Life cycle assessment methodologies in the construction sector - circe

Life cycle assessment methodologies in the construction sector:
the contribution of the European LORE-LCA project
Summary
Bruno Peuportier
Senior Scientist
MINES ParisTech
France
bruno.peuportier
@mines-paristech.fr
Gregory Herfray, MINES ParisTech, France,
gregory.herfray@mines-paristech.fr
Tove Malmqvist, KTH, Sweden,
tove.malmqvist@abe.kth.se
Ignacio Zabalza, CIRCE, Spain, izabal@unizar.es
Heimo Staller and Wibke Tritthart, IFZ, Austria,
staller@ifz.tugraz.at and tritthart@ifz.tugraz.at
Christian Wetzel, CALCON, Germany,
c.wetzel@calcon.de
Zsuzsa Szalay, EMI, Hungary,
zsuzsa.szalay@yahoo.com
LORE-LCA is a European research coordination action dealing with the application of life cycle
assessment (LCA) in the construction sector. One activity is to analyse existing methods, including
standards and guidelines, in order to establish a consensus by identifying good practice, and to list
knowledge gaps for which further investigation is needed.
Keywords: Building life cycle assessment, European research coordination action
1. Introduction
The first generation of green building certification schemes has been elaborated in the 90’s,
generally by organizations gathering policy makers and professional representatives. In parallel,
scientists developed tools, mostly based upon LCA, aiming at a better understanding of how
environmental impacts are generated, and proposing some aid to designers. Building LCA tools
have been improved and are now integrated in certification schemes like LEED, BREEAM, DGNB,
HQE etc.
Still, limitations in LCA have been analysed and several methodological aspects are differing
among the existing tools. Harmonization could help to increase the confidence in such models. At
a European level, the LORe-LCA (“Low Resource consumption buildings and constructions by use
of LCA in design and decision making”) research coordination action gathers research institutes,
technical organisations and professionals in order to progress towards a more harmonized
application of LCA in the building sector. This project includes 5 tasks : a) analysis of LCA – use
and barriers, b) Life cycle assessment methodologies, c) LCA as practical tool in design, d)
Interpretation of LCA results and, e)Training and dissemination.
The present communication relates to the second task. The subject is to analyse existing LCA
methods applied in the building sector. Most methodological choices depend on the objective of an
LCA study, therefore recommendations have also been elaborated according to the concerned
actors and purposes of performing an LCA.
2. Analysis of Building LCA methodologies
System description has first been studied, including: functional unit, system boundaries and
processes, cut off rules. Methods for simplification and adaptation of LCA to the construction sector
have been proposed like the use of default values, a simplified building description, and dynamic
LCA (e.g. to account for peak electricity demand induced by buildings). Questions have been

examined regarding the elaboration of life cycle inventories, and particularly the minimal list of
substances needed for a proper impact assessment, accounting for indoor emissions, data quality,
and the use of European, national or local data. Specific methodological aspects have then been
addressed concerning how to model biogenic CO2 (e.g. carbon balance of timber elements), coproducts,
end of life scenarios and recycling. The definition of environmental indicators, particularly
regarding resources, has finally been examined as well as normalisation.
The different aspects listed above show that research is still needed in order to progress towards a
consensus and harmonization of different approaches.
3. Elaboration of recommendations for different actors
3.1 Tool developers
It is first advised to integrate existing knowledge like ISO standards on LCA, future CEN standards
regarding applications in the building sector, guides elaborated by the International Reference Life
Cycle Data System (ILCD), European projects and literature.
Adapting the tools to professional practice may lead to give the choice between using default and
generic (or average) life cycle inventories at early design phases, then more specific EPDs to
compare products during detailed design. Interpretation is probably one of the steps requiring the
most expertise. Sensitivity studies are also needed to check the robustness of the results in terms
of assumptions (e.g. life span, modelling choices etc.). For validation purposes, it is suggested to
perform the benchmark study elaborated in the frame of the European thematic network PRESCO
(Practical Recommendations for Sustainable Construction).
3.2 Recommendations to users
The main application of LCA in the building sector is related to the design phase, allowing various
architectural and/or technical choices to be compared by design teams. But LCA can also be
applied in earlier phases, e.g. to compare different possible building sites, or to select a project in
the frame of an architectural competition. Elaborating a programme before the competition,
including environmental targets, can also benefit from LCA, which may even be used for policy
making. LCA can also be used as urban design aid, e.g. to compare different street and building
orientation, compactness, number of storeys etc. LCA is as well used by manufacturers in order to
elaborate data on building products in the form of ISO-type III environmental declarations. Some
work is performed to harmonize the application of LCA in the building and infrastructure sectors,
allowing e.g. the urban level to be addressed.
4. Conclusions and perspectives
Accounting for environmental issues in the building and urban sectors is presently based upon
rather subjective approaches. Yet the severity and planetary extent, long duration and possible
irreversibility of environmental impacts like global warming, nuclear risk, dispersion of toxic
substances, biodiversity loss and resource depletion, justifies more precise tools to be used in the
decision making process. LCA is presently the method incorporating the most knowledge, and is
increasingly considered in e.g. labelling or certification schemes. Knowledge gaps have still been
identified and harmonization work is needed regarding some methodological aspects like modelling
recycling and biogenic CO2. The LORE-LCA guidelines report is circulated among Building LCA
experts in order to get feedback regarding the identification of good practice and recommendations
to users and tool developers. Improving LCA tools and applying them in decision making would
help building actors to contribute in the reduction of environmental impacts in this sector, with a
possible extension to urban scale.

Life cycle assessment methodologies in the construction sector:
the contribution of the European LORE-LCA project
Summary
Bruno Peuportier
Senior Scientist
MINES ParisTech
France
bruno.peuportier
@mines-paristech.fr
Gregory Herfray, MINES ParisTech, France,
gregory.herfray@mines-paristech.fr
Tove Malmqvist, KTH, Sweden,
tove.malmqvist@abe.kth.se
Ignacio Zabalza, CIRCE, Spain, izabal@unizar.es
Heimo Staller and Wibke Tritthart, IFZ, Austria,
staller@ifz.tugraz.at and tritthart@ifz.tugraz.at
Christian Wetzel, CALCON, Germany,
c.wetzel@calcon.de
Zsuzsa Szalay, EMI, Hungary,
zsuzsa.szalay@yahoo.com
LORE-LCA is a European research coordination action dealing with the application of life cycle
assessment (LCA) in the construction sector. One activity is to analyse existing methods, including
standards and guidelines, in order to establish a consensus by identifying good practice, and to list
knowledge gaps for which further investigation is needed.
System description has first been studied, including: functional unit, system boundaries and
processes, cut off rules. Methods for simplification and adaptation of LCA to the construction sector
have been proposed like the use of default values, a simplified building description, and dynamic
LCA (e.g. to account for peak electricity demand induced by buildings). Questions have been
examined regarding the elaboration of life cycle inventories, and particularly the minimal list of
substances needed for a proper impact assessment, accounting for indoor emissions, data quality,
and the use of European, national or local data. Specific methodological aspects have then been
addressed concerning how to model biogenic CO2 (e.g. carbon balance of timber elements), coproducts,
end of life scenarios and recycling. The definition of environmental indicators, particularly
regarding resources, has finally been examined.
Keywords: Building life cycle assessment, European research coordination action
5. Introduction
The first generation of green building certification schemes has been elaborated in the 90’s,
generally by organizations gathering policy makers and professional representatives. In parallel,
scientists developed tools, mostly based upon LCA, aiming at a better understanding of how
environmental impacts are generated, and proposing some aid to designers. Building LCA tools
have been improved and are now integrated in certification schemes like LEED, BREEAM, DGNB,
HQE etc.
Still, limitations in LCA have been analysed [3] and several methodological aspects are differing
among the existing tools [11]. Harmonization could help to increase the confidence in such models.
At a European level, the LORe-LCA (“Low Resource consumption buildings and constructions by
use of LCA in design and decision making”) research coordination action gathers research
institutes, technical organisations and professionals in order to progress towards a more
harmonized application of LCA in the building sector. This project includes 5 tasks :
• analysis of LCA – use and barriers
• Life cycle assessment methodologies
• LCA as practical tool in design
• Interpretation of LCA results
• Training and dissemination

The present communication relates to the second task. The subject is to analyse existing methods,
including standards and guidelines, in order to establish a consensus by identifying good practice,
to derive recommendation for tool developers and users, and to list knowledge gaps for which
further investigation is needed. Most methodological choices depend on the objective of an LCA
study, therefore recommendations have been elaborated according to the concerned actors and
purposes of performing an LCA.
6. Analysis of Building LCA methodologies
6.1 System description
The functional unit commonly includes information regarding a quantity (e.g. building designed for
90 residents), a function (e.g. providing space for living and/or working in a specific location), the
quality of this function (comfort level, quality of life), and a duration (e.g. 80 years). Comparing
different buildings (for instance in an architectural competition) requires that at least the major
functional requirements, intended use and relevant specific technical requirements are well
described, in order to enable transparent comparison. If buildings of different size or life span are
compared (e.g. benchmark with reference and best practice values), a reference flow can be used,
e.g. 1 m 2 of residential building during one year, or providing 1 person with dwelling during one
year.
Four stages are usually considered in the life cycle of a building:
Production: Supply of raw materials, transport needs and manufacturing processes from cradle to
gate for the construction products, energy systems, etc.
Construction: Transport of the construction products and energy systems from the manufacturing
plant to the building site, transport and energy demand of the construction equipment and wastes
of the construction process.
Use: Operational energy use for heating, cooling, DHW and lighting, contribution of the renewable
energy systems, operational water use, maintenance, repair and replacement, etc.
End of life: Demolition of the building and disposal of each building product, possibly recycling.
The system is therefore larger than the studied building: it includes the fabrication and transport of
building products, water, electricity and heat, waste treatment etc. This is necessary in order to
avoid problem shifting, e.g. replacing local emissions in a boiler by impacts related to electricity
production.
In principle, when performing LCA calculations, all building components and their impacts that
occur within the building or within the selected scope need to be taken into consideration. However,
in practice, it can be observed that not all the material flows of a building can be covered in an LCA
because of insufficient time or incomplete data. Cut off rules have therefore been defined, but
research could be performed in order to establish a system to identify the influent material flows in
a particular building, enabling to justify adequate cut off rules.
A similar approach can be conducted for roads, and a system description has been proposed.
6.2 Study of simplification and adaptation of LCA applied to buildings
A comprehensive LCA study requires a large amount of data. It can be performed for an industrial
product which is fabricated in large series, but it is not compatible with professional practice in the
building sector: most buildings are unique and a lot of evaluations have to be performed during the
design phase, therefore only a limited time can be dedicated to LCA, which imposes to simplify the
process.
Simplified LCA tools have been developed as spreadsheets. Linking LCA to a CAD system,
allowing geometrical data to be used and material quantities to be automatically evaluated is
helpful, as well as linking LCA to e.g. energy calculations. Simplified tools focus on heavy structural
elements, but some components may induce non negligible impacts even if they are present in

small quantities (e.g. painting). The relative contribution of a material in the global environmental
impact of a building depends on the selected indicators: an element may have a negligible impact
on e.g. CO2 and waste indicators, but a high contribution regarding toxicity. Simplification of LCI
data and building description therefore requires a careful sensitivity study, depending also on the
objective of the LCA study [9]. It is therefore recommended to continue some research activities on
this topic.
In an early design phase, some data is still missing, though LCA is very useful at this moment
when the decisions made influence most the environmental balance of a building. LCA is more
precise at the end of the design phase, when detailed information is available regarding the
components, producers, transport distances etc. But it is less useful because all decisions have
already been made. A solution to allow LCA to be performed at early design phase is the use of
default values. For instance a default wall composition and glazing characteristics can be
considered when studying the architectural shape of the building. Defining such default values is
still to be done, though it is not really a research activity but requires rather a collective
development by the concerned actors.
Most building LCA tools neglect temporal variation of LCI data. For processes like electricity
production, impacts may vary a lot due to seasonal, weekly and hourly peak demand. High winter
consumption for space heating (e.g. heat pump) and a summer production (e.g. photovoltaic
system) may not be equivalent to a low electricity consumption (e.g. gas boiler) and no production.
Research is needed to progress on this aspect, which is also related to the choice between
attributional or consequential LCA [4]. The attributional approach assumes that the studied system
(e.g. a building) has a negligible effect on the background system (e.g. electricity production). But if
e.g. 75% of the new buildings are heated by electricity in a country, this has globally an impact on
the electricity production mix so that the consequential approach may be preferred. But this
approach is much more complex and would require additional knowledge.
6.3 Study of life cycle inventories
Many producers of building components are SMEs, and cannot easily commission a specialised
consultant to perform a detailed LCA. Imposing a very detailed format for life cycle inventories (LCI)
would not permit to get data for most low impact materials which are mainly produced by small
companies, so that data would only be available for standard materials. On the other hand, too
simplistic LCI data would not allow issues like toxicity and biodiversity to be evaluated. At the
moment, the number of substances provided in LCIs varies between around 10 et around 1,000.
This is to be compared with the estimated 100,000 substances available on the market.
Another simplification in LCI data is spatial averaging of emissions. In fact, a substance emitted
inside a building may have more impact (particularly on health) than an outdoor emission, which is
much more diluted and causes less exposure because we spend around 90% of our time indoor.
But modelling the time varying indoor emissions, dilution according to air movements, occupants’
exposure and health risk is still a research topic, though a method is proposed [7]. Measuring
indoor release of substances is also difficult due to temporal variation, substance characteristics
and relationship with ventilation and air infiltration.
Local data is still missing in most countries, so that foreign LCI data is frequently used. But in this
case, adaptation is needed according to possible differences on e.g. the electricity production mix,
transport distance, origin of raw materials, waste treatment processes etc. Such data processing is
called “contextualization”. Adapting impact assessment to a local context is still a research topic.
6.4 Study of specific methodological aspects
There is at the moment no consensus on how to account for e.g. biogenic CO2 in LCA, as well as
allocation methods for co-products, modelling of recycling, elaboration of end of life scenarios for
different types of construction/renovation/demolition waste. Such aspects are being discussed
among the LCA community, and have implications in the building sector.

Plants convert carbon dioxide from air into cellulose and other substances by using direct sunlight
(photosynthesis), reducing the CO2 content of the atmosphere and hence to contributing to climate
change mitigation. The phenomena occurring in forests and the complex production processes
associated to timber products have been analysed in several studies. Two main approaches exist:
some authors do not account for biogenic CO2, arguing that the CO2 absorbed during
photosynthesis will sooner or later be released back into the atmosphere. Other models account
for a negative CO2 emission at the production stage and a release at the end of life depending on
the process (landfill, incineration with or without heat recovery, re-use etc.). A method is proposed
in the International Reference Life Cycle Data System (ILCD) handbook [2] in order to account for
CO2 storage during the life span of the material in a building: if x tons of CO2 are stored during n
years in a building, the accounted negative CO2 emission is n% of x (GWP100 being evaluated,
emissions or storage beyond 100 years are considered separately). Some authors account
negative CO2 emissions only for timber from certified forest (e.g. Forest Stewardship Council).
Several approaches are also possible to model co-products. The total impacts of the process can
be evaluated, but their allocation can be done according to the mass of each co-product, or their
value, or the system is expanded (which is recommended by ILCD). For instance, in the case of
waste incineration with energy recovery, the process is used for waste treatment, heat and possibly
electricity production. Allocation is needed to evaluate the impacts for each of these services,
which is useful for instance to perform an LCA of a building heated by such a source.
End of life is probably one of the most difficult stage to model, due to the large uncertainty on
processes that will occur in a far future (buildings being long lasting compared to most industrial
products). One approach is to consider, by precaution, the same waste treatment processes as
today. For instance if a material is incinerated today and not recycled, it may seem too optimistic to
assume that technical innovation will allow this product to be recycled in the future. One alternative
could be to use a probabilistic scenario.
Recycling generates an impact (noted Ir), and usually a supplementary transport related impact (It)
because the recycling facility is further than e.g. landfill (otherwise, It can be negative). On the
other hand it avoids the impacts corresponding to new fabrication (In) and to waste treatment (Iw).
Recycling should be promoted if the related impacts (Ir + It) are lower compared to the total impact
of new production from raw materials and waste treatment (In + Iw). The “avoided impact” by
recycling is then : In +Iw – Ir - It. In this case, good practice consists in:
- rewarding the use of recycled products at the construction phase,
- rewarding sorting waste and recycling at the end of life,
- avoiding double counting of the benefit of recycling.
The impact reduction depends on the recycling rates rf at the fabrication and re at end of life. There
exist different methods to model recycling in building LCA tools. According to the stock flow method,
the impact reduction is rf . (In – Ir) at the construction phase and re. (Iw – It) at the end of life.
The steel industry proposes a reduction of rf . (In – Ir) at the construction phase, (re-rf). (In-Ir) +
re.(Iw-It) at the end of life.
The avoided impact method evaluates an impact reduction of rf.(In+Iw-Ir-It)/2 at fabrication and
re.(In+Iw-Ir-It)/2 at end of life [12], the factor ½ being used to avoid double counting. The avoided
impact at the end of life is very uncertain, on the other hand it allows efforts towards “design for
dismantling” to be rewarded.
There exist as well different approaches to evaluate the impact of a system regarding resource
depletion. Simply adding material quantities does not account for the scarcity of each resource.
Some indicators are based upon the economically or technically available or ultimate reserve of
each raw material or fuel. Some account also for the extraction rate (abiotic depletion potential,
ADP, [6]), others are based upon the marginal increase of cost, or the “surplus energy”
(Ecoindicator 99, [5]): consuming a resource increases the cost or energy needed to extract this
resource because the reserve needing the lowest effort is extracted first.
One common knowledge gap in ADP and Ecoindicator 99 methods concerns uranium. This substance
is not included in the second indicator due to lack of data [15]. In the first indicator, ultimate

eserves are considered and the corresponding value is very large for uranium: 62.5 billion tons, to
be compared with 13 million tonnes probable reserves given by the U.S bureau of Mines. As a
result, the use of uranium has a negligible influence on the indicator value. In fact, a large part of
these ultimate reserves is very much diluted so that more energy would be needed to extract usable
uranium than the energy this uranium could provide. Therefore considering ultimate reserves
does not seem relevant in this case. If probable reserves would be used instead, the indicator
value would be much more sensitive to uranium consumption. This aspect is important in the building
sector, which consumes around 65% of the electricity produced in Europe, with around 40%
average contribution of nuclear plants. Specific research would therefore be needed to improve or
complement the existing resource indicators.
A primary energy demand indicator is evaluated in most of LCA tools (e.g. cumulated energy
demand) and, according to some guides and standards, split into renewable and non renewable
parts. But consuming solar electricity produced in the building itself or renewable electricity from
the grid may have different consequences on e.g. peak demand and grid management. Wood,
hydro-power and geothermal energy is limited: consuming wood in a building reduces the biomass
resource for others. On the other hand installing a solar collector on a roof does not reduce the
resource for others, so that adding solar and biomass energy consumption might not be relevant.
May be the right split is not between renewables and non renewables, but between limited and non
limited energy flows. In this logic, imported biomass, hydropower, geothermal and wind energy
would be accounted for but solar electricity or heat produced on site would not be considered
limited. Other indicators are related to resources (e.g. cumulative exergy demand [1], [14]), water
(considering potable, groundwater, rivers, oceans...), and ground (possibly accounting for ground
transformation).
Different indicators are also proposed for other environmental issues (e.g. global warming, toxicity,
eco-toxicity) and may correspond to mid-point or end-point evaluation: for instance a number of life
loss years is an end-point (or damage) indicator whereas a body weight subject to a certain dose
of pollutant is a mid-point indicator. Damage indicators require more sophisticated models [13], but
correspond more to corporate social responsibility approaches. The elaboration of a
comprehensive but not redundant set of indicators is finally needed.
Normalisation is useful to rank the contribution of a building on several impacts using the same
scale, allowing priorities for impact reduction to be identified (e.g. choosing the highest normalized
impact). Normalisation is based upon a reference value, generally per capita. This reference value
could correspond to a regional, national, European or world average, according to the purpose of
the study. Weighting factors are always normative/subjective, and reflect value assumptions: they
are not necessary in LCA but may be required by a client or political authority. In any case, LCIA
methods, possible normalisation and weighting, should be precisely documented so that the users
have a clear knowledge of the performed evaluation.
The different aspects listed above show that research is still needed in order to progress towards a
consensus and harmonization of these different approaches.
7. Elaboration of recommendations for different actors
7.1 Tool developers
It is first advised to integrate existing knowledge like ISO standards on LCA, future CEN standards
regarding applications in the building sector, guides elaborated by the International Reference Life
Cycle Data System (ILCD, [6]), European projects and literature.
Adapting the tools to professional practice may lead to give the choice between using default and
generic (or average) life cycle inventories at early design phases, then more specific EPDs to
compare products during detailed design. Limits and difficulties are addressed in the LORE-LCA
project regarding the consequential LCA approach, definition of the functional unit, system
boundaries, determination of cut off rule threshold, handling of far future and related uncertain

processes, performing sensitivity studies (e.g. regarding the considered life span of a building).
Interpretation is probably one of the steps requiring the most expertise. The tools should help the
users identifying the processes/materials and life cycle stages having a highest contribution in the
global impacts, e.g. using bar or pie charts, and contribution analysis techniques. Sensitivity studies
are also needed to check the robustness of the results in terms of assumptions (e.g. life span,
modelling choices etc.). Scenario analysis techniques can be used for this purpose. Uncertainty
analysis (e.g. using Monte Carlo simulation for stochastic uncertainty) would be also helpful, which
could constitute another research topic. Identifying limitations in the conclusions may be addressed
by presenting example case studies, showing that recommendations (e.g. design advice) can be
accompanied with statements limiting their scope (e.g. this recommendation is valid if the building
life span is longer than 50 years). The risk of misinterpretation could also be illustrated by examples
(e.g. over-interpreted comparison based upon insignificant impact differences).
As mentioned previously, LCA cannot be performed in the building sector with the same level of
detail as in the industry. In practice, a critical review process cannot be organised e.g. for the
design of one building. May be one solution is that such a review is organised once (or once a year)
for each Building LCA tool, in order to check the methodology, data and hypotheses. Organising a
users club with the possibility to cross review some studies, internet forums etc. could also be
relevant.
It is suggested to perform the benchmark study elaborated in the frame of the European thematic
network PRESCO (Practical Recommendations for Sustainable Construction, see http://www.etnpresco.net/generalinfo/index.html
[10]). Two case studies are described. The first one is a simple
concrete cube allowing a first verification of the life cycle calculation in a very simple case. The
second is a wooden house, also not too complex so that the risk of erroneous input is limited.
Several environmental indicators have been calculated using 8 tools developed in different
countries. The results can be used to compare new tools and identify possible errors.
7.2 Recommendations to users
The main application of LCA in the building sector is related to the design phase, allowing various
architectural and/or technical choices to be compared by design teams [16]. But LCA can also be
applied in earlier phases, e.g. to compare different possible building sites, or to select a project in
the frame of an architectural competition. In such a case, using default values is necessary for
unknown parameters, or predefined elements if the client has indicated some choices (e.g.
preference for wooden materials). All competitors should then use the same data. Different
simplified LCA tools exist, either spreadsheets or models combined with a graphical interface,
making possible to evaluate several projects proposed in a competition with a reasonable effort.
Projects having a different area will cause a difficulty to the jury: a larger building could be more
functional but generate more impacts, leading to a contradicting evaluation.
Elaborating a programme before the competition, including environmental targets, can also benefit
from LCA, which may even be used for policy making. In this case, due to the large scale of the
considered system, consequential LCA (CLCA) is generally more relevant than attributional LCA.
This has implications on the definition of the system boundaries because consequences on the
background system have to be accounted for. CLCA is more complex, and goes beyond the limits
of most present building LCA tools so that a large expertise is needed, e.g. to avoid double
counting of impacts, select appropriate life cycle data and define relevant scenarios to model the
complex cause and effect relationships between the studied system and the background system.
LCA can also be used as urban design aid [7], e.g. to compare different street and building
orientation, compactness, number of storeys etc. Higher use of solar energy for heating and
lighting may reduce the compactness of buildings, and increase the use of materials because of a
higher area of facade. A zero energy objective may lead to decrease the number of storeys, and
therefore to increase land use. Balancing building and transport related impacts may also
constitute promising applications. Target setting at a municipal level would also benefit of such life

cycle perspective. Like in the case of applying LCA for architectural competition, simplification is
needed, particularly when using excel based tools.
LCA is also used by manufacturers in order to elaborate data on building products in the form of
ISO-type III environmental declarations. Such data is based on a LCA study following the Product
Category Rules (PCR), which set the specific goal and scope of the LCA and the guidelines for
developing EPDs for one or more product categories (prescriptions for data collection, handling
and calculation rules). There exist presently EPD programmes in more than 10 countries. Some
methodological aspects are precised in standards, e.g. system boundaries in prEN 15 804,
reference service life in ISO 15686-1 and ISO 15686-8, cut off rules in ISO 21930, environmental
indicators in prEN 15804. All used data sources should be documented, specifying clearly their
uncertainty, integrity, representativeness (geographical, temporal, technological), coherence and
reproducibility. Using data from different EPD programmes to compare different materials is
generally not possible because the rules are defined nationally and they are in general not
harmonized.
Some work is performed to harmonize the application of LCA in the building and infrastructure
sectors, allowing e.g. the urban level to be addressed. Infrastructure includes a number of items,
such as roads, water supply, power grids, sewage systems, telecommunication, waste handling.
Each item involves many processes constituting a complex system. Various alternatives can be
proposed in each sector, e.g. road, rail, air and water transport, renewable or fossil energy systems,
landfill, incineration or recycling waste treatment etc. Beyond technical aspects, management
aspects may be also important (smart grid, intelligent transport systems...).
8. Conclusions and perspectives
Accounting for environmental issues in the building and urban sectors is presently based upon
rather subjective approaches. Yet the severity and planetary extent, long duration and possible
irreversibility of environmental impacts like global warming, nuclear risk, dispersion of toxic
substances, biodiversity loss and resource depletion, justifies more precise tools to be used in the
decision making process. LCA is presently the method incorporating the most knowledge, and is
increasingly considered in e.g. labelling or certification schemes. Knowledge gaps have still been
identified and harmonization work is needed regarding some methodological aspects like modelling
recycling and biogenic CO2. The LORE-LCA guidelines report is circulated among Building LCA
experts in order to get feedback regarding the identification of good practice and recommendations
to users and tool developers. Improving LCA tools and applying them in decision making would
help building actors to contribute in the reduction of environmental impacts in this sector, with a
possible extension to urban scale.
Acknowledgement
This research coordination action LORE-LCA has been funded by the European Commission
within the 7 th Framework Programme.
References
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[2] European Commission Joint Research Centre, International Reference Life Cycle Data System
(ILCD), General guide for life cycle assessment –detailed guidance, March 2010, jrc.ec.europa.eu.
[3] Finnveden, G., On the limitations of Life Cycle Assessment and Environmental Systems
Analysis Tools in General. International Journal of LCA 5 (4), (2000) 229-238.
[4] Finnveden, G., Hauschild, M., Ekvall, T., Guinée, J., Heijungs, R., Hellweg, S., Koehler, A.,
Pennington, D. W. and Suh, S. Recent developments in Life Cycle Assessment. Journal of
Environmental Management 91 (2009), 1–21

[5] Goedkoop M, Spriensma R. The Eco-indicator 99: a damage oriented method for life cycle
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