Environmental profile of ceramic tiles and their potential for improvement

Accepted Manuscript Environmental profile of ceramic tiles and their potential for improvement Marisa Isabel Almeida, Ana Cláudia Dias, Martha Demertzi, Luís Arroja PII:

S0959-6526(16)30419-X

DOI:

10.1016/j.jclepro.2016.04.131

Reference:

JCLP 7156

To appear in:

Journal of Cleaner Production

Received Date: 10 October 2015 Revised Date:

24 April 2016

Accepted Date: 26 April 2016

Please cite this article as: Almeida MI, Dias AC, Demertzi M, Arroja L, Environmental profile of ceramic tiles and their potential for improvement, Journal of Cleaner Production (2016), doi: 10.1016/ j.jclepro.2016.04.131. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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Environmental profile of ceramic tiles and their potential for

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improvement

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Marisa Isabel Almeida a, b *, Ana Cláudia Diasa, c, Martha Demertzia, Luís Arrojaa, c

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Portugal

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b

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Coimbra, Portugal

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c

Department of Environment and Planning, University of Aveiro, 3810-193, Aveiro,

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Technological Center of Ceramics and Glass - Rua Coronel Veiga Simão, 3025-307,

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Center of Environmental and Marine Studies (CESAM), 3810-193, Aveiro, Portugal

*Corresponding author: E-mail address: [email protected]. Tel.: +351 239 499 200

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Abstract

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This study evaluates the environmental profile of ceramic tiles produced in Portugal

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based on a cradle-to-grave Life Cycle Assessment (LCA), including mining,

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manufacturing, construction, use and final disposal. The main hotspots are identified

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and improvement actions are suggested in order to reduce the environmental impacts.

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According to the results, the major hotspot is the production stage (cradle-to-gate), for

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all categories except ecotoxicity and land use. Within this stage, the processes that have

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the greatest impact are the following: onsite activities (especially the burning of natural

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gas for the tile manufacturing process), transport, electricity production and production

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of natural gas. Among the improvement actions analyzed, the most efficient measure

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studied to reduce the environmental impacts was a combination of actions to reduce fuel

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consumption (best available technique), electricity and raw material transport distance,

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although the economic sustainability could be a critical issue. This work also identified

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the main environmental impact categories that can be used to define ceramic tiles

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environmental profile, thus encouraging an update of environmental communication

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tools based on LCA.

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Keywords: Ceramic tiles; Cradle-to-grave; Environmental impact; Hot spot;

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Improvement measures; Life Cycle Assessment (LCA)

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1. Introduction

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The construction sector has a great positive impact on society and the economy, being

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responsible for 30% of the industrial employment in the European Union (EU), and

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contributing about 10.4% to the gross domestic product of the EU (European

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Commission, 2010a). At the same time, however, the construction sector is considered

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the highest energy consumer in EU, accounting for almost 40% of the total energy

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consumption and contributing almost 36% to the EU’s total greenhouse gas (GHG)

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emissions (European Commission, 2011a). Apart from emissions, buildings and the

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built environment store a large amount of material as well. Due to the important impacts

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of the construction sector on the environment, there are increased concerns about, and

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orientations towards, more sustainable construction processes, with a special focus on

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resource usage efficiency (Frej, 2005; Ortiza, 2009; Rademaekers et al., 2011), as well

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as on the use of more sustainable materials with lower environmental impact over their

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entire life cycle.

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The ceramic materials traditionally used in the construction sector are inorganic, non-

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metallic materials that include minerals and rocks. Their main characteristic is the fact

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that they are the result of a natural raw material mixture that contains silica, at least one

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ACCEPTED MANUSCRIPT argillaceous mineral, and usually alkaline oxides. However, depending on the mixture,

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the final ceramic products can present several differences, such as in porosity, color,

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presence of enamel, etc. (Boch and Niepce, 2007), along with having high durability

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and performance. Furthermore, the ceramic industrial sector continues to develop,

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attempting to reduce costs, improve the reproducibility of products and compete with

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other markets’ products by developing new equipment and having better knowledge of

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ceramic properties and evolution (Wuppertal Institute, 2009).

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Portugal is a country with a long tradition in ceramics, both in production and

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consumption, and is ranked as one of the top European manufacturers of ceramic

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products (Eurostat, 2014) due to the high quality of raw materials. The Portuguese

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ceramic industry produces a variety of products adapted to building works, such as

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bricks, covering materials, flooring tiles, etc. The ceramic sector in Portugal consists of

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five sub-sectors: (1) decorative ceramics, (2) sanitary ware, (3) insulators and technical

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ceramics, (4) floor and wall tiles and (5) structural ceramics (APICER, 2009). Wall and

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floor ceramic tiles represent 22% and 32% of the production value of the ceramic

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industry in Portugal and in Europe, respectively, and this subsector constitutes the

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largest sector in terms of turnover among European ceramic industries, with total sales

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in 2009 estimated at around 9 billion euros (ECIA, 2012). In Portugal, total sales of wall

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and floor ceramic tiles in 2013 accounted for around 332 million euros (INE, 2014),

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corresponding to about 50 millions of m2 produced. Portugal is also the fourth largest

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producer in Europe and the fifth largest world exporter of floor and wall tiles, after

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China, Italy, Germany and Spain.

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Assessing the environmental impacts of the different types of ceramic products has

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become crucial to improving the environmental performance of this sector. Such

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assessment can be achieved through Life Cycle Assessment (LCA) studies based on

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ACCEPTED MANUSCRIPT ISO 14040 and ISO 14044 standards (ISO, 2006a, 2006b), applied to the different

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stages of a product's life cycle. Many LCA studies of building materials can be found in

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literature, such as for wood (Nebel et al., 2006; Werner and Richter, 2007), brick

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(Almeida et al., 2015; Dompros, 2007; Koroneos and Rouwette, 2010) and cement

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(Loijos et al., 2013; Zhao et al., 2013). Some comparative LCA studies on building

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materials including ceramics have also been published, namely regarding different

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alternatives of building elements and their performance in the building (Asif et al.,

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2007; Bribián et al., 2011; Calkins, 2003). In LCA studies done on ceramic tiles,

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Nicoletti et al. (2002) compares ceramic tiles with marble; Almeida et al. (2013)

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presented LCA data quantifying the performance of a floor tile in an Environmental

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Product Declaration (EPD) according to EN15804; Benveniste et al. (2011) performed

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LCA in order to define product category rules for floor and wall tiles with the

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participation of more than 50 Spanish companies; Bovea et al. (2007, 2010) assessed

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environmental performance and improvement proposals for Spanish ceramic tiles;

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Ibáñez-Forés et al. (2011, 2013) assessed the sustainability of Best Available

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Techniques (BAT) for Spanish ceramic tiles; Fullana and Palmer (2011) assessed

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Spanish ceramic floor and wall tiles; and Quinteiro et al. (2014) assessed the carbon

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footprint of several ceramic materials, including floor and wall tiles.

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The novelty of the present work is that it evaluates new impact categories and their

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relevance, as well as new improvement actions and their relation to several European

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instruments (legal and voluntary). In this context, the objective of the present study is to

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assess the whole life cycle of ceramic tiles produced in Portugal, using LCA to identify

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the stages and processes having the greatest environmental impacts. The end purpose is

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to develop actions to reduce those impacts, including the effectiveness of some

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European instruments. This work also intends to study and highlight the main

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ACCEPTED MANUSCRIPT environmental impact categories that can be used to define the environmental profile of

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ceramic tiles and their variability for the same production technology, fuel and group

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classification.

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2. Methodology

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This study applies an LCA methodology, taking into account the ISO 14040 and ISO

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14044 standards (ISO, 2006a, 2006b), to four average ceramic tiles produced by four

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different manufacturers located in the central region of Portugal and used in the building

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sector across the word. This will be done using a cradle-to-grave approach that includes

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all stages of the life cycle, from the mining process to transport to the manufacturer, the

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manufacturing process, transport of the ceramic tile to the construction site, use and

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final disposal.

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2.1 Product description

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The ceramic tiles considered in this study belong to the BIa/b Group, in accordance with

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the European standard EN 14411 (CEN, 2012). Moreover, they fulfill the requirements

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of the Construction Products Regulation (European Commission, 2011b) in terms of

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mechanical resistance and stability, safety in case of fire, hygiene and health, safety in

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use, protection against noise, energy economy and heat retention.

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The data in this study represent specific average data from each manufacturing plant

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and company, identified as Tile 1, Tile 2, Tile 3 and Tile 4. These case studies are

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representative of ceramic tiles produced in Portugal, and also around the world, in terms

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of installed capacity, kiln type and dimensions (single fired in roller kilns), technology

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used for conformation (dry-pressing technique) and fuel used (natural gas). Moreover, it

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should be noted that the mixtures of ceramic raw materials are distinct for each average

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tile, as is the glazing (see Table 1). Tiles 1 and 3 are glazed tiles, Tile 2 is unglazed, and

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ACCEPTED MANUSCRIPT Tile 4 is both glazed and unglazed. Tile 2 and Tile 4 are porcelain stoneware, while Tile

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1 and Tile 3 are porcelain glazed tiles.

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2.2 Functional unit and system boundaries

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The functional unit selected for this study is 1 m2 of ceramic tile with a lifespan of 50

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years, ready to be sold for use as floor covering in a residential building interior. This

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functional unit is in line with the reference European standard EN 14411 (CEN, 2012)

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and previous studies in this field mentioned in the Introduction, with the exception of

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lifetime, which varies from 20 to 50 years. However, EN14411 also points out 50 years.

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Due to the cradle-to-grave LCA approach, the system boundary includes the entire life

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cycle of the ceramic tile.

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Figure 1 presents the entire life cycle system divided into five subsystems. Subsystem 1

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is a cradle-to-gate LCA approach and includes the extraction and production of raw and

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ancillary materials (clay, kaolin, feldspar, glazing materials, etc.), fuel production

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(natural gas and diesel), electricity production, packaging production (carton, packing

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film and pallets), their transport to the manufacturer, and the ceramic tile manufacturing

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process (on-site emissions). The manufacturing process includes several steps: clay

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preparation (processing of a plastic clay body), pressing (forming technique), drying

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(moisture removal from the formed ceramic tiles), glazing (layer or coating of a vitreous

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substance to color, decorate, strengthen or waterproof the ceramic tiles), firing (passing

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of the ceramic tiles through kilns for intense heating at around 1200oC to add strength

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and the desired porosity), subsequent surface treatment (includes grinding and polishing

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of the ceramic tiles), packaging, and storage of the ready-to-sell ceramic tile. It also

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includes maintenance operations and wastewater treatment plants. All factories use

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single-fired technology with natural gas as the fuel. Additionally, they have applied

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available techniques to reduce gaseous emissions from the firing operation; these

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gas cleaning with a filter (Tile 1), the latter being the best available technique (BAT).

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Subsystem 2 includes the transport of the ceramic tiles to distribution centers and their

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subsequent transport to the construction site. In this case, a transport scenario of 1000

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km by road was applied for the total distance, considering an average distance to

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France, since it is a main destination for Portuguese ceramic tiles. Subsystem 3 includes

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the installation of the ceramic tiles in the building using mortar. Subsystem 4 includes

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the use of the ceramic tiles after their installation and the cleaning/maintenance

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operations with the use of detergent (soap) once per week. Subsystem 5 includes the

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final disposal of the ceramic tiles at the end of their life cycle.

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A cut-off rule of 0.5% in mass of input and output flows in relation to the mass of tiles

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was applied, allowing the identification of materials that were excluded from the system

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boundaries.

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The construction of industrial infrastructures, manufacture of equipment and machinery,

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and the burdens of infrastructures (vehicle manufacturing, road maintenance) associated

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with the transportation of pre-products and raw materials were also excluded. The LCA

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was drawn up for Portugal as a reference area.

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2.3 Inventory data

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The data collected on the production of the representative ceramic tiles cover one year

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and represent averaged data (reference year 2012). The data were obtained directly from

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the four factories under study through questionnaires, audits or direct measurements

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made along the supply chain, from mining processes to manufacturing. The

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transportation distances and types of transport between raw material extraction sites and

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manufacturing sites were obtained from the industry and include the extraction site

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ACCEPTED MANUSCRIPT locations, routes and types of transport used (lorry and ship). The waste reused

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internally (inert materials such as ceramic waste before thermal processing, dust, dry

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broken ware) was modelled as closed-loop recycling. The adhesive mortar production

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was modeled according to a recipe from a national producer.

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When it was not possible to obtain primary data, the last version of Ecoinvent database

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(Ecoinvent, 2012; Hischier, 2007) was used (mainly for background data). The

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secondary data include the production of electricity, fuels, steel, wood pallets,

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lubricating oil, detergent (use stage), glazes, kaolin, magnesite, packaging material, and

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maintenance materials, as well as the emission factors for transport and final disposal.

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Table 1 presents the inputs and outputs of the manufacturing process for 1 m2 of the

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ceramic tiles considered.

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Table 2 presents the data concerning natural gas consumption during the manufacturing

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process, namely for the unit processes of clay atomization, drying and firing. It should

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be noted that firing demands the highest consumption (45 to 50%), followed by the clay

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atomization (30 to 35%) and drying processes (15 to 25%).

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2.4 Life cycle impact assessment

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Selection of the impact categories was based on the following criteria, which reflect the

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relevance of environmental issues regarding ceramic tiles:

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studies on ceramic materials (Almeida et al., 2013, 2015; Benveniste et al, 2011;

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Ibáñez-Forés et al., 2011, 2013) including also the suggestions for future studies, like

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resource use and land use (Bovea et al., 2007, 2010);

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Inventory data availability and its relation to impact categories; Environmental impact categories’ relevance, as identified by previous LCA

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Impact categories defined in EN15804+A1 (CEN, 2013) for construction

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products and services, in which ceramic tiles are included;

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recommended methods (EC-JRC, 2011), for categories other than those defined in

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EN15804 that indicates the CML method (Guinée, 2001).

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Robustness of the method and stakeholder acceptance, namely the ILCD

According to previous studies and the criteria outlined above, the extraction of raw

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materials and the combustion of fossil fuels in the production ceramics have impacts

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related to global warming (GW), acidification (A), eutrophication (E), photochemical

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oxidation formation (POF), and abiotic depletion fossils (ADf) and elements (ADe);

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these impact categories are mentioned in EN15804+A1 (CEN, 2013), which also

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includes ozone layer depletion (OD).

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In addition to these categories, and in order to achieve a more complete environmental

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profile and to assess their relevance for ceramic tiles, the following impact categories

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were also analyzed: human toxicity (HT), including cancer and non-cancer, ecotoxicity

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(ET), particulate matter (PM), land use (LU) and water resource depletion (WD).

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Table 3 presents the methods and references used in the LCA assessment for the

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different impact categories.

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3. Results and discussion

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Table 4 summarizes the environmental impact results (using a cradle-to-grave approach)

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of the four cases of average ceramic tiles. The values within each impact category have

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the same order of magnitude, although Tile 1 displayed the best environmental

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performance in all impact categories, except for ozone depletion and land use, for which

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Tile 3 performed better. Tile 4 presented the worst environmental performance in all

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ACCEPTED MANUSCRIPT impact categories, except for human toxicity (for which Tile 3 was the worst).

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Variability was seen within the same impact categories (from 5 to 47%, except for ADe,

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which reached 179%). This is important, especially when doing studies covering sector

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averages, like sectorial EPD. These differences in environmental impacts of the average

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tiles could be explained by the different raw material mixtures and the resulting

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operating conditions needed for each manufacturing process, particularly the maximum

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temperature of the firing process. In fact, firing is the most influential step of the

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manufacturing process for ceramic tiles due to the high temperatures (1100oC –

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1225oC), high amounts of natural gas are required (Table 2). It should be noted that

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Tiles 2 and 4 (porcelain stoneware) require higher temperatures (1200ºC – 1225 ºC),

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leading to greater consumption of natural gas and consequently, there are a greater

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amount of air emissions from the firing operation (CO2, NOx, SOx, fluorine, chlorine,

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etc.), which contributes to several impacts categories, like GW, A, E, POF, ADf, and

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PM.

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Another process that could justify the environmental differences is the transportation of

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the raw and ancillary materials used for the manufacturing of the ceramic tiles. Tile 1 is

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the only case study that exclusively uses Portuguese raw materials, resulting in smaller

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transportation distances and, as a consequence, lower air emissions. On the other hand,

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Tiles 2, 3 and 4 use some imported materials from different European countries such as

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Ukraine and Spain (Tile 2) or Great Britain, Turkey and France (Tile 3 and 4), resulting

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in longer transportation distances, including transoceanic shipping. Moreover, Tiles 2

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and 4 require a subsequent treatment that includes grinding and polishing, resulting in

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the consumption of more electricity and water. In addition, Tile 1’s manufacturer

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recycles all the water used, resulting in a smaller impact with regard to WD.

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ACCEPTED MANUSCRIPT 3.1 Contribution of subsystems to total environmental impact (cradle-to-grave)

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Figure 2 presents the contribution of each subsystem (Subsystems 1, 2, 3, 4 and 5) of

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the ceramic tile life cycle to the total environmental impact for all impact categories.

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The main contribution to the environmental impact of all four tiles derives from

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Subsystem 1, for all impact categories except HTc, LU and ET. More specifically,

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Subsystem 1 has a contribution of 62-69% for GW, 66-73% for A, 40-48% for E, 74-

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81% for OD, 56-63% for POF, 37-77% for ADe, 70-79% for ADf, 43-73% for HTc, 53-

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56% for HTnc, 66-74% for PM, 3-5% for LU, 93-95% for WD and 4-9% for ET. The

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remaining subsystems have much smaller contributions that are similar to one another,

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for all impact categories except Subsystem 4, which has a contribution of 95%-97% for

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land use and 91-96% for ecotoxicity.

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Subsystem 2, which deals the transport scenario of 1000 km, is the second most relevant

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for GW (11% to 18%), A (11% to 18%), OD (8% to 14%), ADf (12% to 19%) and

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HTnc (16% to 23%), while Subsystem 3, which concerns the construction stage, is the

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third most relevant for HTc (8% to 17%), HTnc (13% to 16%) and WD (2% to 3%),

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explained by the contribution of the adhesive mortar and water used.

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Subsystem 4 is the most relevant for LU (95% to 97%) and ET (91% to 96%), revealing

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the importance of the building site itself and also the detergent usage in the

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cleaning/maintenance of the ceramic tile during the use stage, namely for ET. It is also

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the second most relevant for E (29% to 35%) and POF (25% to 32%).

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Subsystem 5 is the second most relevant for PM (10% to 14%) due to the type of

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activities performed at the end of life (demolition and their impacts on the air quality),

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and is the least relevant for the remaining categories,

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ACCEPTED MANUSCRIPT 3.2 Contribution of unit processes for Subsystem 1 (cradle-to-gate)

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Since Subsystem 1 (cradle-to-gate) is the most representative subsystem it will be

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assessed in more detail. The Figure 3 shows the contribution of each specific process

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included in the Subsystem 1: raw and ancillary material production (clay, kaolin,

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calcium carbonate, quartz and feldspar, glaze materials, lubricant, auxiliary materials for

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maintenance, atomized clay), packaging production (carton, packing film and European

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pallets), fuel production (diesel and natural gas), electricity production, wastewater

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treatment, on-site emissions (from the ceramic manufacturing processes, such as clay

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atomization, drying, firing, etc.) and finally, transport (of raw and ancillary materials to

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the manufacturer). The fuels consumed in all four tiles are used in the atomization,

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drying and firing (natural gas), and internal transport (diesel), although the main

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contribution derives from natural gas (98-99%).

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As shown in Figure 3, the production of raw and ancillary materials is an important

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contributor to ADe, representing 39% (Tile 1) to 84% (Tile 4). In particular, the kaolin

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production for Tiles 2, 3 and 4, involves more machinery and subsequent treatment than

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other mineral extractions. The production of raw and ancillary materials is also an

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important contributor to HTc (representing 33-80%), HTnc (34-41%), and E (12-38%

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for Tile 1, which has more processed raw materials) due to quartz, feldspar, kaolin and

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glaze materials production, while it is less relevant for A (5-24%), POF (8-23%) and

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PM2.5 (4-24% for Tile 1, which includes more processed materials).

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Packaging production is the dominant process for ET (75-86%), LU (37-62% due wood

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pallets used), HTnc (up to 22%) and HTc (up to 27%), while it is less relevant for

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almost all other impact categories, contributing less than 5%. The production of fuels is

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the major contributor to OD (67-77%) and ADf (53-59%).

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ACCEPTED MANUSCRIPT Electricity production is the dominant process with regard to A (40% to 44%), E (30%

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to 37%), POF (31% to 36%), ADe (44%, only for Tile 1), POF (32% to 36%) and WD

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(86% to 96%). It is also relevant in almost all categories, like GW (17% to 21%), OD

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(7% to 10%), ADe (11% to 28% for Tiles 2, 3 and 4), ADf (17% to 22%), HTc (9% to

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34%), HTnc (26% to 35%), PM2.5 (14% to 17%) and ET (10% to 22%). Wastewater

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treatment is the least relevant process for all impact categories (below 1%).

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On-site emissions, including the activities of the ceramic factory, are the most relevant

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process for GW (45% to 51% due to the burning operations), PM2.5 (43% to 67%) and

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LU (only for tile 1, with 43%, revealing the space and time occupied by this factory).

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On-site emissions are also important for POF (17% to 24%), E (5% to 16%) and A (4%

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to 9%), while for the other categories they are insignificant, representing less than 1%.

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Finally, transport is not the dominant process for any of the impact categories studied,

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although it is the third or fourth most relevant for A (13% to 37%), E (17% to 36%) and

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ADf (8% to 18%).

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4. Comparison with previous studies

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It should be noted that it is difficult to compare the results of the present study with

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previous findings because some studies do not present the results in absolute values but

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rather provide relative percentages. In addition, some of the impact assessment methods

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(characterization models) are different. Despite these limitations, the main conclusions

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from several studies are presented below, and Table 5 shows the impact category results

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published in the literature for ceramic tiles within the same typology.

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The results obtained in this study are quite consistent with the results obtained in other

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cradle-to-grave studies on ceramic tile materials like the ones from Italy (Nicoletti,

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2002) and from Spain (Benveniste et al., 2011; Ibáñez-Forés et al., 2011, 2013; Fullana

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ACCEPTED MANUSCRIPT and Palmer, 2011), in which the cradle-to-gate was the stage with the greatest

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contribution to the majority of the considered impact categories due to energy

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consumption and on-site activities (e.g. firing). It should also be noted that Benveniste

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et al. (2011) found the use phase to be the most significant for photochemical ozone

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formation (around 65%), eutrophication (around 43%) and water consumption (around

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70%). The latter result can be explained by type of cleaning agent (not identified in the

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study) used to wash the tiles and the frequency of cleaning (higher than those

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considered in this study). Another Spanish study by Fullana and Palmer (2011) obtained

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slightly lower results, with the manufacturing process mainly influencing AD, GW and

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NRE/CED (82%, 79% and 70%, respectively), while eutrophication and photochemical

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ozone formation were mainly influenced by the use stage. However, the absolute results

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for each stage and process were not presented.

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The studies (Almeida et al., 2013; Benveniste et al., 2011; Ibáñez-Forés et al., 2011,

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2013) also point out that within the cradle-to-gate, the firing unit process was one of the

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most relevant for the impact categories assessed (GW, A, E, POF) due to the high

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energy consumption. Using the Eco-indicator method, Nicoletti et al. (2002) also

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concluded that besides firing, the preparation of the mix body and frit fusion were the

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most relevant for acidification and human toxicity, respectively. This is also consistent

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with the present results, although for acidification the electricity production (Portuguese

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mix) is the main source (38-42% of the cradle-to-gate results).

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When comparing the studies of Benveniste et al. (2011), Bovea et al. (2010) and Ibañez-

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Forés et al. (2011, 2013), the absolute values obtained (Table 5) for global warming,

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eutrophication and abiotic fossil depletion are in the same order of magnitude, although

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the Portuguese results were higher (perhaps explained by the higher firing temperature),

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while for acidification and photochemicals, the Portuguese values are lower (maybe

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ACCEPTED MANUSCRIPT related to the type of natural gas used and the efficiency of combustion). Bovea et al.

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(2010) and Ibañez-Forés et al. (2011, 2013) reported transportation distances for raw

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materials (mainly atomized clay) and glaze that were quite lower (average of 20 km)

347

than the distance considered in the Portuguese study (where clay and glaze was

348

imported from aboard). That may also explain the differences in the impact categories

349

results. These authors also reported noise and the depletion of natural resources (another

350

impact category), but using different characterization methods.

351

Furthermore, in a comparative study on building materials by Bribián et al. (2011), the

352

main conclusions identified the influence of energy demand due to the high

353

consumption of natural gas in the ceramic tile manufacturing process. The energy

354

consumption result obtained in that article (NRE - 312.98 MJ/m2) is in the same order

355

of magnitude as in the present study (ADf), although a bit higher, while the result for

356

GW (17.14 kg/m2) is lower than obtained in this study. The relative percentages for the

357

influence of the firing process accounted for up to 80% of the production plant’s total

358

consumption, which is higher than the one determined in the present study.

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5. Actions for environmental impact improvement

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Based on the obtained results, some actions for improvement can be suggested in order

362

to decrease the environmental impact of the identified hotspots, including measures that

363

promote energetic efficiency and minimization of air emissions, as well as local

364

acquisition of raw materials. Bribián et al. (2011) stressed the importance of using local

365

raw and ancillary materials, as in some cases (such as Spain), materials imported from

366

distant countries resulted in the increase in energy demand and emissions by a factor of

367

1.6. The impact of the manufacturing process, mainly deriving from the firing process,

368

could be reduced using measures that lead to decreased fuel consumption, thus reducing

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15

ACCEPTED MANUSCRIPT air emission pollutants such as sulphur oxides (SOx), nitrogen oxides (NOx),

370

hydrofluoric acid (HF), and hydrochloric acid (HCl), and their associated environmental

371

impacts. Concerning transport as a hotspot, the first choice should be the use of local or

372

national raw and ancillary materials (if available and with similar quality and properties)

373

in order to decrease the transport distance of transport.

374

In this context, and although the measures are applicable to all four tiles, the

375

recommended actions for improvement will be assessed for Tile 4, which presented the

376

highest environmental impacts in almost all categories under study. Some of these

377

measures include those described in current policies, such as the EU ecolabel

378

implemented according to the European decision 2009/607/EC (European Commission,

379

2009) and the best available techniques (BAT) (European Commission, 2007) under the

380

scope of the EU Directive on Industrial Emissions (IED) (European Commission,

381

2010b), These measures will be assessed with regards to their effectiveness in reducing

382

environmental impact. Table 6 presents a summary of the suggested improvement

383

actions (IAs) specifically for Subsystem 1 (cradle-to-gate), including their investment

384

costs, cost savings per year and payback period (where applicable).

385

The improvement actions are related to:

387 388 389 390 391 392

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a) Measures taken within the ceramic factory/production site (IA1 or IA 2, IA3 and IA7)

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b) Measures related to raw material transport minimization (IA5) c) Combined measures of the two previous categories (IA4, IA6 and IA8)

The improvement actions are the following: •

IA1 consists of hot air recovery from the cooling zone of the roller kiln for its re-use in the burners located in the pre-heating zone of the kiln. This aims to

16

ACCEPTED MANUSCRIPT 393

reduce fuel consumption and the associated air emissions, and is considered a

394

BAT (EC, 2007) under the IED directive (CE, 2010b).

395

•

IA2 consists of hot air recovery from the cooling zone of the roller kiln for reuse in the dryers (saving natural gas for the dryers). It also aims to reduce the

397

fuel consumption and the associated air emissions. It is an alternative measure to

398

IA1 and also a BAT (EC, 2007). •

reducing electricity consumption (10%).

400 401

IA3 comprises upgrading the lighting systems in all factories, with the aim of

•

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IA4 is the joint implementation of IA1 and IA3. This option is based on the technically feasibility of these two measures, since they can both be integrated

403

into the factory and all elements involved are commercially available.

404

•

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IA5 includes the substitution of imported raw material (clay and glazed materials) and ancillary material from Spain and France with Portuguese

406

materials. This aims for impact minimization by reducing the transport distance

407

by truck. It should be noted that transport from Turkey and Great Britain by

408

transoceanic ship is “environmentally efficient.” •

because it is technically feasible to implement these complementary measures in

412 413

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IA6 is the combination of measures IA4 and IA5. This scenario was studied

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Subsystem 1.

•

IA7 considers the adoption of the environmental performance imposed by the

EU ecolabel for products within the product group of hard coverings (European

414

Commission, 2009). This includes criteria mainly associated with the production

415

site, namely the firing process (see Table 7, which contains the emission values

416

used to simulate IA7 for Tile 4). The implementation of this action would imply

417

the use of a number of measures, such as the recovery of excess heat from kilns,

17

ACCEPTED MANUSCRIPT especially from their cooling zone (similar to IA1 or IA2), heating curve

419

optimization, and additional equipment (cascade-type packed bed adsorbers or

420

bag filters) to decrease emissions to air, namely fluoride, chloride and particles,

421

or an update of the existing cascade-type packed bed adsorbers. The latter

422

cleaning systems consist of the reaction of a solid reagent (limestone) with the

423

flue-gas pollutants (mainly HF, SOx and HCl). This takes place in a chamber,

424

where the adsorbent sinks by gravity and through which the flue gases are

425

passed in a countercurrent. Regarding emissions to water, Tile 4 already fulfills

426

the limits of the EU ecolabel, so no additional measures are suggested regarding

427

this subject.

429

•

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IA8 is the combination of IA7 and IA5, and consists of the best possible scenario of all measures for Tile 4, although it is the most expensive.

As stated above, Table 6 presents the simple payback, defined as the period of time

431

needed to recover the initial investment (division of the initial investment costs by the

432

annual energy/environmental cost savings). Based on this parameter, it can be

433

concluded that IA1 to IA6 are profitable and economically sustainable measures, as

434

their payback periods are less than or equal to 3 years and the elements required are

435

available on the market. The two remaining measures (IA7 and IA8) have longer

436

payback periods.

437

Table 8 quantifies the impact reduction (expressed in %) compared to the initial

438

performance of Tile 4 for all the suggested improvement actions (scenarios). According

439

to the results presented in terms of individual measures (IA1, IA2, A3, IA5 and IA7),

440

IA7 (measures to meet environmental performance of EU ecolabel) and IA5

441

(substitution of foreign raw material with Portuguese materials) are the most effective

442

for reducing the impact. IA5 and IA7 are the most effective in reducing GW (5%) and

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18

ACCEPTED MANUSCRIPT ADf (5%), and IA5 is highly effective for reducing A (5%), E (7%), and HTnc (5%),

444

due to the influence of transport pollutants. For OD (7%), POF (4%) and PM (5%), IA7

445

achieves lower values, as was expected, since the measures apply to energy and

446

emissions reductions. IA3 is the most effective for WD (9%).

447

These findings are in line with the EU ecolabel indicators, which address the

448

manufacturing stage, with special attention given to the firing operation. They also

449

support the results from Bovea et al.’s (2010) study, which looked at similar measures

450

to IA1 and IA2 and found percentages of improvement of 2.1% (for E) to 11.8% (for

451

A). As our results show, the transport of raw materials is highly relevant, suggesting

452

that including a criterion regarding the transport of raw materials would be useful for a

453

future revision of the EU ecolabel.

454

It can also be stated that the reductions achieved by IA6 (reduction of fuel consumption,

455

electricity and transport distance) and IA8 (which includes the EU ecolabel and the

456

transport distance reduction) are in the same order of magnitude, although IA6 achieves

457

a greater reduction in almost all impact categories except for OD and PM. Finally, it

458

should be noted that the environmental impacts achieved by scenario IA6 (the

459

combination of measures IA4 and IA5) and scenario IA8 (the combination of IA7 and

460

IA5) are similar or even better than obtained for Tile 1 (see Table 4), which reveals that

461

improvements in the burning conditions of the firing process, electricity and raw

462

material transport are key elements in reducing environmental burdens.

463

The suggestion to include a criterion concerning transport of raw materials in a future

464

revision of the EU ecolabel is important, as transport is also relevant in terms of its

465

individual impacts, especially with regards to acidification and eutrophication

466

categories, but also global warming and abiotic fossil depletion.

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ACCEPTED MANUSCRIPT

6. Conclusions

469

Although the main technologies are similar (dry-pressing technique and single-firing in

470

roller kilns operating with natural gas) in the four ceramic tiles studied, they have

471

different environmental impacts within the same category (from 5 to 47%, except for

472

ADe, which was up to 179%). The kiln operation conditions, electricity consumption,

473

raw materials used and transport are key elements that justify the variability in impacts

474

in this study and on other international studies. In general, porcelain stoneware has a

475

higher impact than porcelain glazed tiles.

476

The tile production stage (cradle-to-gate), is the most significant stage, accounting for

477

more than 40% of each impact type, with the exception of land use and ecotoxicity, for

478

which the use stage is the most relevant (due to the building site itself and the use of

479

cleaning materials). Within the production stage, the processes with the greatest impact

480

are the production of electricity for A, E, POF, HTnc and WD; the production of raw

481

and ancillary materials for ADe, HTc and HTnc; on-site activities (especially the

482

burning of natural gas) for GW and PM2.5; the production of fuels (especially natural

483

gas) for OD and ADf; and the production of packaging for ET and LU.

484

Implementation of the EU ecolabel or reduction of the raw material transport distance

485

are the most environmentally efficient single measures, although the ecolabel performs

486

more poorly in terms of economic feasibility, as the payback is greater than 3 years. The

487

combination of measures, like heat recovery from the burners of the kiln (a BAT),

488

lighting system improvements, and transport minimization (IA6) are the most effective

489

for environmental impact reduction.

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ACCEPTED MANUSCRIPT 491

Acknowledgements

492

The authors gratefully acknowledge the CTCV (Technology Center for Ceramic and

493

Glass - Portugal) for its financial support of this work.

494

References

496

Almeida, M.I., Dias, A.C., Demertzi, M., Arroja, L., 2015. Contribution to the

497

development of product category rules for ceramic bricks. J. Clean. Prod. 92, 206-215.

498

Almeida, M.I.A, Demertzi, M., Dias, A.C., Arroja, L., 2013. Environmental product

499

declaration: for ceramic tile, Energy for Sustainability, Coimbra, Portugal.

500

APICER, 2009. Strategic Plan for The Ceramic Sector in Portugal. APICER, Coimbra,

501

Portugal.

502

Asif, M.M., Muneer, T., Kelley, R., 2007. Life cycle assessment: a case study of a

503

dwelling home in Scotland. Build Environ. 42(3), 1391–1394.

504

Benveniste, G., Gazulla, C., Fullana, P., Celades, I., Ros, T., Zaera, V., Godes, B., 2011.

505

Life cycle assessment and product category rules for the construction products. The

506

floor and wall tiles sector case study. Inf. la Construcción 63, 71–81 (in Spanish).

507

Boch, P.N., Niepce J.C., 2007. Ceramic Materials: Processing, Properties, and

508

Applications. ISTE Publications, Newport Beach, USA.

509

Bovea, M.D., Saura, U., JL. Ferrero, J. Giner, 2007. Cradle-to-gate study of red clay for

510

use in the ceramic industry. Int J LCA. 12(6):439–47.

511

Bovea, M.D., Díaz-Albo, E., Gallardo, A., Colomer, F.J., Serrano, J., 2010

512

Environmental performance of ceramic tiles: Improvement proposals. Materials and

513

design. 31:39–41.

AC C

EP

TE D

M AN U

SC

RI PT

495

21

ACCEPTED MANUSCRIPT Bribián, Z.C., Capilla, V.A., Usón, A.A., 2011. Life cycle assessment of building

515

materials: comparative analysis of energy and environmental impacts and evaluation of

516

the eco-efficiency improvement potential. Build Environ. 46(5), 1133-1140.

517

Calkins, M., 2003. Materials for Sustainable Sites: A Complete Guide to the Evaluation,

518

Selection and Use of Sustainable Construction Materials. Wiley Publications, San

519

Francisco, USA.

520

CEN, 2013 Sustainability of construction works - Environmental product declarations -

521

Core rules for the product category of construction products, EN 15804:2012 + A 1,

522

European Committee for Standardization. Brussels, Belgium.

523

Ecoinvent, 2012. The life cycle inventory. Data V. Swiss Centre for Life Cycle

524

Inventories, Bern Switzerland.

525

European Ceramic Industry Association, 2012. Paving the Way to 2050 - The Ceramic

526

Industry Roadmap. Publications Office of the European Union, Brussels., Belgium.

527

European Commission, 2007. Reference document on best available techniques (BAT)

528

reference document (BREF) in the ceramic manufacturing industry. Institute for

529

Prospective Technological Studies, Seville, Spain.

530

European Commission, 2009. Decision 2009/607/EU of the European Parliament and

531

the Council of 9 July establishing the ecological criteria for the award of the

532

Community ecolabel to hard coverings. Official Journal of the European Union L

533

208/21.

534

European Commission, 2010a. Energy-efficient buildings PPP, multi-annual road map

535

and longer term strategy. Publications Office of the European Union, Brussels,

536

Belgium.

537

European Commission, 2010b. Directive 2010/75/EU of the European Parliament and

538

the Council of 24 November on industrial emissions. Official Journal of the European

AC C

EP

TE D

M AN U

SC

RI PT

514

22

ACCEPTED MANUSCRIPT Union. Publications Office of the European Union, Brussels, Belgium, L 334/17 on

540

17.12.2010.

541

European Commission, 2011a. EU Energy and Transport in Figures Pocketbook.

542

Publications Office of the European Union. Brussels, Belgium.

543

European Commission. 2011b. Regulation 305/2011, harmonized conditions for the

544

marketing of construction products and repealing Council Directive 89/106/EEC.

545

Eurostat, 2014. Ceramic and Clay Products Manufacturers. Eurostat, Luxembourg.

546

Frej, A. (2005). Green Office Buildings: a Practical Guide to Development. ULI - The

547

Urban Land Institute, Washington D.C., USA.

548

Fullana i Palmer, P., 2011. Life cycle assessment of ceramic tiles. European Parliament

549

Ceramics Forum debate. Brussels, Belgium.

550

Guinée, J. G., Gorrée, M., Heijungs, R., Huppes, G., Kleijn, R., de Koning, A., et al.,

551

2001. Life cycle assessment - An operational guide to the ISO standards. Centre of

552

Environmental Science. Leiden, Netherlands.

553

Hischier. R., W. B., Weidema. B., Althaus, H.J., Bauer, C., Doka, G., Dones, R., et al.,

554

2007. Implementation of life cycle impact assessment methods. Ecoinvent report No. 3,

555

v2.1. Ecoinvent Center, Dübendorf, Switzerland.

556

Huijbregts, M.A.J., Rombouts, L.J.A., Hellweg, S., Frischknecht, R., Hendriks, A.J.,

557

van de Meent, D., Ragas, A.M.J., Reijnders L, Struijs, J., 2005. Is cumulative fossil

558

energy demand a useful indicator for the environmental performance of products?.

559

Environ. Sci. Technol. 40 (3), 641-648.

560

Ibáñez-Forés, V. B., Bovea, M.D., Simó, A., 2011. Life cycle assessment of ceramic

561

tiles. Environmental and statistical analysis. Int. J. Life Cycle Assess. 16, 916–928.

562

Institute, W., 2009. Unburned Clay Building Materials. Wuppertal Institute. Wuppertal,

563

Germany.

AC C

EP

TE D

M AN U

SC

RI PT

539

23

ACCEPTED MANUSCRIPT Ibáñez-Forés, V., Bovea, M.D., Azapagic, A., 2013. Assessing the sustainability of Best

565

Available Techniques (BAT): methodology and application in the ceramic tiles

566

industry. J. Clean. Prod. 51, 162-176.

567

ISO, 2006a. ISO 14040:2006, Environmental Management - Life Cycle Assessment -

568

Principles and frameworks. Geneva, Switzerland.

569

ISO, 2006b. ISO 14044:2006, Environmental Management - Life Cycle Assessment –

570

Requirements and guidelines. Geneva, Switzerland.

571

European Commission-Joint Research Centre (EC-JRC) - Institute for Environment and

572

Sustainability: International Reference Life Cycle Data System (ILCD) (2011). ILCD

573

Handbook: Recommendations for Life Cycle Impact Assessment in the European

574

context. First edition November 2011. Luxemburg. Publications Office of the European

575

Union.

576

Koroneos, C.D., Dompros, A., 2007. Environmental assessment of brick production in

577

Greece. Build Environ. 42(5), 2114–2123.

578

Loijos, A.S., Santero, N., Ochsendorf, J., 2013. Life cycle climate impacts of the US

579

concrete pavement network. Resources, Conservation and Recycling, 72, 76-83.

580

Nebel, B.Z., Zimmer, B., Wegener, G., 2006. Life cycle assessment of wood coverings.

581

Int. J. Life Cycle Assess. 11(3), 172-182.

582

Nicoletti, G.N., Notarnicola, B., Tassielli, G., 2002. Comparative life cycle assessment

583

of flooring materials: ceramic versus marble tiles. J. Clean. Prod. 10(3), 283–296.

584

Ortiza, O.C., Castellsa, F., Sonnemann, G., 2009. Sustainability in the construction

585

industry: A review of recent developments based on LCA. Constr. Build. Mat. 23(1),

586

28-39.

AC C

EP

TE D

M AN U

SC

RI PT

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24

ACCEPTED MANUSCRIPT Quinteiro, P., Almeida, M., Dias, A.C., Araújo, A., Arroja, L., 2014. The carbon

588

footprint of ceramic products, in: Muthu, S.S. (Ed.), Assessment of Carbon Footprint in

589

Different Industrial Sectors. Volume 1. Springer Publications, pp. 113–150.

590

Rademaekers, K.A., Asaad, S.S.Z., Berg, J., 2011. Study on the competitiveness of the

591

european companies and resource efficiency. ECORYS. Rotterdam, Netherlands.

592

Rosenbaum R.K., Bachmann T.M., Gold L.S., Huijbregts M.A.J., Jolliet O., Juraske R.,

593

Köhler A., Larsen H.F., MacLeod M., Margni M., McKone T.E., Payet J., Schuhmacher

594

M., van de Meent D. and Hauschild M.Z., 2008. USEtox - The UNEP-SETAC toxicity

595

model: recommended characterisation factors for human toxicity and freshwater

596

ecotoxicity in Life Cycle Impact Assessment. Int. J. Life Cycle Assess. 13(7): 532-546

597

Werner, F.R., Richter, K., 2007. Wooden building products in comparative LCA. Int. J.

598

Life Cycle Assess. 12(7), 470-479.

599

Zhao, M.G., Gong, X., Shi, F., Fang, M., 2013. Life cycle assessment of ready-mixed

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concrete. Materials Science Forum, 743, 234-238.

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ACCEPTED MANUSCRIPT 1

Figure Captions

2

Figure 1: System boundary of the ceramic tiles system under study (cradle-to-grave).

4

The numbered circles represent the subsystems of the life cycle. Subsystem 1 - cradle-

5

to-gate, Subsystem 2 - transport, Subsystem 3 - installation process, Subsystem 4 - use,

6

Subsystem 5 - final disposal.

RI PT

3

7

Figure 2 - Contribution of each subsystem to the total environmental impact for GW, A,

9

E, OD, POF, ADe, ADf, HTc, HTnc, PM, LU and WD of each tile (T1, T2, T3 and T4) per FU (1m2 of ceramic tiles).

11

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10

SC

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Figure 3 - Contribution of each process to the environmental impact of the Subsystem 1

13

for each tile (1, 2, 3 and 4) per FU (1m2 of ceramic tiles).

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Table Captions

2 3

Table 1: Data inventory for the manufacturing stage system per functional unit (1m2 of

5

ceramic tiles produced in Portugal).

RI PT

4

6 7

Table 2: Percentages of natural gas consumption for each ceramic tile case.

9

SC

8

Table 3: Impact categories, parameter, units, method and references.

M AN U

10 11

Table 4: Environmental results per functional unit (1m2 of ceramic tiles produced in

12

Portugal).

13

Table 5: Comparison of environmental results per functional unit (1m2) published in the

15

literature.

TE D

14

16

Table 6: Improvement actions (IA), their investment costs, cost savings per year and

18

payback.

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17

20

Table 7: Ecolabel values used during the manufacturing stage for the improvement

21

action number 7 (IA7).

22 23

Table 8: Percentage of reduction achieved per functional unit (1m2 of ceramic tiles

24

produced in Portugal) (%) for each impact measure (IA).

1

ACCEPTED MANUSCRIPT Table 1 - Data inventory for the manufacturing stage system per functional unit (1m2 of ceramic tiles produced in Portugal). Units Tile 1

Tile 2

kg kg kg kg kg kg kg kg kg kg kg kg L kWh GJ MJ kg kg

1.60E+00 1.60E-03 1.73E+00 -1.00E-01 8.10E-02 1.70E-02 9.10E-02 -8.10E+00 1.00E+00 6.00E-01 1.25E+01 4.10E+00 9.40E-02 7.00E-01 1.50E-02 1.50E-03

6.30E+00 4.28E+00 8.99E+00 2.20E-01 -3.70E-01 -2.23E-01 --1.00E-01 8.00E-01 1.50E+01 5.40E+00 1.16E-01 1.00E+00 3.00E-01 2.60E-02

Total waste

kg

8.00E-01

2.43E+00

2.01E+00

4.04E+00

M AN U

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AC C

5.40E+00 5.20E+00 6.28E+00 6.53E+00 -2.30E-01 1.13E-01 3.70E-04 1.69E+00 -7.20E-01 1.00E-01 3.53E+01 5.76E+00 1.22E-01 1.87E+00 2.54E-01 2.57E-02

kg kg kg

----

----

2.57E-04 9.39E-05 2.96E-04

1.19E-04 3.21E-04 7.14E-04

g g g g g g

3.30E-01 1.13E+00 1.17E+00 7.16E+00 2.63E+00 1.90E+00

6.05E+00 9.00E-02 -1.46E+01 9.80E+00 9.00E-01

4.78E+00 6.90E-01 3.80E-01 1.14E+01 8.10E-01 7.20E-01

4.67E+00 1.00E-01 5.90E-01 1.08E+01 4.68E+00 1.09E+00

EP

Emissions to water: Suspended solids BOD5 COD Emissions to air: Particles Fluorine Chlorine CO NOx SOx

Tile 4

1.08E+01 5.00E-02 6.54E+00 -3.30E-01 1.50E-02 5.90E-01 5.60E-03 --5.00E-01 5.00E-01 2.44E+01 4.90E+00 8.90E-02 7.00E-01 9.50E-02 1.30E-02

SC

Clays Kaolin Feldspar Perlite Talc Colourings Glazes Additives (silicates. etc.) Sand Atomized clays Scrape unfired Wastes and subproducts Water Electricity Natural gas Diesel Packing material: carton Packing material: plastic Outputs

Tile 3

RI PT

Inputs

ACCEPTED MANUSCRIPT

Table 2: Percentages of natural gas consumption for each ceramic tile case. Tile 3 30% 25% 45%

Tile 4 35% 15% 50%

RI PT

Tile 2 30% 25% 45%

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Clay atomisation Drying Firing

Tile 1 33% 17% 50%

ACCEPTED MANUSCRIPT Table 3: Impact categories, parameter, units, method and references.

Global warming potential, GWP; Acidification potential of soil and water, AP; Eutrophication potential, EP; Depletion potential of the stratospheric ozone layer, ODP; Formation potential tropospheric ozone, POCP; Abiotic depletion potential (ADP elements) for nonfossil resources Abiotic depletion potential (ADP-fossil fuels) for fossil resources

Global Warming (GW) Acidification for soil and water (A) Eutrophication (E) Ozone Depletion (OD)

layer

Photochemical oxidation formation (POF) Depletion of abiotic elements (ADe)

Human toxicity (HT)

Human toxicity, noncancer effects

Ecotoxicity

AC C

Ecotoxicity (ET)

Land use Water depletion

EP

Water depletion (WD)

TE D

Human toxicity (HT)

Human toxicity, cancer effects

Particulate matter (PM) Land use (LU)

kg CO2 equiv kg SO2 equiv 3-

kg (PO4) equiv

resource

Method and references IPPC, CML-IA, EN15804+A1 (CEN, 2013) CML-IA, EN15804+A1 (CEN, 2013) CML-IA, EN15804+A1 (CEN, 2013)

kg CFC 11 equiv

CML-IA, EN15804+A1 (CEN, 2013)

kg Ethene equiv

CML-IA, EN15804+A1 (CEN, 2013)

kg Sb equiv

M AN U

Depletion of abiotic fossil fuels (ADf)

Unit expressed per functional unit

RI PT

Parameter

SC

Impact Category

MJ, net calorific value

CTUh

CTUh

CML-IA, EN15804+A1 (CEN, 2013)

CML-IA, EN15804+A1 (CEN, 2013)

Usetox (Rosenbaum Köhler,2008) 2011) Usetox (Rosenbaum Köhler,2008) 2011)

ILCD, 2008, (EC-JRC, ILCD, 2008, (EC-JRC,

kg PM2.5 eq

ILCD, (EC-JRC, 2011)

kg C deficit

ILCD, (EC-JRC, 2011) ILCD, (EC-JRC, 2011)

3

m water equiv CTUh

Usetox ILCD, (Rosenbaum 2008) (ECJRC, 2011)

ACCEPTED MANUSCRIPT Table 4: Environmental results per functional unit (1m2 of ceramic tiles produced in Portugal). Tile 2

Tile 3

Tile 4

kg CO2 eq kg SO2 eq kg PO4 eq kg CFC-11 eq kg C2H4 kg Sb eq MJ eq CTUh CTUh kg PM2.5 kg C deficit m3 CTUe

2.01E+01 5.98E-02 1.58E-02 1.74E-06 3.65E-03 1.63E-06 2.52E+02 3.32E-08 5.39E-07 9.34E-03 2.66E+02 1.34E+01 2.42E+00

2.13E+01 7.22E-02 1.71E-02 1.83E-06 4.35E-03 3.56E-06 2.69E+02 3.52E-08 5.50E-07 1.16E-02 2.62E+02 1.79E+01 2.50E+00

2.07E+01 6.97E-02 1.66E-02 1.65E-06 3.92E-03 2.20E-06 2.56E+02 7.60E-08 6.74E-07 1.31E-02 2.60E+02 1.53E+01 2.42E+00

2.33E+01 8.28E-02 1.90E-02 2.05E-06 4.61E-03 4.55E-06 3.11E+02 4.21E-08 6.42E-07 1.29E-02 2.66E+02 1.97E+01 2.55E+00

EP AC C

SC

RI PT

Tile 1

TE D

GW A E OD POF ADe ADf HTc HTnc PM LU WD ET

Units

M AN U

Impact category

ACCEPTED MANUSCRIPT

OD POF

-kg CO2 eq kg SO2 eq kg PO4 eq kg CFC-11 eq kg C2H4

ADf

MJ eq

SC Cradle to grave

Cradle to gate

CML CML 2001 CML 2001 CML 2001 2001 Castellon Spain Spain Spain All types All types glazed unspecified (minimum) (maximum) stoneware 8.46E00 8.70E+00 1.80E+01 6.10E+00 5.32E-02 2.85E-02 6.87E-02 4.50E-02 1.70E-03 2.28E-03 3.80E-03 9.35E-03 2.49E-07 9.48E-07 2.12E-06 6.50E-07 3.75E-03 Not available

AC C

Type of ceramic tile GW A E

---

Cradle to grave

M AN U

LCA assessment method Geographical coverage

Cradle to gate

--

Ibáñez-Forés et al. (2011)

IbáñezForés et al. (2013)

TE D

Type of LCA approach

Units

EP

Impact category

Bovea et al. (2010)

RI PT

Table 5: Comparison of environmental results per functional unit (1m2) published in the literature.

1.16E-03 Not available

3.16E-03 Not available

1.70E-03 Not available

Benveniste et al. (2011)

Cradle to grave CML 2001 (pr EN15804) Spain porcelain stoneware 1.80E+01 7.90E-02 9.60E-03 2.10E-07

Cradle to grave CML 2001 (pr EN15804) Spain Glazed tiles 1.70E+01 7.00E-02 9.10E-03 1.70E-07

2.00E-02 3.00E+02

2.00E-02 2.90E+02

ACCEPTED MANUSCRIPT Table 6: Improvement actions (IA), their investment costs, cost savings per year and payback.

IA 6 IA 7

120,000 1880 18,800 121,880

40,000 1,080 6,373 41,080

3 1.75 2.95 3

--121,880

20,000 61,080

-1.99

350,000 350,000

35,000 55,000

10 6.36

AC C

EP

TE D

M AN U

IA 8

Payback (year)

RI PT

IA 2 IA 3 IA 4 IA 5

Improvement actions (IA) Heat recover to the burners of the kiln Heat recover to the dryer Lighting system IA1+IA3 Transport substitution (Turkey to Portugal) IA4+IA5 Enviromental performance according to Ecolabel IA7+IA5

Cost savings (euros/year)

SC

IA 1

Investment (euros)

ACCEPTED MANUSCRIPT

RI PT

SC

1.5 0.15

Fe

Pb

AC C

EP

TE D

M AN U

Emission to water

Emission to air:

Table 7: Ecolabel values used during the manufacturing stage for the improvement action number 7 (IA7). Parameter / Criteria Limit value Unit Energy Requirements for firing 3.5 MJ/kg of product Fresh Water Specific Consumption 1880 l/kg of product Particulate matter (Dust) 200 mg/m2 Fluorides (as HF) mg/m2 200 Nitrogen oxides (as NOx) 2500 mg/m2 Sulphur dioxides (as SO2) 1500 mg/m2 Suspended solid (SS) 40 mg/l Cd 0.015 mg/l 0.15 mg/l Cr(VI) (not applicable) mg/l mg/l

ACCEPTED MANUSCRIPT Table 8: Percentage of reduction achieved per functional unit (1m2 of ceramic tiles produced in Portugal) (%) for each impact measure (IA).

IA3

IA4

GW A E OD POF ADe ADf HTc HTnc PM LU WD ET

3.0 0.8 0.6 4.4 1.6 0.0 3.3 0.0 0.1 2.9 0.0 0.0 0.0

1.3 0.3 0.2 1.8 0.7 0.0 1.3 0.0 0.0 1.2 0.0 0.0 0.0

2.1 3.8 3.1 0.9 3.1 1.2 1.9 4.1 3.9 1.6 0.2 8.6 1.0

5.0 4.6 3.6 5.3 4.8 1.2 5.3 4.2 4.0 4.5 0.2 8.6 1.0

TE D EP AC C

IA5 5.4 4.7 6.7 3.4 2.1 0.1 4.9 0.6 4.5 1.9 0.0 0.2 0.2

IA6 10.5 9.3 10.3 8.7 6.9 1.2 10.2 4.7 8.5 6.4 0.2 8.8 1.2

IA7 4.8 2.6 3.4 6.6 4.3 0.0 5.0 0.0 0.1 4.7 0.0 0.0 0.0

IA8 10.2 7.4 10.1 10.0 6.4 0.1 9.9 0.6 4.6 6.7 0.0 0.2 0.2

RI PT

IA2

SC

IA1

M AN U

Impact category (%)

AC C

EP

TE D

M AN U

SC

RI PT

ACCEPTED MANUSCRIPT

Figure 1: System boundary of the ceramic tiles system under study (cradle-to-grave). The numbered circles represent the subsystems of the life cycle. Subsystem 1 - cradle-to-gate, Subsystem 2 - transport, Subsystem 3 - installation process, Subsystem 4 - use, Subsystem 5 - final disposal.

1,0E-01

ACCEPTED MANUSCRIPT 8,0E-02 A (kg SO2 eq)

2,0E+01

1,0E+01

0,0E+00 T1

T2

T3

T1

T4

1,0E-02 5,0E-03

T4

2,0E-06 1,5E-06 1,0E-06 5,0E-07 0,0E+00

T1

T2

T3

T4

T1

5,0E-03

5,0E-06

4,0E-03

4,0E-06

ADe (kg Sb eq)

POF (C2H4 eq)

T3

3,0E-03 2,0E-03 1,0E-03 0,0E+00

3,0E-06 2,0E-06 1,0E-06

T2

T3

T4

3,5E+02 3,0E+02

HTc (CTUh)

2,5E+02

M AN U

0,0E+00

T1

1,5E+02 1,0E+02 5,0E+01 0,0E+00 T2

T3

T4

TE D

T1

8,0E-07 6,0E-07 4,0E-07

T1

3,0E+02

AC C

2,5E+02

T2

T3

T3

T4

T1

T2

T3

T4

T1

T2

T3

T4

T1

T2

T3

T4

T1

T2

T3

T4

8,0E-08 7,0E-08 6,0E-08 5,0E-08 4,0E-08 3,0E-08 2,0E-08 1,0E-08 0,0E+00

1,2E-02 1,0E-02 8,0E-03 6,0E-03 4,0E-03 2,0E-03 0,0E+00

T4 2,5E+01 2,0E+01 WD (m3 eq)

0,0E+00

EP

2,0E-07

T2

1,4E-02

PM (kg PM2.5 eq)

2,0E+02

RI PT

OD (kg CFC-11 eq)

E (kg PO4 eq)

1,5E-02

0,0E+00

ADf (MJ)

T2

2,5E-06

2,0E-02

HTnc (CTUh)

4,0E-02 2,0E-02

0,0E+00

LU (kg C deficit)

6,0E-02

SC

GW (kg CO2 eq)

3,0E+01

2,0E+02 1,5E+02 1,0E+02

1,5E+01 1,0E+01 5,0E+00

5,0E+01 0,0E+00

0,0E+00

T1

T2

T3

T4

T1

T2

T3

T4

3,0E+00

ET (CTUe)

2,5E+00 2,0E+00 1,5E+00 1,0E+00 5,0E-01 0,0E+00

Figure 2 - Contribution of each subsystem to the total environmental impact for GW, A, E, OD, POF, ADe, ADf, 2 HTc, HTnc, PM, LU and WD of each tile (T1, T2, T3 and T4) per FU (1m of ceramic tiles).

ACCEPTED MANUSCRIPT 7.0E-02

2.0E+01

A (kg SO2 eq)

GW (kg CO2 eq)

6.0E-02

1.5E+01 1.0E+01 5.0E+00

5.0E-02 4.0E-02 3.0E-02 2.0E-02 1.0E-02

0.0E+00

0.0E+00

T1

T2

T3

T4

T1

1.0E-02

4.0E-03 2.0E-03

1.5E-06 1.0E-06 5.0E-07 0.0E+00

0.0E+00 T1

T2

T3

T1

T4

3.0E-03

4.0E-06

2.0E-03 1.5E-03

5.0E-04

T3

T4

3.0E-06 2.0E-06 1.0E-06

M AN U

1.0E-03

T2

SC

ADe (kg Sb eq)

2.5E-03

POF (kg C2H2 eq)

T4

RI PT

OD (kg CFC-11 eq)

E (kg PO4 eq)

6.0E-03

0.0E+00

0.0E+00 T1

T2

T3

T4

2.5E+02

T1

T2

T3

T4

T1

T2

T3

T4

T1

T2

T3

T4

T1

T2

T3

T4

6.0E-08 5.0E-08

HTc (CTUh)

2.0E+02

ADf (MJ)

T3

2.0E-06

8.0E-03

1.5E+02 1.0E+02 5.0E+01

4.0E-08 3.0E-08 2.0E-08 1.0E-08

0.0E+00 T2

4.0E-07 3.0E-07

1.0E-07 0.0E+00 T1

T2

T3

T4

1.2E-02 1.0E-02 8.0E-03 6.0E-03 4.0E-03 2.0E-03 0.0E+00

T4 2.0E+01

AC C

1.4E+01

EP

2.0E-07

T3

PM (kg PM2.5 eq)

T1

TE D

0.0E+00

HTnc (CTUh)

T2

1.0E+01

WD (m3 eq)

LU (kg C deficit)

1.2E+01 8.0E+00 6.0E+00 4.0E+00

1.5E+01 1.0E+01 5.0E+00

2.0E+00 0.0E+00

T1

0.0E+00

T2

T3

T4

T2

T3

T4

2.5E-01

ET (CTUe)

2.0E-01 1.5E-01 1.0E-01 5.0E-02 0.0E+00 T1

Figure 3 - Contribution of each process to the environmental impact of the Subsystem 1 for each tile (1, 2, 3 2 and 4) per FU (1m of ceramic tiles).

ACCEPTED MANUSCRIPT

Manufacturing stage (cradle-to-gate) is a hot spot for almost all categories; The use stage is important for land use and ecotoxicity; The porcelain stoneware has higher impacts that porcelain glazed ceramic tiles; Impact can vary from 5 to 47%, except for ADe which can reach up to 179%; Reduction of energy consumption and transport minimize impacts in about 10%;

AC C

EP

TE D

M AN U

SC

RI PT

• • • • •