil fuels and, in the case of reserve base and economic reserves, mineral compounds [Oers 2002]. In addition, the method covers most of the substances/materials identified as critical by the European Commission’s Ad-hoc Working Group on defining critical raw materials (European Commission 2010).”

[Oers 2002] give characterization factors for economic reserves, reserve base, and ultimate reserves. The characterization factors given for the reserve base are recommended, as this reflects a longer time horizon and the possibility of improvement in mining technology, making feasible the exploitation of previously sub-economic deposits.
Guidance
 Practitioners should keep in mind that for the LCIA indicator ‘Abiotic depletion’ there is a methodology available that provides different assumptions regarding the estimate of reserves, i.e. ultimate, base or economic [Guinée 2001], [Oers 2002].So far, EN 15804 and EN 15978 do not specify which kinds of reserve should be considered for the ADP calculation. Over the past few years, most LCA or EPD data have reported the ADP (both fossil and elements) based on ultimate reserves according to [Guinée 2001]. Recently, the ILCD Handbook released the report ‘Recommendations for life cycle impact assessment in the European context’ (First edition, December 2010) [EC 2011]. In this guide, it recommended that the base reserve be used for the ADP calculation for all the elements (aluminium, copper, etc.). This guidance will be updated when EN 15804 and EN 15978 are revised.The ADP (fossil or elements) characterization factors based upon the CML 2002 method can be downloaded from: http://cml.leiden.edu/research/industrialecology/researchprojects/finished/new-dutch-lca-guide.html. In addition, another link provides the latest version of the characterization factors for the CML 2002 impact categories: http://cml.leiden.edu/software/data-cmlia.html.In the construction sector, such an indicator (ADP) may be adapted to take into account the local depletion of resources such as gravel. This is still a research topic but more information can be found in recent scientific papers, e.g. [Habert 2009]

G-30 (Buildings) / G-28 (Products) Land use indicator

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Aspect G-30 (Buildings) / G-28 (Products) Land use indicator
Description
 Land-use change is linked to human activities such as the exploitation of land for agricultural, industrial, residential, recreational, or other purposes. Currently, several LCIA methods exist, providing both midpoint and endpoint characterization factors. According to the ILCD Handbook, the midpoint characterization factor for land use, in the earliest stage of the cause–effect chain, is usually taken as the amount and quality deficit of land occupied or transformed. Some midpoint methods use indicators such as soil structure, soil pH or soil organic carbon. The endpoint characterization factor refers mostly to the quantity of species lost due to land use, or to the change in net primary production (NPP) of the land used [ILCD 2011a].Based on these different approaches, should a land-use indicator be included in the LCA of a product or a 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 building products screening LCA simplified LCA complete LCA
Provisions Land use should not be included as a mandatory indicator, as there is currently no agreed scientific method available (as also mentioned in the EN 15804 and EN 15978 standards). Yet, if the goal and scope of the study mention the use of an LCIA indicator for land use, then the indicator that is used for the assessment needs to be described and referenced.
Rules from:
 EN 15978:
11. Calculation of the environmental indicators
“Note: Indicators for which there is no scientifically agreed calculation method within the context of LCA e.g. human health, ecotoxicity, biodiversity, land use are not included”
ILCD:
8 Life CYCLE IMPACT ASSESSMENT – calculating LCIA results
Provisions: 8.2 Calculation of LCIA results
13 Annex B: Calculation of CO2 emissions from land transformation
ILCD Handbook: Analysing of existing environmental impact assessment methodologies for use in life cycle assessment
“For some impact categories, many alternative methods have been selected. This can be seen as a sign that there is no clear consensus on how to model such a method. Clear examples are acidification, eutrophication, land use and resources.”

ILCD Handbook: Recommendations for life cycle impact assessment in the European context

3.10 Land use

Existing methods for land use that can be used at the midpoint level include: [Baitz 2002] which was further developed by [Bos 2008], [Milà I Canals 2007], [De Schryver 2009] and [Beck 2010].
Guidance
 If land-use change is intended to be assessed, it is recommended that recent LCA literature be consulted to identify a feasible and appropriate indicator. Such literature may include:– the analysis of available existing LCIA methods for land use provided by the ILCD Handbook (report available online: http://lct.jrc.ec.europa.eu/pdf-directory/ILCD-Handbook-LCIA-Background-analysis-online-12March2010.pdf);– the results of the UNEP/SETAC working group on ‘Operational Characterization Factors for Land Use in Life Cycle Impact Assessment’ (LULCIA) [Beck 2010]– several publications in the International Journal of Life Cycle Assessment, such as a recent paper on the ‘Principles of inventory of land use on a global scale’ [Koellner 2012].This aspect will need to be revised when an approved method is available.

G-32 (Buildings) / G-30 (Products) Human toxicity and ecotoxicity indicators

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Aspect G-32 (Buildings) / G-30 (Products) Human toxicity and ecotoxicity indicators
Description
 LCIA methodologies usually include midpoint or endpoint indicators for three area of protection: resources, human health and ecosystem. For the two last areas of protection, different indicators are currently available to assess the ecotoxicity and toxicity effects related to a product or a building life cycle. They classify the multimedia fate of chemicals into ecological compartments such as air, water and soil. On the one hand, accounting for toxicity and ecotoxicity effects allows a more comprehensive assessment in terms of the completeness of the set of indicators. On the other hand, these two impact categories are subject to very high uncertainties. Several indicators have been developed by the LCA community, which can lead to different conclusions [Van Caneghem 2010].Should toxicity and ecotoxicity indicators be used in an LCA of 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 building products screening LCA simplified LCA complete LCA
Provisions Adopt provision of the indicators mentioned in the EN 15804 and EN 15978 standards. These do not include toxicity or ecotoxicity methods, because there is so far no scientifically agreed method available.Yet, if the goal and scope of the study mention the use of an LCIA indicator for toxicity and ecotoxicity, the indicator that is used for the assessment needs to be described.
Rules from:
 EN 15978:
11. Calculation of the environmental indicators“Note: Indicators for which there is no scientifically agreed calculation method within the context of LCA e.g. human health, ecotoxicity, biodiversity, land use are not included”

ILCD:
8 Life cycle impact assessment – calculating LCIA results
Provisions: 8.2 Calculation of LCIA results
ILCD Handbook: Recommendations for life cycle impact assessment in the European context

3.3. Human toxicity
Existing methods for human toxicity aspects that can be used at the midpoint and endpoint level include: USEtox [Rosenbaum 2008] ReCiPe [Huijbregts 2009], IMPACT2002+ [Jolliet 2003] TRACI [Bare 2003], EDIP [Potting 2005], CML 2002 [Huijbregts 2000] and MEEuP [Kemna 2005]

ILCD states that “The use of USEtox as multimedia model, combining chemical fate and exposure with toxicological data, is recommended for midpoint indicators” for human toxicity.

ILCD states that “For the endpoint characterization, it is proposed as an initial basis to apply the most recent values that are proposed by Huijbregts et al. (2005a) using disability adjusted life years (DALYs)”

3.3.5 Discussion on uncertainties and the importance of spatial-temporal differentiation

3.9 Ecotoxicity

Existing methods for ecotoxicity aspects that can be used at the midpoint level include three groups according to their fate modelling:

 1. Full multimedia fate modelling: USEtox [Rosenbaum 2008], ReCiPe [Huijbregts 2009], IMPACT2002+ [Jolliet 2003], TRACI [Bare 2003],

2. Partial fate modelling – Environmental key properties: EDIP

3. No fate modelling: Swiss Ecoscarcity [Frischknecht 2008] and MEEuP [Kemna 2005]

ILCD states that “USEtox is preferred as the recommended default method for the midpoint evaluation of freshwater ecotoxicity impacts. This is equally consistent with the model recommended for toxicity impacts for humans. It results from a consensus building effort amongst related modellers and, hence, the underlying principles reflect common and agreed recommendations from these experts.” ILCD states that “No available method is recommended to address marine and terrestrial ecotoxicity.”

Endpoint level for ecotoxicity includes: EPS2000 [Steen 1999], ReCiPe [Huijbregts 2009] and IMPACT 2002+ [Jolliet 2003].

3.9.4 Discussion on uncertainties and the importance of spatial differentiation
Guidance
 The LCA practitioner in the building sector should be aware of the existing and recommended LCIA methods for assessing toxicity and ecotoxicity aspects. Current uncertainties are substantial for these impact categories, although it is generally recognized that it is better to have one indicator than no indicator at all for an impact category.The LCA practitioner in the building sector should also be aware that current efforts are under way at the international level to harmonize the toxicity and ecotoxicity models: see e.g. the USE-oTox model.The latest developments in LCIA for human toxicity have included a new compartment ‘indoor air emissions’ in the USETox model (which is recommended for use by the ILCD). Accounting for indoor air emissions is increasingly relevant, as human beings spend most of their time inside buildings.Such new LCIA developments have to be connected to the EeBGuide aspect of Module B1 ‘Release of dangerous substances to air during the use stage’. The previous European project LoRe-LCA describes the basic concepts of such models in more detail (report available online). Practitioners should also keep in mind that national EPD programmes may also recommend using toxicity indicators that are not included in the core European PCR (EN 15804 and EN 15978). In this case, the practitioner should use them for national LCA studies (if relevant). This guidance will be précised and updated when the EN 15804/EN 15978 are revised.

G-33 (Buildings) / G-31 (Products) Ionizing radiation indicator

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Aspect G-33 (Buildings) / G-31 (Products) Ionizing radiation indicator
Description
 ‘Ionizing radiation’ is an impact category in LCA related to the damage to human health and ecosystems that is linked to the emissions of radionuclides throughout a product or building life cycle. In the building sector, they can be linked to the use of nuclear power in an electricity mix. LCIA methodologies (such as Eco-indicator99, IMPACT 2002+, ReCiPe) currently calculate the ionizing radiation effect of a product’s or a building’s life cycle.Should an ionizing radiation indicator be used in an LCA of 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 building products screening LCA simplified LCA complete LCA
Provisions Adopt provision of the indicators mentioned in EN 15804 and EN 15978 standards. They do not include an ionizing radiation indicator, because so far no scientifically agreed method is available. Yet, if the goal and scope of the study mention the use of an LCIA indicator for ionizing radiation, then the indicator that is used for the assessment needs to be described.As a proxy indicator, EN 15804 and EN 15978 provide a flow indicator for quantifying the radioactive waste (expressed in m3). This indicator should be used, particularly in a national context that relies heavily on nuclear energy, to avoid shifting of burdens (if only the GWP indicator is used).
Rules from:
 EN 15978:
11. Calculation of the environmental indicators
“Note: Indicators describing emission of ionizing radiation and their impact on human health and/or ecosystems in LCA level are intended for consideration during the revision of this European standard.”

ILCD:
8 Life cycle impact assessment – calculating LCIA results
Provisions: 8.2 Calculation of LCIA results
ILCD Handbook: Recommendations for life cycle impact assessment in the European context
Existing methods for ionizing radiation that can be used at the midpoint and endpoint levels include [Frischknecht 2000]. ILCD states that “to our knowledge this is the only method that meets the general requirements for a quantitative approach. The fate and exposure model has been based on the ExternE work carried out by Dreicer et al., 1995, who described the routine 14 atmospheric and liquid discharges in the French nuclear fuel cycle. Data from UNSCEAR (1993) were used for three additional radionuclides.”
Guidance
 This guidance will be updated when EN 15804 and EN 15978 are revised.

G-34 (Buildings) / G-32 (Products) Water consumption as a new impact category

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Aspect G-34 (Buildings) / G-32 (Products) Water consumption as a new impact category
Description
 The water consumed during the life cycle of a product or a building can have an impact on the environment. This impact actually depends on the geographical location. For example, in some regions of the world, the same amount of consumed water may have different environmental impacts, depending on the available water resources. The current practice in LCA is that water flows are classified only according to their type (ocean, river, groundwater etc.). In this context, should a factor for regional availability be included? Should the scarcity of water be considered? What type of water (e.g. drinking water) should be considered? How should water demand be classified regarding its origin?

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 there is no commonly agreed method for assessing the impact related to water consumption, scarcity of water is not considered at present. The provisions of EN 15804 and EN 15978 should be used, i.e. use of the indicator ‘net fresh water’. Yet, if the goal and scope of the study mention the use of an LCIA indicator for water consumption, the indicator that is used for the assessment needs to be described.
Rules from:
 EN 15978:
11 Calculation of the environmental indicators
EN 15804:
7.2.3 Parameters describing environmental impacts

ILCD:
8 Life cycle impact assessment – calculating LCIA results
Provisions: 8.2 Calculation of LCIA results
Provisions: 7.4.3.6 Resource elementary flows 

Guidance
 1) Practical guidance for the use of EN 15804 indicator
Two cases can be differentiated for guidance: practical calculation of the LCI indicator (currently provided in the CEN TC 350 standards) or available references for the use of a new impact category indicator for water consumption.– If the ‘net fresh water’ indicator is used according to EN 15804 and EN 978, it should be calculated as the difference between the water input and water output from a product system. Thus cooling and turbine-use inventory flows are not to be accounted for in the indicator. Salted water is also excluded, as this category deals only with ‘fresh’ water.


2) Practical guidance for the use of a water indicator as a new impact category
If a water indicator is to be considered as an optional impact category, it has to be documented separately. For more information, please consult the following sources. Results from the UNEP/ SETAC working group ‘Assessment of Freshwater Use within LCA’ (WULCA) should be considered, and are especially relevant. Scientific papers on the latest developments of the water impact category can be also be consulted.

At the standardization level, the ISO is also working on a new standard on water footprint: ISO/CD 14046 Life cycle assessment – Water footprint – Requirements and guidelines.

Revision of this aspect is required if a generally accepted method is available – and used by the EN 15804/15978 standards.

Please also note that some of the EPD programmes consider the inclusion of water in one way or another. Additional information on methodologies can be found in such EPD programmes. However, the various data sources could refer to different methodologies for the calculation of a water indicator.

G-35 (Buildings) / G-33 (Products) Normalization of indicators

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Aspect G-35 (Buildings) / G-33 (Products) Normalization of indicators
Description
 According to the ILCD Handbook, the normalization step refers to the expression of indicators (LCIA, midpoints or endpoints) relative to a common reference by dividing the indicator results by the respective reference value. Different normalization factors can be applied in practice to help the interpretation of results in the building sector. How can this issue be considered within this guidance document?

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 The normalization of indicators (which are the LCA results of products and buildings) should remain an optional stage, according to ISO 14044. However, in certain circumstances the normalization of results may be very helpful for the LCA practitioner and/or the decision-maker, and assist interpretation of the study results. 
Rules from:
 ILCD:
“Provisions: 6.7 Preparing the basis for the impact assessment […]
Normalisation and weighting: […]
XIII) MAY – Results interpretation: Normalisation and weighting are in addition optional steps under ISO 14044:2006 that are recommended to support the results interpretation (see part 6.3.6)”“
Provisions: 10.3 Three levels of reporting requirements […]IV) SHALL – Main report, with the following aspects […]

IV.e) Life cycle impact assessment results calculation, where applicable: […]

IV.e.vi) data and indicator results reached prior to any normalization, grouping or weighting shall be made available together with the normalized, grouped or weighted results.

IV.e) Life cycle interpretation: […]

IV.f.iv) full transparency in terms of value choices, rationales and expert judgements.
Guidance
 If the normalization step is considered for product or building LCA case studies it should be carried out in line with the ILCD Handbook. The assumptions should be documented as transparently as possible. Two types of normalization of results can be used in practice, answering two types of objective:1) Help to identify the most relevant indicators among the global set of indicators
In this case, the LCA results are scaled to a common geographical reference (e.g. at the European level, or in some national contexts) and for a given time period (e.g. 1 year). Generally speaking, normalization factors are available at the world, European and national levels per indicator per year. Doing this will enable the practitioner to identify the key indicators that are driven by the building sector, and in the specific study. It is a way to identify hotspots, and reduce for example the number of indicators from EN 15804/EN15978 or other indicators available in the ILCD Handbook (if relevant). The main issue is to be able to obtain the normalization factors for each indicator. The LCIA method usually provides normalization factors for the midpoint, such as the global warming potential (GWP), or endpoint indicators.For example, the CML 2002 method provides normalization factors for The Netherlands (1997), Western Europe (1995) and the world (1995). Other impact assessment methods, such as Eco-indicator 99, IMPACT 2002 and ReCiPe, also provide normalization values.

Some of these LCIA methods may be used in a building LCA in addition to the baseline indicators given in the EN 15978/EN 15804 standards. Previous European projects have provided the values for these normalization factors through their online deliverables.

Examples of normalization factors that can be used for the French context (mean impacts per person and per year) can be found below:

Mid-pointindicators Unit equiv-person /year Source
GWP kg eq-CO2 8680 CITEPA
AP kg eq-SO2 62.3 CITEPA
POCP kg eq-C2H4 19.7 CITEPA
EP kg eq-PO43- 38.1 IFEN
Other indicators Unit eq-person Source

Primary energy demand

 MJ 48 670 Observatoire de l’énergie

Water consumption

 m3 339 IFEN

radioactive waste

 dm3 0.51 ANDRA

Other wastes

 kg-eq 10400 ADEME

[Peuportier 2008]

Example of normalization factors that can be used for the European context can be found in the BRE Environmental Profiles Methodology.

A comprehensive set of normalization factors are described in detail in LoRe-LCA.

2) Comparison of LCA results with existing benchmarks

In the building sector, practitioners may be asked to comply with a set of targets for overall environmental performance. For example, an architect or a real estate manager may need to answer the following question: “Does the studied building perform well compared with current best and good practice?” In this particular case, the LCA results can be normalized to existing reference values to compare design alternatives with current practice.

Appendix B provides some first reference values for buildings for Germany and France.