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Wednesday, 30 November 2016
Analysis of key environmental areas in the design and labelling of furniture products: Application of a screening approach based on a literature review of LCA studies
Published Date
doi:10.1016/j.spc.2016.07.002
Open Access, Creative Commons license
Author
Mauro Cordella a,,
Carme Hidalgo b,
aJoint Research Centre–Circular Economy and Industrial Leadership Unit, C/ Inca Garcilaso, 3, Edificio Expo, 41092 Seville, Spain
bLEITAT Technological Center, c. Innovació 2, 08225 Terrassa (Barcelona), Spain
Received 9 February 2016. Revised 5 July 2016. Accepted 5 July 2016. Available online 24 August 2016.
Highlights
Abstract
Environmental impacts of production and consumption can be controlled and reduced through instruments such as ecodesign and environmental labelling, which typically involve the analysis of complex product systems. The definition of more sustainable product options is not a trivial task and it can be complicated by factors such as the technical complexity and heterogeneity of products, available literature and impact assessment metrics used. The principles of systematic review and meta-analyses have been used to tailor an approach that can be used, to support eco-design and environmental labelling, for screening the environmental literature of products and the preliminary analysis of key environmental areas and improvement options. The approach has been applied to the furniture product group, for which 82 documents related to environmental aspects for different furniture products were collected.
The screening and analysis consisted of three steps:
1.selection of reference impact categories;
2. screening of studies according to a qualitative–quantitative framework;
3. analysis of selected studies and extraction of relevant information.
Five impact categories have been analysed: Acidification, Climate Change, Eutrophication, Ozone Depletion, Photochemical Ozone Formation. Analysis of documents covering a broad group of furniture products has allowed the understanding of critical areas, improvement options and technical aspects on which to concentrate investigation efforts in order to reduce the life cycle impacts.
The approach can, in general, be adapted to any products for addressing the further development and implementation of measures with which to promote more sustainable options (e.g., ecodesign, environmental labelling, green public procurement criteria).
Keywords
Environmental design and labelling
Furniture products
Key environmental areas
Life Cycle Assessment
Screening approach
Systematic review
1 Introduction
Environmental impacts of products can be controlled by improving the eco-efficiency of the product life cycle, which could be pursued for instance through the implementation of instruments such as eco-design and Type I environmental labels (Hauschild et al., 2005). Eco-design activities can support the reduction of the life cycle impacts of products through the consideration of environmental aspects during their conceptual stage (Anastas and Zimmerman, 2003). Type I environmental labels (International Organization for Standardization, 1999) are instead voluntary programmes aimed at identifying and marking environmentally superior products according to criteria developed on the basis of life cycle considerations. This type of label can thus serve as a pull mechanism for driving the market towards more sustainable product options.
Without considering behavioural aspects related to the interaction between products and consumers, the effectiveness of eco-design activities and product labelling depends on the early and coherent definition of key environmental areas on which to concentrate further investigation efforts for achieving relevant and tangible gains. In this sense, a core role is played by the Life Cycle Assessment (LCA) methodology (International Organization for Standardization, 2006a and International Organization for Standardization, 2006b), which is the standard approach to follow for assessing the environmental impacts of products and identifying life cycle hotspots and improvement options. Moreover, a complementary product-oriented analysis may be necessary to handle legislative, techno-economic and environmental aspects of concern that are not conventionally covered, or fully integrated into the LCA (as can be the case for issues related to product quality, inherent safety of materials, indoor air pollution and, for some products, noise emissions).
LCA studies and other material available in the literature can represent important sources of information for addressing the assessment and improvement of the sustainability of products. However, the definition of more sustainable product options is not a trivial task and it can be complicated by factors such as: technical complexity and heterogeneity of products, availability of studies, and impact assessment metrics used. A preliminary and tailored screening of the literature is thus needed to focus on documents with which to build coherent outcomes and understand whether there are information gaps to be filled. This can be achieved through systematic reviews and meta-analyses (Brandão et al., 2012, Lifset, 2012, Zamagni et al., 2012 and Zumsteg et al., 2012) and can be particularly useful when the scope of the analysis is broad and/or the technical and scientific production is significant, as is the case for the furniture product group (see as an example the list of documents available in Online Resource 1, Appendix A).
Systematic literature reviews are analyses of studies selected on the basis of predefined criteria and which aim to extract relevant information with which to answer specific questions. Results can be also combined quantitatively through meta-analyses (Ressing et al., 2009). Systematic reviews and meta-analyses are widely used in disciplines such as ecology, epidemiology, medicine, psychology or software engineering, where standardised frameworks and protocols have also been proposed (Chambers and Wilson, 2012, Lifset, 2012, Ressing et al., 2009, Thompson et al., 2012 and Zumsteg et al., 2012). Utilisation in the field of LCA has begun in the last few years, both at a practical and methodological level (see for instance: Price and Kendall, 2012, Wolf et al., 2015 and Zamagni et al., 2012), although no widely recognised guidelines are available (Brandão et al., 2012, Lifset, 2012 and Zumsteg et al., 2012). Because of this, Zumsteg et al. (2012) proposes general guidance on how to conduct a systematic review of LCA studies. Recommendations on aspects to consider when evaluating a LCA study can also be found in European Commission (2013).
The principles of systematic review and meta-analyses have been used in this paper to tailor an approach that can be used to support the implementation of eco-design activities and environmental labelling of furniture products in Europe (although it could potentially be extended and adapted to other products and contexts) for the following:
1.
The screening of the environmental literature on the products analysed.
2.
The preliminary analysis of key environmental areas and improvement options.
Considering that this is an initial step for the implementation of the instruments above (further in-depth analyses and stakeholder consultations are necessary to investigate technical, economic and environmental aspects), the approach was streamlined by:
1.
keeping the goals and scope of the review process and selection criteria focused on specific aspects and practical objectives of the intended application (rather than more methodological issues);
2.
defining a simple and flexible qualitative–quantitative evaluation framework which can be easy to apply and allow the efficient extraction of preliminary information from the literature about environmental impacts and critical aspects of products.
On the other hand, the approach itself is not a stand-alone tool as it has to be coupled with further analyses and information and does not, on its own, allow a full and robust quantification of the environmental profile of products (for which a statistically representative set of data would be needed), or the exploration of more methodological issues and developments. However, these and other aspects could be taken into account in further updates of the approach.
2 The furniture product group
Furniture is a product group of great interest for eco-design activities and product labelling (see for instance: EU Ecolabel, 2014 and The International EPD® System, 2014a). The definition of furniture covers a broad set of products used daily in both domestic and non-domestic spaces for functions such as storage, hanging, supporting, lying, sitting, working and eating. Typical products are chairs, desks and tables, cupboards and wardrobes, kitchens, bed structures and sofas, which can all be made of different materials (e.g. wood, metals, plastics, glass, textiles, stone) and placed on the market in a variety of designs (Postell, 2012). Apart from the heterogeneity in terms of product types, designs and materials used, furniture is also characterised by a broad and complex value chain, as depicted in Fig. 1 for a generic product. From a system perspective, the product’s life cycle can be split into three main blocks: upstream activities (i.e. production, supply and processing of materials and components), core activities (i.e. product manufacturing, assembly, finishing, packing and storage); and downstream activities (i.e. product distribution, retail, use, maintenance and end of life).
Fig. 1. Streamlined value chain of a generic furniture product.
3 Materials and methods
The first stage of the screening approach consisted of collecting documents which could potentially allow the identification of key environmental areas and improvement options for the furniture product groups and with which to address potential activities on eco-design and environmental labelling (i.e. the research question).
The search of documents was performed in April 2013 through search engines and databases of peer-reviewed literature (Google Scholar, 2016, ScienceDirect, 2016and Scopus, 2016). The search was based on combinations of key words such as LCA, environment, sustainability and specific types and materials of furniture products (e.g. office furniture products, wooden furniture). Additional documents were gathered from webpages of EPD schemes (The International EPD® System, 2014a and The Norwegian EPD Foundation, 2016) and through a direct call for contributions from experts in LCAs and furniture products (e.g. by mailing the LCA discussion list managed by Pré).
This resulted in a sample of 82 documents dealing with environmental issues related to different types of furniture (see the list available in Online Resource 1, Appendix A), which includes scientific papers, environmental product declarations (EPDs) and other technical reports.
The second stage consisted of screening and analysing the collected documents, which was performed on three steps:
1.
selection of reference impact categories;
2.
screening of studies according to a qualitative–quantitative framework;
3.
analysis of selected studies and extraction of relevant information.
3.1 Selection of reference impact categories
The environmental analysis of product groups can be complicated both by the broadness and heterogeneity of the scope and also by the variety of impact assessment approaches followed in different studies, as is the case for furniture.
General recommendations on impact categories to cover in LCA studies and related assessment methods are, for instance, provided in the Product Environmental Footprint (PEF) Guide (European Commission, 2013). The document proposes 14 environmental impact categories and related indicators, building on the information produced in the ILCD Handbook (European Commission’s Joint Research Centre, 2011), where existing impact assessment methods were reviewed, evaluated and classified. The ILCD Handbook indicates that, at the state of the art, “recommended and satisfactory” assessment methods exist for the Climate Change, Ozone Depletion, Particulate Matter / Respiratory Inorganics impact categories, with further research and development efforts needed for other methods.
The greater the number of impact categories analysed, the more comprehensive the description of the environmental profile of products. Nevertheless, the availability of reliable information tends to decrease and trade-offs among different impact categories tend to increase as the numbers of impact categories and indicators increase. Considering that the goals of the approach presented is to identify key environmental areas and improvement options in the life cycle of the products analysed, the screening was streamlined by selecting a sample of key impact categories which could be considered of relevance for the product group under analysis and for which satisfactory and reliable information can be found. A narrow set of impact categories can be functional for the definition of key environmental areas and improvement options, as indicated in ADEME (2010) and Cordella et al. (2015) for example.
Five impact categories were selected for testing the screening approach on furniture:
1.
Acidification;
2.
Climate Change;
3.
Eutrophication;
4.
Ozone Depletion;
5.
Photochemical Ozone Formation.
The quantification of impacts for the categories Acidification, Climate Change and Eutrophication generally appears compulsory in the PCRs consulted for furniture and supported by the indications provided in (ADEME, 2010). Potential environmental impacts in these categories are significantly proportional to the consumption of energy, as reported in Askham et al. (2012) and Huijbregts et al. (2006).
Ozone Depletion and Photochemical Ozone Formation are two impact categories to quantify within the International and the Norwegian EPD Systems. In particular, the consideration of Photochemical Ozone Formation may be relevant for furniture because of the use of solvents (ADEME, 2010).
Although resource scarcity is considered as an important parameter to take into account, an impact assessment category on resource depletion was not included when the screening approach was applied. Significant differences exist between methods used to assess impacts due to depletion of resources which call for further improvement and consensus (Klinglmair et al., 2014). In addition, depletion of resources and production of waste are often reported in the available literature for furniture as material and energy flows. It should however be noted that the selected impact assessment metric allows the analysis, at least partially, of the environmental importance of materials and waste over the life cycle as impacts due to consumption of resources, as well as to production of waste, are analysed with respect to five impact categories. For a product group like furniture it is expected that the consideration of an additional impact category specifically handling depletion of resources would confirm the importance of materials as a key environmental area. In contrast, a more detailed assessment of depletion of resources may be more relevant for electronic products, as may be for instance the case for computers, TVs and washing machines.
With respect to toxicity parameters, this is recognised as an important issue for protecting human health and the environment. This impact category is not covered in the PCR documents consulted for furniture, which typically ask for the collection of information on use and emission of chemicals. Moreover, no “recommended and satisfactory” methods exist for this impact category (European Commission’s Joint Research Centre, 2011), with further methodological improvements and investigation at the substance level needed to build a comprehensive database. Efforts in this area are ongoing to converge towards a “scientific consensus model” (USEtox, 2014). Positive effects in this area could in the meantime be achieved through a product-oriented approach carefully investigating how to reduce the inherent hazards of products, components and substances (Cordella et al., 2009 and European Union, 2010). Some preliminary indications on hazardous substances of potential concern were reported when screening the studies.
3.2 Screening of studies according to a qualitative–quantitative framework
As is typical in systematic reviews (Price and Kendall, 2012 and Zumsteg et al., 2012), criteria were set in order to establish a qualitative–quantitative framework for the identification of documents of relevance for the analysis. Criteria were adapted from the recommendations provided by European Commission (2013) on aspects to consider when evaluating a LCA study.
Criteria, presented in detail in Table 1, cover aspects related to: (1) scope of the study; (2) data quality and representativeness; (3) impact assessment metric; (4) relevance of findings; (5) robustness of the study; (6) presence of an independent review process.
Table 1. Criteria considered for the screening approach.
Information
Inclusion criteria
Evaluation criteria and scoring
1
Scope of the study
–Coherent scope definition for the analysis
5 = Coherent LCA for a broad group of products of interest
1. Type of study (e.g. attributional/consequential LCA, fulfilment of ISO 14040/PAS 2050/PCRs/PEF/…)
–Key assumptions of the study fulfilling ISO 14040 standards
3 = Coherent LCA for one product OR Streamlined LCA for more products of interest
2. Product system(s) analysed
1 = Streamlined LCA for one product of interest
3, Functional unit
4. System boundaries (stages and process cut-off)
5. Main modelling assumptions (e.g. allocation)
2
Data quality and representativeness
–
(I) Average data representativeness to be evaluated for each stage:
1. Materials (including packaging)
5 = High quality data:
2. Manufacture
–Representative from a geographical and technical point of view for average conditions of relevance within the context analysed
3. Distribution
–Up-to-date, mainly collected on site for foreground processes (e.g. primary data collected less than 3–5 years ago)
4. Use phase
3 = Average quality data:
5. End of Life
–Representative from a geographical and technical point of view for average conditions of relevance within the context analysed
–Recent (e.g. collected less than 5 years ago)
1 = Low quality data:
–Outdated (e.g. collected more than 5–10 years ago) or of less interest from a geographical and technical point of view
(II) The overall score for data is the average of the points assigned to each single stage
3
Impact assessment metric
–At least one impact category of reference is characterised through methods which are classified as at least “C” according to the ILCD Handbook
5 = Complete coverage of the reference impact categories and satisfactory quality of impact assessment methods (classified as “A” or “B” according to the ILCD Handbook)
3 = At least one impact category of reference is characterised through methods classified as “A” or “B” according to the ILCD Handbook
1 = At least one impact category of reference is characterised through methods classified as at least “C” according to the ILCD Handbook.
4
Relevance of findings
–Findings of the study are relevant for the identification of key environmental areas and improvement options for the product system analysed
5 = Findings of the study are very relevant for the achievement of the goals of the analysis
3 = Findings of the study are partially relevant for the achievement of the goals of the analysis
1 = Findings of the study have minor relevance for the achievement of the goals of the analysis
5
Robustness of the study
–
5 = Main assumptions and quality of the study are considered good and sensitivity analysis is performed to manage primary sources of uncertainty and variability
3 = Main assumptions and quality of the study are considered good
1 = Quality of the study can be considered acceptable but some potential weaknesses are detected which require critical interpretation
6
Presence of an independent review process
–
5 = Independent third party review (e.g. paper)
3 = Other third party review (e.g. certification)
1 = No review
A sample of 82 documents of potential relevance for different types of furniture was considered for the screening (see Online Resource 1, Appendix A). The evaluation was carried out in two steps:
(I)
Verification of the fulfilment of the inclusion criteria:
•
coherence of the scope and adherence to the ISO 14040/4 standards;
•
at least one of the reference impact categories identified in the previous step is characterised through methods which are classified as at least “C” according to the “science-based criteria overall evaluation” carried out in (European Commission’s Joint Research Centre, 2011);
•
relevance of the findings of the study for identifying the key environmental areas and improvement options of the product system analysed.
(II)
Qualitative–quantitative evaluation of the LCA studies that pass the first level of screening, on the basis of the six criteria reported at the beginning of this section (scope of the study; data quality and representativeness; impact assessment metric; relevance of findings; robustness of the study; presence of an independent review process).
For each parameter a score from 1 to 5 was assigned, as described in Table 1, on the basis of the qualitative evaluation of the studies. Each study obtained an overall score from 1 to 30. Studies were further analysed when the total score was 15 or above. The use of scoring in the system review for the selection/analysis of documents does not appear a common practice in LCA (see, for instance Price and Kendall, 2012). Semi-quantitative indications for data-quality assessment and rating are, for instance, provided by European Commission (2013). However, a more practical and broader scoring system was considered more suitable for this application.
Documents that did not pass the screening were tracked if they were considered useful for complementing the LCA information gathered through the review with information on other environmental issues of concern which may merit further investigation. In the case of furniture, this was the case, for instance, for the analysis of hazardous substances potentially present in products and for the sourcing of wood from sustainable forest management (FAO, 2014).
New studies should be sought, or ad-hoc investigations conducted, in the event that the basis of the information produced is not considered satisfactory within the context of the analysis.
3.3 Analysis of selected studies
Selected LCAs that passed the screening were analysed to understand the range of the information available from these documents and to further identify key environmental areas for furniture and possible options for improving the environmental profile of this product group in the European context.
A simple meta-analysis was also carried out to obtain rough indications of the contributions of single life cycle stages to total impacts, both as averages and variations of such contributions. This was done by processing the information on the breakdown of total impacts reported for 72 case studies. The life cycle of the products was divided into five subsystems: production and supply of materials (P1), product manufacturing (P2), distribution (P3), use and maintenance (P4) and end of life (P5).
An element complicating this contribution analysis is that the assumptions and aggregation level with which results are calculated can vary from source to source. To overcome this obstacle, the sum of P1 and P2, which were found to be the most frequently quantified contributions, was taken as a reference basis for the comparison of different subsystems. Contributions from the five subsystems have thus been expressed in relative terms as a percentage of the sum of P1 and P2, which is to say that P1+P2=100%.
These LCA studies obtained a score of 15 or above and were thus considered to be qualitatively satisfactory and focused on the achievement of the practical objectives of the research question (“identifying key environmental areas and improvement options for the furniture product groups and with which to address potential activities on eco-design and environmental labelling”).
4.1 Goal and scope of selected studies and EPDs
The identification of hotspots along the product life cycle was found to be a typical element of the analysis for the selected studies. In addition, some studies also addressed the comparison of different design options (see for instance: ADEME, 2010, González-García et al., 2012 and IHOBE, 2010). The following furniture types are covered:
Selected LCA studies and EPDs generally refer to assembled products. The scope is broad in terms of products and it can be considered representative of indoor furniture. Complementary information on specific issues of relevance for outdoor furniture, such as wood treatment, should be sought separately (see for instance: Online Resource 1, Appendix A).
The assessed products are composed of a variety of materials. Generally, wood is the main material used in furniture. Wood materials can consist of wood boards or panels. Almost all products have some components made of metals, mainly aluminium and steel. The relative weight of metals and plastics become more significant for non-domestic applications. Typical plastic components are polypropylene (PP) and polystyrene (PS). Other materials can also be important for some products, such as glass for cabinets and bookshelves or upholstering textiles for seats and sofas. Some studies analysed issues related to forestry operations and coatings of wood and recycling of materials (Distretto del Mobile di Livenza, 2010, González-García et al., 2012, Mitchell and Stevens, 2009 and Spitzley et al., 2006).
Making reference to the scheme reported in Fig. 1, in terms of data sources process data for core activities were in most cases gathered from manufacturers while information on upstream and downstream activities were usually modelled based on information from suppliers, statistics and Life Cycle Inventory (LCI) databases. Production and supply of components was normally considered an upstream activity. Nevertheless, in some cases this was integrated with the product manufacturing stage. Similarly, downstream activities were sometimes modelled as aggregated processes. It is apparent that the non-harmonised definitions of system boundaries and subsystems are factors which complicate the comparison of results obtained in different studies.
With respect to the functional unit of studies, this should ideally relate to the function, quality, design and lifespan of products. However, because of the diversity in the type of products and applications, three main approaches were found to be generally applied:
The assessment refers to one unit of product and to the average expected duration of use (IHOBE, 2010). This approach usually appeared to be followed in studies related to the assessment of one or more product design options, including EPDs.
In the last two approaches there is an overlap between the functional unit and reference flow. The existence of different approaches used to define the functional unit makes the analysis of the outcomes from different studies more critical, especially when the lifespan of products is not taken into account. Function and lifetime should be essential elements to consider in the assessment of products.
4.2 Impact assessment methods used in selected studies of EPDs
Reference impact categories presented in Section 3.1 are fully covered in the LCA studies which passed the screening and by the analysed EPDs, as shown in Table 2:
Acidification Potential (AP) and Ozone Depletion Potential (ODP) were generally characterised according to versions of the CML method (Guinée et al., 2002), which is classified as “B” according to the “science-based criteria overall evaluation” provided in European Commission’s Joint Research Centre (2011). Exceptions are represented by Spitzley et al. (2006) which used the TRACI method, Bare et al. (2006)which characterised AP (classification “E”) and by Distretto del Mobile di Livenza (2010) which based the calculation of ODP on semi-empirical and timedependent characterisation factors developed by Solomon and Albritton (1992) (not classified) were assessed. Eutrophication Potential (EP) and Photochemical Ozone Formation Potential (POFP) were characterised according to versions of the CML method (classification “B” for both) (Guinée et al., 2002). Climate Change has been characterised for all studies as Global Warming Potential (GWP) according to methods classified as “A”: CML (Guinée et al., 2002), IPCC 2007 (Intergovernmental Panel on Climate Change, 2007), and TRACI (Bare et al., 2006).
Table 2. Impact categories considered in selected LCA studies and EPDs and related impact assessment methods.
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