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C-02 Demolition/deconstruction – complete LCA

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Aspect C-02 Demolition/deconstruction – complete LCA
Description
 The deconstruction and demolition stage involves quantification of the impact related to the end of life of the constructed system. For example, if it is a reinforced concrete building, deconstruction activity will consist mainly in separating the reinforcing steel from the concrete. During this operation, energy is consumed, and pollutants are emitted to the air. In this context, should the demolition and deconstruction stage be considered in the context of a complete 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 demolition and deconstruction aspects should be included for a complete LCA. Generic or specific data should be taken from LCA databases or other relevant sources if available, unless they fall under cut-off rules.
Rules from:
 EN 15978:
8.7.2 Scenarios for deconstruction – Module C1

EN 15804:
6.2.6 C1-C4 End-of-life stage information modules
Guidance
 The practitioner should use detailed calculation (based on specific data) for a complete LCA. The energy, materials and related emissions of these processes should be included. However, very few LCA data are currently available in every national context. One option is to use existing generic LCA data on the impact of demolition and the deconstruction process (e.g. the impact of sorting the reinforcing steel from the concrete at the end of life of the building). Such generic LCA data can be found e.g. in the Ecoinvent database or in the Greenest Building, which provides indicative demolition energies for various building types (see exhibit 2). The practitioner should be aware that the data on demolition process may not be fully adapted to the context. Another option is to define generic data with stakeholders (collection of specific data). For most construction projects this aspect is likely to fall under the cut-off rules, and may be omitted.

8.3 Module C2

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No specific aspects are given for Module C2 for buildings, as it is likely to be predefined in building LCA studies, e.g. by the use of EoL generic processes and cradle-to-grave EPD, which have already taken this aspect into account.

Please refer to the two following aspects of the EeBGuide – Part A: PRODUCTS guidance document for further information, as well as the EN 15978 standard.

8.4 Module C3

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No specific aspects are given for Module C3 for buildings, as it is likely to be predefined in building LCA studies e.g. by the use of EoL generic processes and cradle-to-grave EPD, which have already taken this aspect into account, as well as the EN 15978 standard

Please refer to the following aspect of the EeBGuide – Part A: PRODUCTS guidance document for further information, as well as the EN 15978 standard.

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C-03 (Buildings) / C-08 (Products) LCA modelling of landfill/disposal

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Aspect C-03 (Buildings) / C-08 (Products) LCA modelling of landfill/disposal
Description
 Should general rules be defined regarding what is deposited and which LCA data to use? What is the timescale for modelling the fate of disposed material?

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 This aspect depends on the background database used. LCA practitioners need to adopt the procedures from the background database, and have no specific influence on it.The fate of materials should be based on current practice (as a baseline scenario), and not predicted practice in the future (except for sensitivity analysis purposes).
Rules from:

EN 15978

 8.7.5 Scenarios for disposal – Module C4

EN 15804

 6.3.4.6 End-of-life stage
6.3.7 Data quality requirements
6.3.8 Developing product scenarios
7.3 Scenarios and additional technical information
7.3.4 End-of-life
ILCD Provisions 7.4.4.2 Modelling waste treatment
I) SHALL – Waste and end-of-life product deposition
I.a) Model waste management completely
         I.b) Modelling discarding of goods into nature
I.c) Modelling waste as output“Note: the use of generic waste treatment models/processes may be considered to limit time and resources required for data collection.”
Guidance
 Within building or product LCA studies, the depositing of material in landfill or other disposal mechanisms is typically not a focus of the study, and is modelled with the use of generic data from background databases. These databases have their own modelling principles concerning the fate of landfilled material. The practitioner cannot influence this aspect, but should understand the way in which landfill processes have been modeled. In some databases, emissions that occur after 100 years are identified separately, and their effect can therefore be considered separately. Databases may also have specific assumptions about the decay rates of biogenic material in landfill and the composition and capture rates for landfill gas, which may not relate to practice in the various Member States, or to current understanding. The practitioner should ensure that this aspect is not neglected. For example, organic materials should not be handled as though they were inert, as this might yield significant errors in the estimation of the fate of deposited material. The practitioner should ensure that the treatment of landfill and incineration processes is considered consistently with the datasets for the production of biogenic material (this should be the case if data are sourced from the same database). Module C4 covers the disposal of end-of-life construction material arising from the demolition of the building. The disposal of end-of-life material arising from the use phase (Modules B2–B5) is included in the individual module where the waste arises.Current landfilling rates and other disposal processes should be used to develop the scenarios for Module C4.The choice of LCA data for landfilling should correspond, as a minimum, to the different types of wastes (inert, non-hazardous and hazardous), although more detailed landfill models are available in many databases. In addition, the time period over which inputs/outputs should be inventoried from the point of disposal in landfill is 100 years [EN 15804 6.3.7]. For biogenic materials, it is of particular relevance to take account of the fate of the biogenic carbon when landfilled, considering the decay rate, the mix of carbon dioxide and methane produced from decay, and the landfill gas capture rate of the landfill. National assumptions for various materials and landfills vary widely.The extent to which biogenic carbon decays into methane at end of life also needs to be considered in LCA studies, although there is little consensus on exactly how much methane will be generated or released in an average landfill. In any event, the greenhouse gases released from biomass degradation will not be balanced by an equivalent amount of sequestered CO2, owing to the increased GWP of methane emission. National EPD programmes may prescribe landfill models, or the percentage of material that will be placed in landfill at the end of life.

D-01 Inclusion of reuse, recovery or recycling potentials (Module D) in building or product LCA

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Aspect D-01 Inclusion of reuse, recovery or recycling potentials (Module D) in building or product LCA
Description
 Module D describes the net benefits related to exported energy and secondary materials, secondary fuels or secondary products resulting from reuse, recycling and energy recovery that take place beyond the system boundary for both products and buildings. Displaying Module D separately is a very recent outcome of expert discussions. Before, in some life cycle studies, Modules C (end of life) and D were presented jointly in one life cycle stage, and different approaches were used in other situations such as the use of recycled material. As this is not necessarily done any more, under what circumstances is it necessary or mandatory to include Module D in the life cycle results?

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 EN 15978 for building level calculation states [8.8] that “If relevant and available, Module D addresses the net environmental benefits or loads resulting from reuse, recycling and energy recovery”, and [12.6] “The communication from the report may be simplified according to the following rules: […] if relevant information is provided at the product level on Module D, this information should be reported.”The first point states that Module D should be included if it is relevant, and data are available. The second suggests that if any product used in the building provides data for Module D, this must be reported at the building level, although this is not a mandatory requirement of the standard (‘should’, not ‘shall’).

In general, Module D should be reported both on the product and at the building level, but it is clear from both EN 15804 and EN 15978 that Module D is provided “to help with transparency on the benefits and loads of processes beyond the system boundary of the object of assessment”. Deviating from EN 15978 for benchmarking purposes with other studies where recycling credits have been included, Module D may be included in the building life cycle, but other aspects of system boundary and treatment of recycling (such as use of the cut-off approach for inputs) may render such comparisons invalid.
Rules from:

EN 15978

 7.4.6 Boundary for the benefits and loads beyond the system boundary (Module D)

EN 15804

 6.2.7 D Benefits and loads beyond the system boundary, information module

ILCD

 ILCD uses different approaches for the system boundaries and the benefits of recycling, and Module D is therefore not discussed.
Guidance
 If Module D data are not provided by manufacturers within the EPD, default values can be used, or values estimated by the building assessor. As these values may be worse than the calculated values for the product, this could be an incentive for producers to provide data at a product level.It could be argued that Module D is not relevant to the life cycle assessment of both products and buildings, as it is outside the system boundary, although the TC 350 standards state that Module D can be provided as part of the building assessment information to provide additional transparency on benefits and loads beyond the system boundary.

The benefits of exported energy (for example from excess generation from integrated renewable, or from the capture of landfill gas from disposal in C4) must be reported in Module D, and this must be reported separately from any other flows, but Module D is an optional module for any product EPD, and at the building level EN 15978 states regarding Module D that “Where a material flow exits the system boundary and has an economic value or has reached the end-of-waste stage and substitutes another product, then the impacts may be calculated” [7.4.6], and 8.1 states “If information on Module D is communicated in a building assessment”, which shows that it is not a requirement that it be communicated. It is clear that Module D does not need to be calculated for all materials; only where this is defined at a product level must it also be considered in Module D at the building level. However, depending on the relevance of and attitude to the information provided in Module D, practitioners are free to generate data within Module D for products that have not provided this information within their EPD, subject to the normal rules for scenarios regarding current practice.

The system boundary for the building life cycle may be extended to include Module D if full life cycle results are assessed in a context where credits due to system expansion are typically accounted for. This is, for instance, the case in the German Sustainable Building labelling system (DGNB). The practitioner should be very clear that changing the system boundary of the object of assessment may introduce the possibility of double-counting benefits or loads, and should ensure this does not occur.

The other use of Module D is to assess design for dismantling or recycling building alternatives.

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D-02 Reuse – water consumption

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Aspect D-02 Reuse – water consumption
Description
 There are different quality levels of water – freshwater, rainwater, greywater and waste water. Depending on these quality levels water, can be used for different applications (e.g. rainwater for washing clothes). How and under what circumstances is it possible to obtain benefits from the reuse of water?

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 Module D looks at the loads and benefits of the net output flow, if relevant and available. If water outputs or any output flow at EoL (not production waste) are reused, then to calculate the net output flow, any use of similar reused water or material as an input in Modules A1–C4 must be considered to calculate the net flow (output − input = net output flow).If there is a net output flow, then the impacts associated with any reuse processes after the ‘end-of-waste state’ can be included in Module D, together with a credit associated with the avoided production of the virgin product.
Rules from:

EN 15978

 7.4.6 Boundary for the benefits and loads beyond the system boundary (Module D)

EN 15804

 6.2.7 D Benefits and loads beyond the system boundary, information module

ILCD

 Not mentioned
Guidance

If any water from the building is reused outside the building, then the benefits of this use (credit for virgin water extraction and treatment, together with any impacts from the system boundary before substitutive use) are included in Module D.

If a waste material or waste energy is recycled, then the impacts associated with any processes after the ‘end-of-waste state’ before it can be used to substitute primary material can be included in Module D , together with a credit associated with the production of the virgin product it substitutes.

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D-03 Credits for recycling and energy recovery

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Aspect D-03 Credits for recycling and energy recovery
Description
 How should credits for recycling and energy recovery be allowed for?

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 Where recycled material or energy recovered at end of life are also used in the production of products (A1–A3), in Modules B1–B5 or C1–C4, then the net output flow is calculated as total output − total input.If there is a net output flow that provides benefits beyond the system boundary (as it produces material or energy that substitutes for virgin production), then the processes beyond the system boundary required to produce the recycled material or recovered energy substituted can be provided in Module D, together with a credit calculated by deducting the impact of producing the material or energy from virgin resources. For materials, this will be the virgin production route. For energy, this will be the use of the typical energy mix for heating (for heat energy) or the grid mix (for electrical energy), excluding secondary energy. In practice, unless energy from waste is a significant part of the energy or grid mix, the national mix can be used.
Rules from:

EN 15978

 7.4.6 Boundary for the benefits and loads beyond the system boundary (Module D)
8.8 Scenarios for benefits and loads beyond the system boundary – Module D

EN 15804

 6.2.7 D Benefits and loads beyond the system boundary, information module

ILCD

 Not mentioned
Guidance
 If the recycled product cannot substitute the primary product completely (e.g. it has 95% of the relevant functional equivalence), a justified value correction factor should be used to reflect this in the credit calculation.If waste is burned with less than 60% energy recovery, it has to be classified as a disposal process rather than a recovery process, and the process must be reported in Module C4. There may still be benefits for the production of energy beyond the system boundary that can be shown in Module D (as with landfilling and the recovery of gas from landfilling).

For example, if there was a net output flow of electricity, then the grid mix of electricity (excluding any secondary energy sources) should be used to credit the flow.

Note that the incineration of waste (i.e. material that is considered waste because it has not reached the end-of-waste state) may also be more efficient than 60%, but it must still be considered as a disposal process.

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9 Aspects concerning Module D – Benefits and loads beyond the system boundary

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This chapter addresses aspects that are related to life cycle stage D. All the aspects of this chapter provide provisions, rules and guidance for the goal and scope definition and the inventory analysis steps according to [ISO 14040] and [ISO 14044].

Module D makes it possible to quantify the reuse, recovery and recycling potential of a building or a building product. This module may be of interest in assessing and comparing designs for dismantling, or designs for recycling alternatives.

The following list describes the addressed aspects in Module D.

10 Discussions and perspectives

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In this chapter some of the findings of the project are discussed, connections to other research projects are made, and possible future developments of the EeBGuide guidance document are addressed.

The original aim of the EeBGuide project was not to develop new provisions or even standards for LCA, but to summarize existing provisions from the European standards and the ILCD Handbook, and give guidance on important LCA topics. This guidance is based on the latest LCA practitioners’ experience, and on findings from the EeBGuide project partners’ research and development activities, as well as from other European research projects. LCA practitioners now have a document that gives provisions for and guidance on the critical and most relevant aspects of conducting an LCA study for buildings and building products.

The EeBGuide project’s methodological approach was to combine both the CEN TC 350 and ILCD provisions. In this context, the guidance document remains as transparent as possible by linking to original rules from these reference documents and the chosen provision and guidance. The reference documents sometimes conflict. As far as possible, provisions from CEN TC 350 were applied, but if no provisions were given there, then the ILCD Handbook provisions were also considered (e.g. for consequential modelling). In some cases, both provisions (from CEN and ILCD) were considered, as they provide complementary rules that fulfil different goals and scopes for product or building LCAs (e.g. for the choice of environmental indicators). However, more work will be needed to analyse in greater detail the implications of ILCD provisions when applied to product and building LCA studies. The need for growing consistency between standards and ILCD documentation, however, was obvious throughout the project.

The EeBGuide guidance document is a new contribution to an existing set of documents providing operational guidance for building LCA studies. For example, two previous European research projects (LoRe-LCA and ENSLIC Building) can be also considered relevant sources of information for the LCA practitioner. They provide complementary guidance for some of the aspects covered in the EeBGuide. As far as possible, existing guidance from these projects was reported in the EeBGuide, e.g. by referring to online documentation or deliverables. However, not all of the aspects addressed in the EeBGuide guidance document were covered in these two previous European projects.

Indeed, the main innovation of the EeBGuide guidance document, compared with these previous projects, is to bring together  in a structured document some of the latest findings from the LCA and construction community. More than 150 aspects have been identified to be taken into account for a product or a building LCA. They are structured according to the LCA framework: i.e. goal and scope definition, inventory analysis, impact assessment, interpretation and reporting. This allows any LCA practitioner not necessarily aware of the specific wording of the CEN TC 350 standards to easily go through the document and identify the appropriate rules to follow. At the same time, the aspects are classified according to the life cycle stages of the EN 15804 and EN 15978 standards (Modules A, B, C and D). The provisions and guidance are broken down according to the study types (screening, simplified and complete LCA) so as to allow the practitioner to easily identify the main recommendations according to the stage of a project. The EeBGuide guidance document makes a distinction between stand-alone LCA and comparative assertions. This difference is very important, as comparative studies require more consistency to ensure that the results are not biased. The EeBGuide guidance document also distinguishes provisions for new buildings from those for existing buildings, as the LCA studies will not refer to the same goal and system boundaries. Reporting and review templates for case studies are also part of the guidance.

It is notable that some outcomes of the discussions of the EeBGuide project – within the consortium, with LCA experts, within the public consultation and with the review panel – proved relevant for the value of this document. Among the most important contributions to the general discussion of LCA in construction, the separation of operational guidance between product LCAs and building LCAs – and at the same time the assurance of consistency of these provisions – is one of the most relevant findings. In addition, the formulation of the concept of different study types – screening LCA, simplified LCA and complete LCA – in line with rules on when to apply which study type for what purpose, and how and what to include and exclude, reflects a common need of practitioners. The value of these concepts is given with the fact that the LCA community may now refer to uniform rules on how to conduct studies of the different types.

To summarise, the EeBGuide guidance document takes into account not only the latest findings of recent European projects and research and development works conducted at, for example CSTB (Environment department), Fraunhofer (IBP-GaBi department), PE International, the UNESCO Chair in Life Cycle and Climate Change at the University of Barcelona, and BRE Global, but also current provisions from the standards of CEN TC 350 and the ILCD Handbook. Finally, the EeBGuide guidance document is one of the first contributions at the European level towards a merging of relevant provisions from ILCD and CEN TC 350 in a consistent way. The EeBGuide partners believe that such a consistent guidance document provides a highly operational yet scientifically sound document for the building sector. The EeBGuide guidance document can now be used by the primary audience (LCA practitioners within E2B EI projects) and the secondary audience (building LCA tool developers and certification schemes).

As it is the first comprehensive contribution with the goal of merging diverging reference documents for different study types, the partners remain aware that many research topics still have to be conducted in the near future to support and more precisely specify the different definitions and guidance given as a first step in this guide. If there are any follow-on research projects in this direction, the results could be included in a new version of the EeBGuide. Also if there are new developments or outcomes from the standardization work or the ECO platform, these results will have to be incorporated in the guidance document as well. The EeBGuide guidance document has also identified issues that are not completely resolved when applying the CEN TC 350 standards. It may be a useful document for the standardization committee when revising the EN 15804/EN 15978 standards.

Further outcomes of more operational projects, such as the SBA Common Metrics project, have to be considered as very important contributions next to the EeBGuide guidance document to ensure comparability within different LCA studies. Future research projects should also focus on a common European reference building as a baseline scenario. Here, the most important parameters should be investigated (e.g. reference study periods, main EoL scenarios for materials, etc.) in order to define a European baseline scenario, providing average European values for its parameters, which will facilitate comparisons between research projects, and support the evolution of building labelling schemes.