Author: Anh-Migrate
G-21 Background databases in LCA studies
| Aspect | G-21 Background databases in LCA studies | |||||
Description |
According to the ILCD Handbook, the background system comprises those processes that are not under the direct control or decisive influence of the producer of the good. For attributional modelling these are typically processes for both the upstream and downstream parts of the entire life cycle of a product. For comparative assertions, the use of consistent background data is crucial. Generally, a product or a building process tree always includes intermediate flows (according to ISO 14044), such as energy, electricity, transport and raw materials. These processes may be modelled using background data available in generic databases. In this context, which database should be used for background data in an LCA study? Which database should be chosen, or which rules should be defined for the use of a database for comparative assertions? |
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related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||
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related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | |
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||
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relevant for |
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| new buildings | existing buildings | building products | screening LCA | simplified LCA | complete LCA | |
Provisions |
All data used in an LCA study should be modelled with a uniform methodology. This can typically be achieved by using a public or commercially available background database and modelling the foreground system in a consistent way.For comparative studies (in simplified or complete LCA studies), it is highly recommended, or even essential, to use datasets that are consistent, e.g. consistent within one database. If this is not possible (e.g. because of data gaps or incomplete documentation), any other data should comply with the methodological rules of the database used for the study. | |||||
Rules from: |
ILCD 9 Life cycle interpretation Provisions: 9.3.4 Consistency check |
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Guidance |
In general, the LCA practitioner should use consistent data from a single source. For European research projects, the use of European databases such as ecoinvent, GaBi, ELCD or ESUCO may be appropriate. The mixing of background data from different databases should be avoided for comparative assertions. This is especially true if data from different databases are not used similarly in the compared models, or if the methodological rules and the quality guidelines do not match between the mixed data.However, in practice the mixing of background data can occur. For example:– if one background dataset (e.g. raw material production, or energy supply) is more representative for the context of the study than the one in the main database being used;– for EPD databases where no mandatory background database is provided. In this case the background data provider should ensure that the use of their data does not lead to bias in the comparative assertions (as the practitioner cannot influence the background data).In general, the use of different background data is not a problem; it is more the adaptation of data in terms of methodology and cut-off rules that can be a problem (for the LCA study). Some databases providing unit process data can easily be adapted to the goal and scope of the LCA study, and to the other background data that cannot be modified, but some databases cannot be adapted in this way.If the lack of specific datasets in a background database leads practitioners to combine data from different literature sources, they need to decide whether it is more important to use a consistent but roughly estimated dataset (and possibly data that are not relevant for the context of the study), or to use a dataset that may be better in terms of representativeness, but which is methodologically inconsistent with the alternative data.In this context, one possible solution is to use data quality indicators for assessing both the representativeness of the data and the consistency of the methodology, compared with the goal and scope of the study: for example, is the dataset compliant with the national context in terms of representativeness? | |||||
G-22 (Buildings) / G-23 (Products) Data quality
| Aspect | G-22 (Buildings) / G-23 (Products) Data quality | |||||
| Description | Generally speaking, the data quality in LCA refers to the relevance of generic or specific LCA data in accordance with the goal and scope of the study. Depending on the background data sources (literature, industry data), and the boundaries and context of the study (e.g. for which purposes or countries are the data being used?), the data quality can be very different within one study. Although data may be of good quality for context Y, this will not necessarily be the case for context Z, as the requirements (e.g. geographical representativeness) may be different. The practitioner should keep in mind that data quality is always a relative concept. In order to point out this aspect as transparently as possible, the quality of the data has to be justified in the context of its use.How should the quality of the LCA data be described, and can the practitioner ensure that data of a specific quality are needed and produced? | |||||
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related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||
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related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | |
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||
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relevant for |
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| new buildings | existing buildings | building products | screening LCA | simplified LCA | complete LCA | |
| Provisions |
The data quality of LCA studies should at least meet the requirements of EN 15978 and En 15804, and the documentation, nomenclature, method and review should be implemented accordingly. | |||||
| Rules from |
EN 15978 10.3 Data quality Different criteria are given in EN 15978, e.g. technological, geographical and temporal coverage (the data should be not older than 10 years). The data should be based on a one-year average (if relevant); check the plausibility and the significance of the data in the final result. EN 15804 6.3.7 Data quality requirements ILCD 6.8 Representativeness and appropriateness of LCI data provisions 12 Annex A: Data quality concept and approach 12.1 Introduction and overview 1) ILCD overall data quality indicators include: technological, geographical, time-related representativeness, completeness, precision/uncertainty, methodological appropriateness and consistency. 2) Data quality documentation aspects cover: documentation, review, nomenclature (e.g. same list of elementary flows) 12.2 Data quality aspects “Representativeness (technological, geographical, time-related) The ILCD Handbook also provides rules for not mixing the data quality aspects (falling under the term ‘accuracy’) with the other concept of ‘precision’ (or ‘uncertainty’). A graphical illustration (see Figure 11) illustrates this point.
Figure 11: Concept of precision ISO 14044
4.2.3.6.2. Data quality requirements
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| Guidance |
In current practice it is usually not possible to choose datasets for quality reasons, but for availability in the construction sector. The practitioner should keep in mind that data quality is crucial for the LCA study. The most appropriate data should be chosen (in terms of representativeness and consistency) as far as possible. Documentation of the used datasets and the quality level is needed as far as possible.The ILCD Handbook provides some recommendations on data quality, depending on the relative significance of the data in the final results. A graphical illustration (see Figure 12) illustrates this point. Figure 12: Focusing efforts on key data
For product LCA, the user of commercial software can also find information on data quality in the documentation for the LCI data used for the process tree of his LCA study. For building LCA, in dedicated LCA software, information on data quality may not be currently available. The practitioner should, however, be cautious when using LCA data (check whether a methodological report is available, check whether a critical review or verification was done, assess whether the data are relevant for the context of the study etc.). In practice, the data quality assessment should be conducted according to the goal and scope of the LCA study. For instance, an LCA study of a building within a European project may require the use of generic European datasets from available LCA databases (ecoinvent, ELCD, ESUCO etc.). By contrast, a screening LCA study in a national context may require the use (if available) of generic national LCA data on building materials, and on components sold on the national market (i.e. representing the ‘consumption mix’ according to ILCD). For building LCA, the data quality assessment can be conducted at two levels: – a data quality check for the entry data (depending on the goal and scope of the study) by means of data quality indicators, e.g. A, B, C, D that may be based on the Pedigree matrix [Weidema 1996]; – a data quality check for the LCA results for buildings (depending on the contribution analysis). In this case, if a building material accounts for 1% of, say, the acidification potential indicator, and the data are not very precise or accurate (e.g. generic data, randomly selected), it does not matter. Conversely, if a key building material (e.g. reinforced concrete) accounts for 45% of, say, the GWP indicator, and the data are not of high quality, the practitioner should possibly refine the LCA data, as it is sensitive to the results. These examples are also valid for LCA data on energy and water processes (e.g. fuel, electric mix, water treatment processes), as they may also drive most of the impacts of a building. |
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5.3 Life Cycle Inventory Analysis (LCI)
5.3 Life Cycle Inventory Analysis (LCI)
G-23 Choice of LCI/LCIA datasets for screening LCA
| 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? | |||||
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Related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||
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Related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | |
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||
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Relevant for |
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| 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. |
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| 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.” |
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| 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. |
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G-22 Data selection for a product LCA
| 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? | |||||||||||||
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related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||||||||||
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related study phase |
☒ | ☐ | ☐ | ☐ | ☐ | |||||||||
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||||||||||
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relevant for |
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| 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: |
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| 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. |
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G-24 Choice of LCI/LCIA datasets for simplified LCA
| Aspect | G-24 Choice of LCI/LCIA datasets for simplified LCA | |||||||||
| Description |
Different LCI/LCIA 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 LCI/LCIA data can be used in practice, depending on their availability not only 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 simplified LCA? | |||||||||
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Related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||||||
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Related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | |||||
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||||||
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Relevant for |
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| new buildings | existing buildings | construction 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 simplified LCA.In contrast with screening LCA, the data should reflect more closely the building element, product or material. They can either represent a full building component (e.g. 1 m2 concrete block wall insulated with wood wool), a building product (e.g. 1 m2 of rockwool) or a building material (e.g. 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 simplified 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. 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. |
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| Rules from: |
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| Guidance |
In practice, the LCA data for a simplified LCA should represent the building elements, products or materials more closely than the data used for a screening LCA. 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 building components can correspond to generic typical components using default values for the major 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 parts 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 e.g. 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 or 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 level) include, for example, the ELCD, ESUCO and ecoinvent databases. 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. |
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G-25 Choice of LCI/LCIA-datasets for complete LCA
| Aspect | G-25 Choice of LCI/LCIA-datasets for complete LCA | |||||||||
| Description |
Different LCI/LCIA 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 or complete), different LCI/LCIA 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 building materials, products and processes). How can this be addressed for complete LCA? | |||||||||
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Related study objective |
☒ stand-alone LCA | ☒ comparative assertion | ||||||||
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Related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | |||||
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | ||||||
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Relevant for |
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| new buildings | existing buildings | construction products | screening LCA | simplified LCA | complete LCA | |||||
| Provisions |
The LCA practitioner or the user of dedicated building LCA tools should use adapted data for description of the building components in complete LCA. In contrast with simplified LCA, the data should reflect the building element, product or material more closely. They can represent a full building component (e.g. 1 m2 concrete block wall insulated with wood wool), or a building product (e.g. 1 m2 of rockwool) 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 complete LCA for the construction site, the operational energy and water uses, and the deconstruction activities are described in the corresponding aspects.LCA data for the building products cited above should correspond to specific industry data (e.g. EPD data) provided by the building manufacturers at the European level, or also in the national context; generic or average LCA data (refer to the provisions for simplified LCA) should be used if specific data (e.g. EPD) are currently missing for some building products or technical equipment.Cut-off rules and impact categories may be considered according to the ILCD Handbook if the goal of the study is to assess indicators and data beyond the EN 15804 cut-off and impact category. The practitioner is likely deviate from the above provision and use instead generic or average datasets providing a high level of detail in terms of the cut-off and impact categories to be calculated. | |||||||||
| Rules from: |
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| Guidance |
In practice, the LCA data for a complete LCA should closely represent the building components, products or materials, or the part of the building. The building LCA practitioner may use an existing national EPD database to collect specific EPD data on building products, depending on the requirements. Three different practical recommendations can be given for the use of data on building elements, the associated LCA data, and the currently available specific (e.g. EPD) databases.1) Practical guidance for the use of data describing the building elements
The data describing the building components should correspond to the components implemented in the building. Please refer to the description of the complete LCA study type for more information. Other data include building products and materials LCA data. These ‘raw’ data usually serve when deriving data for building components or parts of the building. Consistency should be ensured between the different levels of data for complete LCA (part of the building, components, products and materials). 2) Practical guidance for the use of specific LCA data for a European or national context ILCD provisions can be consulted concerning the consumption mix of the building product. Specific data such as EPD reflects the production volume of a building product sold on a national market. 3) Practical availability of specific (e.g. EPD) databases in Europe that can be used by the practitioner Specific EPDs may be found in available national EPD databases or European EPD databases (e.g. ECO-EPD). Examples of such databases can be found several European countries: France: INIES Germany: Institut Bauen und Umwelt UK: BRE Profiles Spain: DAPc system The Netherlands: MRPI Finland: RTS The International EPD (R) ‘The Green Yardstick’ also provides EPD data for some European countries, such as Sweden and Italy. If specific EPD are not available, the practitioner may use generic data or average industry data. Consultation of the LCA Resources directory of the European Commission – Joint Research Centre, section ‘Databases’ may be then needed. Generic databases include, for example, the ELCD, GaBi and ecoinvent databases. Other generic databases developed in European countries include, for example, the German Ökobau.dat and the Swiss Catalogue Construction/KBOB databases. Care has to be taken when using EPDs for complete LCA, as they may not include a full LCI (depending on the PCR, only environmental indicators may be required). Thus they may not allow the use of LCIA indicators outside the scope of the Product Category Rules. For example, the EN 15978 standard does not yet include land use, toxicity or ecotoxicity indicators. The same remarks apply to cut-off rules and infrastructures issue. The LCA practitioner should be aware here that the choice of LCI/LCIA datasets for complete LCA is intended primarily to be as accurate as possible for the current impact of the manufacture of a building product. However, the cut-off rules and LCI documentation may not be as comprehensive as needed by the practitioner. For alternative goal definition beyond the scope of EN 15804, the practitioner may need a complete LCI in order to consider a full suite of impact categories. The same applies for the cut-off criteria. In this special case, the practitioner is likely to rely on generic datasets that may be the only possible way to provide such a level of detail (LCI, cut-off rules). At this point, there is a trade-off between using specific data for a commercial reference of a product, and maintaining a high level of detail in terms of LCI, cut-off rules etc. |
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G-26 Use of building physical description data
| 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? | ||||||
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Related study objective |
☒ stand-alone LCA | ☒ comparative assertion | |||||
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Related study phase |
☐ | ☒ | ☐ | ☐ | ☐ | ||
| goal and scope definition | inventory analysis (LCI) | impact assessment (LCIA) | interpretation | reporting | |||
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Relevant for |
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| 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
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| 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. | ||||||
5.4 Life cycle impact assessment (LCIA)
5.4 Life cycle impact assessment (LCIA)
- G-27 Choice of environmental indicators – screening and simplified LCA.
- G-28 Choice of environmental indicators – Complete LCA.
- G-29 Abiotic resources depletion indicator
- G-30 Land use indicator
- G-31 Biodiversity indicator
- G-32 Human toxicity and ecotoxicity indicators
- G-33 Ionizing radiation indicator
- G-34 Water consumption as a new impact category.