Wordcount: 7906 words 1 Comparative combinations of façade-building systems and thermal insulation 2 materials for different climatic conditions: an environmental assessment 3 1,2 *Jorge Sierra-Pérez , Jesús Boschmonart-Rives 1,3 and Xavier Gabarrell 1,4 4 1 Sostenipra (ICTA – IRTA - Inèdit Innovació SL) 2014 SGR 1412. Institute of Environmental Science and Technology 5 (ICTA), Universitat Autònoma de Barcelona (UAB), 08193 – Cerdanyola del Vallès (Bellaterra), Barcelona, Spain. 6 2 Centro Universitario de la Defensa. Ctra. de Huesca s/n, 50.090, Zaragoza, Spain 7 3 Inèdit Innovació, S.L. Parc de Recerca de la Universitat Autònoma de Barcelona (UAB), 08193 – Cerdanyola del 8 Vallès (Bellaterra), Barcelona, Spain 9 4 Department of Chemical Engineering (XBR), Universitat Autònoma de Barcelona (UAB), 08193 – Cerdanyola del 10 Vallès (Bellaterra), Barcelona, Spain 11 *Corresponding author: jsierra@unizar.es 12 Abstract 13 In the European Union, the building sector accounts for more than 40% of the energy 14 consumption and environmental impacts, representing the area with the greatest 15 potential for intervention. In addition to the existing policies that promote the energy 16 efficiency use in building, the embodied energy in the materials and the included 17 processes in the building life cycle should be considered. Insulation materials are an 18 essential part of the energy savings during the use of the building, but also of the 19 embodied energy in the building construction. Most environmental studies about 20 insulation materials at date had focused on the environmental impacts of the 21 production of materials. This article aims to broaden the scope and provides a detailed 22 environmental assessment of various thermal insulation materials applied in different 23 types of façade systems in each Spanish climate zones by means of LCA from cradle 24 to site approach methodology. The results show that the most impacting alternative is 25 the ventilated façade in combination with the most impacting insulation materials: 26 mineral wool and expanded polystyrene. Meanwhile the most advisable façade in all 27 the climate zones is the external insulation option in combination with any alternative of 28 insulation. The environmental impacts are very different between insulation materials, 29 so it can be noted the relevance of the choice of the insulation. This behaviour is 30 determined by the physical and insulation properties of different materials, but also the 31 environmental performance of them. 32 Keywords 33 Insulation materials, LCA, environmental impacts, embodied energy, sustainable 34 construction, building façade. 35 Pre-print of: Sierra-Pérez, Jorge, et al. "Environmental assessment of façade-building systems and thermal insulation materials for different climatic condicions" in Journal of Cleaner Production Vol. 113 (February 2016), p. 102-113. Elsevier. The final version is available at DOI 10.1016/ j.jclepro.2015.11.090 36 Highlights 37 · Environmental impacts of common insulation applied in façade systems have 38 compared 39 · ETICS with any insulation and in any climate zone is the most sustainable alternative 40 · The most sustainable insulation is SW, meanwhile MW and EPS have the greatest 41 impacts 42 · Importance of insulation choice because their differences in environmental impacts 43 Nomenclature EPBD Energy Performance of Buildings Directive XPS Extruded polystyrene EPS Expanded polystyrene PU Polyurethane MW Mineral wool SW Stone wool ETICS External Thermal Insulation Composite System NZEB Nearly zero-energy building SME Small and medium-sized enterprises CO2 Carbon dioxide LCA Life cycle assessment DIN German Institute for Standardization DU Declared unit EN European norm CML Institute of Environmental Sciences ADP Abiotic depletion potential AP Acidification potential EP Eutrophication potential GWP Global warming potential OLDP Ozone layer depletion PCOP Photochemical oxidation EE Embodied energy CED Cumulative energy demand 44 2 45 1. Introduction 46 In the European Union (EU), the building sector represents one of the leading 47 environmental points, accounting for more than 40% of the energy consumption and 48 environmental impacts [1]. But also represents the area with the greatest potential for 49 intervention [2], wherein increasing building energy efficiency is crucial for the 50 transformation of the UE energetic framework [3]. Indeed, the sustainability concerns of 51 Horizon 2020 could have a strong impact on the future of the European construction 52 industry [4]. A more sustainable construction and use of buildings in the EU would 53 decrease 42% of final energy consumption, about 35% of greenhouse gas emissions 54 and more than 50% of all extracted materials. Moreover, it could also help us save up 55 to 30% water [5]. Currently, existing policies promote energy efficiency and renewable 56 energy use in buildings, i.e. the European Energy Performance of Buildings Directive 57 2002/91/EC (EPBD) [1]. This directive introduces the concept of nearly zero-energy 58 building (NZEB), and establishes that all new constructions have to NZEB by the 31st 59 of December of 2020. For public buildings, the deadline is even sooner – the end of 60 2018. The implementation of these regulations means less energy consumption during 61 the use phase of the building, operating energy, expended in maintaining the inside 62 environment through processes such as heating and cooling, lighting and operating 63 appliances. In addition to operating energy, the total life cycle energy of a building also 64 includes the embodied energy, the sequestered energy in building materials during all 65 processes of production, on-site construction, final demolition and disposal. And 66 consequently, it is concluded that much effort has been made towards the reduction of 67 operational energy by increasing the energy efficiency of buildings. However, as 68 operational energy is reduced, the percentage of the embodied energy in the total 69 energy consumption of the buildings becomes increasingly prevalent [6–8]. Therefore, 70 according to European Commission [5], it is needed to be further strengthened and 71 complemented with policies for resource efficiency, which look at a wider range of 72 environmental impacts across the life-cycle of buildings and infrastructure. 73 Recent studies on embodied energy and embodied CO2 have been developed [9–12], 74 considering the significance of embodied energy and carbon inherent in building 75 materials. A certain awareness of the embodied energy contents of building materials 76 could encourage the use of not only production and development of low embodied 77 energy materials, but also their preference among construction design and industry to 78 require energy [13]. Consequently less use of resources will lead to fewer emissions 79 and therefore reducing the environmental impacts in the construction of the building. 80 Moreover a comprehensive assessment of the energy use and environmental impacts 81 of buildings requires a life-cycle perspective to quantify the various impacts and to 82 identify improvement opportunities towards more sustainable solutions. Life cycle 83 assessment (LCA) methodology [13] has gained increased international acceptance in 84 building sector, identifying the potential environmental impacts throughout a product 85 life-cycle [14]. In addition to identifying improvements in the environmental performance 86 of different constructive solutions, LCA is widely used to compare different alternatives 87 in the design of buildings. On the one hand, most studies have focused on building 88 solutions: different types of exterior walls [15–17], the structure of building [18] and 89 more recently, the green roofs [19,20]. In these studies the parameters used to 90 compare different alternatives are the composition of the building system and the 3 91 materials used in each solution. As well as considering the location of the building as a 92 parameter for comparison between alternatives [21–23]. On the other hand, LCA can 93 be a support tool in the choice of the materials to include into the solutions. For 94 example, Zabalza [24] used the process-based LCA framework to evaluate 95 environmental impacts of different building materials used in different construction 96 solutions, including: floors, roofs, the structure and insulation materials. It is this latter 97 group of materials which has recently increased the interest in the environmental field 98 [25–28]. 99 The thermal insulation materials have an important role because, in addition to 100 influencing the environmental impacts of construction, it will also influence in the use 101 phase of the building. So a first move towards efficient use of operating energy is to 102 reduce the energy required to keep a good interior temperature. According to the NZEB 103 and the use of passive solutions for the envelope will result in increased insulation 104 thicknesses in buildings. Thus, the contribution of these materials to the life cycle 105 environmental impact of buildings will be critical [28], so that the environmental 106 assessment of different insulation solutions has become an strategic issue in building. 107 Almost all LCA of insulation materials performed are focused on the comparison 108 between the environmental impacts generated by a given amount of material with the 109 same thermal insulation requirements [2,28–33]. Nevertheless, very few international 110 studies have included therewith an important factor to consider in comparing different 111 building materials: how constructive solution will be installed [34,35]. These installation 112 parameters are defined by the constructive system itself as well as the type and 113 amount of material to place [36–38]. The amount of material to be installed will be also 114 determined by the climatic conditions at the building location. So as has been noted 115 above, any factor that influences the amount of insulating material should be included 116 in their environmental assessments. Additionally, to our knowledge, no published 117 information relating the effect of climatic conditions on optimum combination of façade- 118 building systems and thermal insulation materials. 119 This paper can help to fill this gap and provide a detailed environmental impact 120 assessment comparing different constructive systems in Spanish context, where exist 121 different climate zones with diverse climatic conditions. Hence the desirability of either 122 insulation material will be very different. The novelty of the paper also consists in the 123 inclusion of the installation phase in the environmental assessment of thermal 124 insulation materials, which are applied in different façade-building systems. 125 2. Materials and methods 126 2.1. Objectives 127 This article determines the best environmental alternative for the thermal insulation of a 128 building façade located in Spain and evaluates the environmental impact of the most 129 common types of façade systems. The specific objectives are: 130 · To elaborate an inventory of the materials, machinery and energy consumption in the 131 production, transport and installation phases of the life cycle of the façade solutions 132 analysed. 4 133 · To assess the environmental impact of the different façade systems considering 134 different insulation materials to determine what the less impactful constructive 135 alternatives are under the climate conditions established. 136 · To compare the environmental impact of different insulation materials in each façade 137 systems according to different climate zones established in Spain. 138 2.2. Insulation materials under study 139 The European market of insulation materials is still dominated by two groups of 140 products. On the one hand the inorganic fibrous materials account for 60% of the 141 market, primarily Mineral wool (MW) and Stone wool (SW). On the other hand the 142 organic foamy materials account for about 30% of the market, the most common are 143 expanded polystyrene (EPS), extruded polystyrene (XPS) and the less widespread 144 polyurethane (PU) [25,30]. All other materials accounted for less than 13% together, 145 among them: Insulation cork board (ICB), Wood wool, Aerogel, etc. These materials 146 have been encouraged as efficient insulation and as sustainable solutions. But, few 147 studies have been published about these alternative materials [2,28,39–43]. In 148 summary, this study considers the environmental assessment of the most common 149 materials: MW, SW, EPS, XPS and PU, representing 90% of the worldwide market. 150 2.3. Description of the façade systems under study 151 This section illustrates in detail the structural features of the various façade systems 152 included in the study (Fig. 1). Also the process of construction and the installation of 153 the components are described [38,44]. 154 155 5 156 2.3.1. External Thermal Insulation Composite Systems (ETICS) 157 ETICS is a constructive solution for façade composed by multiple layers: the wall, the 158 insulation material, the fixing on the substrate, the reinforcing intermediate coating and 159 reinforcement mesh and a decorative finish coating. The objective of ETICS is to 160 minimize the heat bridges and losses and to remain reliable and durable protecting the 161 building against environmental and climatic factors. The system has to have high 162 resistance to mechanical stress, impermeability to water and permeability to CO2 and 163 to water vapor. Insulation boards are fixed on the wall with adhesive mortar and/or 164 dish-shaped dowels depends on the quantity and type of insulation and the type of 165 substrate. 166 2.3.2. Ventilated façade 167 The Ventilated façade is a system consisting of a multi-layered building envelope which 168 an outer layer made of different materials (metal, stone, wood facade boards (bars), 169 composite, ceramic granite, etc.) is mechanically connected with galvanized steel, 170 stainless steel or aluminum frame to the inner layer. This inner layer is insulated from 171 de outside with board or foam insulation and is attached with adhesive mortar and/or 172 dish-shaped dowels, depends on the thickness and type of insulation. The ventilated 173 façade allows free air circulation intermediate cavity that removes moisture and under 174 the effect of the solar radiation, the energy performance of these façade systems 175 improves in relation to conventional façades. Furthermore, the installation of the 176 insulation material outside the main wall eliminates thermal bridges, i.e. a localised 177 area of the building envelope where the heat flow is different (usually increased) in 178 comparison with adjacent areas. 179 2.3.3. Internal insulation façade 180 The Internal insulation façade is a constructive solution of enclosure composed of outer 181 main wall, insulation and inner cladding. The insulation layer is fixed with metallic 182 profiles which are mechanically connected to the floor and ceiling. This system is the 183 most usual for the construction of facades of new buildings and rehabilitation of existing 184 buildings. The inner insulation separates the thermal mass of the walls of the living 185 space and reduces both the response time and the energy required to achieve thermal 186 comfort. It is one of the cheaper options but must take into account the interruption of 187 insulation in the ceilings and walls encounters, so they can produce thermal bridge. 188 2.4. Climate considerations in the selection of façade systems 189 Considering the climate zone where the facade is located, it should take into account a 190 several factors that can influence the performance of each of the solutions. The most 191 important are: 192 1) Solar radiation that supports the façade. 193 2) The thermal inertia of the whole façade. 194 3) The evacuation of the possible condensation produced. 6 195 For the first parameter, the facades located in warm zones will have more impact from 196 sunlight; with high outside temperatures. For that, the ventilated facades prevents heat 197 can enter into the building, keeping comfort temperatures in summer. In the case of 198 ETICS, the color of the external coating avoids influence heat transfer, for example the 199 white color will reflect the sunlight. In the case of the thermal inertia, it will influence 200 climates where there are marked temperature changes between day and night. 201 Therefore, the ceramic block, used in ETICS as internal wall, allows the maintenance 202 of the temperature within the building although the outer conditions change throughout 203 the day. Moreover, the rain or the temperature changes can cause the condensation of 204 water vapor. In that case, ETICS is the least indicated in the wetlands, either by rain or 205 coastal areas, since the outer coating is more easily degrade and need to add 206 maintenance actions. To facilitate the evacuation of condensation water, different 207 solutions included in the Internal insulation façade and Ventilated façade systems are 208 recommended. 209 2.5. Declared unit 210 The declared unit (DU) is used instead of the functional unit when the precise function 211 of the product or building-level scenarios is not stated or unknown. In this case, to 212 insulate a given surface of a building façade, the amount of insulation material required 213 will vary depending on the type of constructive solution or the geographic location of 214 the building, among others. It has been established a DU according to the 215 environmental product declaration (EDP) for construction products EN 15804:2014 [45] 216 in order to compare the environmental impacts of the constructive solutions under 217 study on the basis of the different insulation materials. 218 The DU is the production, transport and installation of the necessary quantity of 219 materials to construct 1m2 of three façade solutions selected: 1) ETICS, 2) Ventilated 220 façade and 3) Internal insulated façade. And as noted above, the commonly used 221 insulation materials in building have been selected for the study: EPS, XPS, PU, MW 222 and SW. In order to establish the adequate quantity of each insulation material, the DU 223 must be related with the heat transferred through it [28,46,47], using the following 224 equation to calculate the amount of insulation required: 𝐷𝑈 = 𝑅𝜆𝜌𝐴 (1) 225 Where R represents the thermal resistance (m2K/W), a heat property and a 226 measurement of a temperature difference by which a material resists a heat flow. The 227 greater the R value is more insulation material. In addition the inverse of R is used; it is 228 called thermal transmittance (U). The factor 𝜆 is the thermal conductivity (W/m K), the 229 most important property of any thermal insulation material, i.e. the low capacity of a 230 substance to transport thermal energy [48]. ρ corresponds to the density of the material 231 (kg/m3), it can be showed in Table 2. And A is the surface of façade (m2), in this case 232 the value is 1m2. Consequently, in the calculations required in order to decide the 233 adequate quantity of the insulation material, it has been established a thermal 234 transmittance value U=0.27 (W/m² K) or R=3.7 (m2K/W) to insulate façades over the 235 course of 50 years (Table 2). These value is according to the parameters required by 236 the Spanish Technical Building Code for a building located in a “D” climate zone, the 237 largest climate zone in Spain [37]. 7 XPS EPS PU MW SW Thermal conductivity (λ) (W/m K) 0.032 0.035 0.023 0.039 0.036 3 Density (kg/m ) 20 35 31 130 21.8 Thickness (m) 0.10 0.11 0.07 0.13 0.12 ETICS Weight (Kg) 2.06 3.95 2.30 16.35 2.53 Thickness (m) 0.10 0.11 0.07 0.12 0.11 Ventilated façade Weight (Kg) 2.0 3.8 2.2 15.8 2.5 Internal insulation Thickness (m) 0.11 0.12 0.08 0.13 0.12 façade Weight (Kg) 2.2 4.2 2.5 17.5 2.7 238 Table 2. Functional unit (kg) required of insulation per façade solution 239 to provide a thermal resistance in “D” climate zone 240 Additionally, a sensitivity analysis focused in the location of the building has been 241 performed. In Spain several climate zones have defined. The determination of climatic 242 zones is obtained from the calculation of climatic severities of winter and summer as 243 recorded contrasting localities, through the combination of the parameters degree days 244 and solar radiation in the locality. Therefore the requirements of insulation are different, 245 i.e. the data for thermal transmittance (U) for each climate zone change, that is, the 246 insulation thickness. Table 3 shows the insulation required in each climate zone per 247 type of façade system, being “α” the warmest climate zone and “E” the coldest. XPS EPS PU MW SW Thermal conductivity (λ) (W/m K) 0.032 0.035 0.023 0.039 0.036 Density (kg/m3) 20 35 31 130 21.8 U-value Thickness (m) Climate α 0.94 0.02 0.02 0.01 0.02 0.02 Climate A 0.5 0.05 0.05 0.03 0.06 0.05 ETICS Climate B 0.38 0.07 0.07 0.05 0.08 0.08 Climate C 0.29 0.09 0.1 0.07 0.11 0.11 Climate E 0.25 0.11 0.12 0.08 0.13 0.12 Climate α 0.94 0.01 0.02 0.01 0.02 0.02 Climate A 0.5 0.04 0.05 0.03 0.05 0.05 Ventilated Climate B 0.38 0.06 0.07 0.05 0 .08 0.07 façade Climate C 0.29 0.09 0.1 0.07 0.11 0.1 Climate E 0.25 0.11 0.12 0.08 0.13 0.12 Climate α 0.94 0.02 0.02 0.01 0.02 0.02 Internal Climate A 0.5 0.05 0.06 0.04 0.06 0.06 insulation Climate B 0.38 0.07 0.08 0.05 0.09 0.08 façade Climate C 0.29 0.1 0.11 0.07 0.12 0.11 Climate E 0.25 0.12 0.13 0.09 0.14 0.13 248 Table 3. Functional unit (m) required of insulation per façade solution 249 to provide a thermal resistance in the climate zones established in Spain 250 2.6. Methodology 251 The LCA methodology is used in this paper, from a cradle to site approach, which 252 means that environmental impacts analysis includes the production (extraction and 253 processing of raw materials, transport to manufacturer and manufacturing), transport to 8 254 the building site and the installation in the building (Figure 2). The software Simapro 7.3 255 has been used [49]. 256 257 2.6.1. Impact categories 258 According to the European standard that provides the core product category rules for 259 all construction products and services, EN 15804:2014 [45], the following seven 260 midpoint impact categories from the CML 2 baseline 2002 [50] were included in the 261 assessment: abiotic depletion potential (ADP), acidification potential (AP), 262 eutrophication potential (EP), global warming potential (GWP), ozone layer depletion 263 (OLDP) and photochemical oxidation (PCOP). Additionally, as appointed above, the 264 embodied energy (EE) or the cumulative energy demand (CED) has been included due 265 to the increasing importance in the building energy demand. 266 2.6.2. Environmental impact assessment of the constructive solutions 267 The assessment of the façade systems requires data about the materials and quantity 268 of the insulation, as well as installation data. According to the established DU and the 269 building technical considerations, the Supplementary data indicates the materials and 270 energy content for 1m2 of the various façade systems. 271 For the installation phase, the materials and energy for the assembly of all components 272 were considered. In the case of the insulation, different solutions for fixing exist: first 273 depends on the façade system and second according the type of insulation materials 274 and its thickness. The thickness depends on the climate conditions, and therefore the 275 climatic zone where the building is located. In the case of ETICS and Ventilated 276 façade, the insulation board is attached in the outside in all the climate zones. It has to 277 be fixed with adhesive mortar for XPS and EPS and for thickness less than 40 mm. 278 The dish-shaped dowels are used for PU, MW and SW and for XPS and EPS boards 279 with a thickness greater than 40 mm. In the case of the “D” climate zone, all the 280 insulation materials thickness are greater than 40 mm, so all are fixed with the same 281 elements: adhesive mortar and dish-shaped dowels. Also for Ventilated façade the 282 fixation of insulation is made with the metals profiles that hold the external cladding. In 283 the case of the Internal insulated façade the same fixation solution is used for all 9 284 materials, thicknesses and climate zones: a structure made of metallic profiles attached 285 to the ceiling and the floor and where the insulation boards are fitted. 286 2.7. Data sources 287 Different sources of information were used in the process of collecting data for the 288 inventory, Table 4 summarizes them. Source Data obtained Reference CSIC, 2008 Constructive description and dimensions [36] per façade solution Ministerio de Vivienda, Thermal parameters for calculations [37] 2013 Metabase Itec, 2010 Quantity of materials (kg/m2 of façade) [51] Diesel consumption (MJ/h) and working hours (h) for machinery Ecoinvent 3.1 database Environmental impacts of materials [52] extraction Table 4. Summary of the data obtained from each data source 289 In order to determine the transport distance of each of the materials used in the 290 construction, previous studies were consulted [32,53,54]. Finally, a distance of 100 km 291 was assumed for all materials, due to their abundance, long distances are not 292 common. 293 All the environmental information is taken from the same database, allowing the 294 comparability of the different façade solutions and insulation materials. The database 295 used to obtain the environmental information related with the processes involved with 296 materials, energy and transport is ecoinvent 3.1 database [52]. 297 3. Results and discussion 298 3.1. Comparison of the environmental impact of the different façade solutions 299 The life cycle impacts of 1m2 of the various façade systems are presented in absolute 300 values in Figure 3 and are disaggregated in following sections. 10 301 302 A comparison of the constructive solutions for façades reveals differences between the 303 environmental impacts derived from each solution and also due to the insulation 304 material used. Related to the constructive solutions, the Ventilated façade has the 305 greatest impacts in most categories, except in AP and PCOP, on which the Internal 306 Insulation Façade has greater impacts 6% and 13%, respectively. ETICS has the 307 lowest value in the most of categories, except for EP, GWP and OLDP, on which has 308 similar values that Internal Insulation façade. The Ventilated façade system is a more 309 complex construction solution than ETICS and Internal insulation façade, due to its 310 better performance in energy efficiency during the use of building. In the case of EE 11 311 category, there are important differences between façade systems, especially the 312 ventilated facade with respect to other facade systems. The results for Ventilated 313 façade are 30-70% greater than ETICS results and 15-40% greater than Internal 314 insulation façade. The desirability of designing buildings with a particular type of facade 315 will be analyzed in future studies which include how efficient are each façade system in 316 the use phase of the building. 317 3.1.1. Environmental impacts of production phase 318 With regard to the disaggregated data by phase of the life cycle, in the case of ETICS 319 and Ventilated façade the greatest impacts are concentrated in the production phase, 320 accounting for 60-90% of global impact (Figure 3). As noted above, the Ventilated 321 façade system is most complex than ETICS and Internal insulation façade systems. 322 For that, in environmental terms, it is the façade system with largest impacts in 323 production phase. But on the other hand, its performance during the use is better than 324 others. In the case of ETICS, their construction system is not so complex, but the other 325 life cycle phases not represent significant impacts. For the Internal insulation façade, 326 the production phase accounts for between 20-70% of total impacts. Its constructive 327 solution is very simple, containing few processes and materials associated with this 328 phase. 329 3.1.2. Environmental impacts of transport phase 330 For the transport phase, the differences between the alternatives by type of 331 constructive solution are related with the amount of material to construct 1m2 of façade 332 for each constructive system. Moreover, depends on the insulation material used, 333 different quantity will be required for each alternative. Therefore the rest of material 334 required is the same for each facade systems and, for that; the differences in the 335 impact are derived from the production phase. 336 3.1.3. Environmental impacts of installation phase 337 It can be noted that the values used in the installation for each facade systems are the 338 same in all the insulation alternatives as they are within the same climate zone. The 339 insulating panels required in ETICS and Ventilated façade overcome the 400 mm of 340 thickness; for that, they have to be fixed with dish-shaped dowels. For Internal 341 insulation façade, the installation phase produces a great part of environmental impact 342 in most of alternative insulation materials, reaching in several alternatives more than 343 70% of global impact. This phase exceeds the values of the production phase in all the 344 SW impact categories and for the rest of insulation materials in AP, EP y OLDP and 345 PCOP. This may be due to two reasons: 1) the constructive solution is very simple 346 itself, so the production phase contains fewer processes and materials and hence is 347 less relevant; and 2) the system used to fix the insulation boards are made from 348 metallic material (aluminum profiles), which have a significant environmental impact. 349 So an opportunity for environmental improvement is observed, either replacing the 350 material profiles of fixation by a less impacting materials or developing a fixation 351 system that requires less material. 352 The environmental impacts of transport and installation phase represent between 10- 353 30% of the environmental impact in all categories. These impacts, according to the 12 354 insulation material used, are greater the better environmental performance is the 355 insulation material. This is due to the production phase is less relevant, in 356 environmental terms, and so increase the importance of the other phases. Thus, the 357 reduction of these environmental impacts involves the optimization of the process of 358 installation, using simpler and less impacting material systems. Moreover, it should to 359 optimize the quantity of insulation material used without committing the thermal 360 requirements of the building. 361 362 3.2. Environmental impact of the different insulation materials 363 Previously, it has been noted the importance of the production phase for all the 364 construction systems. Moreover, also is observed the influence of the insulation 365 materials in the environmental behaviour of the façade systems. Table 5 shows the 366 relation between the different insulation material impacts and the global impacts of the 367 façade systems under study. It can be observed that the insulation material that 368 contributes the most to the environmental impact is MW. More than 30% in the most of 13 369 categories for all façade systems, and even for some categories its contribution 370 exceeds 50% of the global impact (EP, PCOP and EE). The least impacting insulation 371 material is SW, which contributions are between 4 and 14% of global impact for all 372 categories and façade systems. Moreover, Table 5 shows the differences between the 373 environmental performances of each insulation material in each constructive solution. 374 This is due to the differences in the structure of the façade systems, varying the 375 amount and type of materials that form. For that, insulation materials will have more 376 importance on environmental performance in the simplest systems construction; e.g. 377 ETICS and Internal insulation façade. ETICS Ventilated façade Internal insulation façade XPS EPS PU MW SW XPS EPS PU MW SW XPS EPS PU MW SW ADP (kg Sb eq) 8.8E-02 1.6E-01 9.9E-02 1.9E-01 2.4E-02 2.1E-01 1.5E-01 9.6E-02 1.8E-01 2.3E-02 9.4E-02 1.7E-01 1.1E-01 2.0E-01 2.6E-02 AP 2.8E-02 2.8E-02 1.9E-01 1.6E-01 3.0E-02 2.8E-02 4.2E-02 4.1E-02 1.5E-01 2.9E-02 3.0E-02 4.6E-02 4.6E-02 1.7E-01 3.2E-02 (kg SO2 eq) EP 1.6E-02 2.3E-02 2.6E-02 2.2E-01 1.6E-02 1.5E-02 2.2E-02 2.5E-02 2.1E-01 1.6E-02 1.7E-02 2.5E-02 2.7E-02 2.3E-01 2.3E-01 (kg PO4--- eq) GWP 8.0E+00 1.3E+01 1.0E+01 2.0E+01 3.7E+00 7.7E+00 1.3E+01 9.7E+00 1.9E+01 3.6E+00 8.5E+00 1.4E+01 1.1E+01 2.1E+01 3.9E+00 (kg CO2 eq) OLDP 4.3E-07 6.4E-07 1.0E-07 2.9E-06 2.8E-07 4.2E-07 6.2E-07 1.0E-07 2.9E-06 2.7E-07 4.6E-07 6.8E-07 1.1E-07 3.2E-06 3.0E-07 (kg CFC-11 eq) PCOP 2.6E-03 2.7E-03 3.2E-03 6.5E-03 8.7E-04 2.6E-03 2.6E-03 3.1E-03 6.3E-03 8.5E-04 2.8E-03 2.9E-03 3.4E-03 6.9E-03 9.3E-04 (kg C2H4 eq) EE 2.0E+02 3.5E+02 2.3E+02 7.1E+02 4.9E+01 2.0E+02 3.4E+02 2.3E+02 6.9E+02 4.8E+01 2.2E+02 3.8E+02 2.5E+02 7.6E+02 5.3E+01 (MJ) >50% 30-50% 10-30% <10% of the of the of the of the global global global global impact impact impact impact 378 379 Table 5. Relation between the environmental impacts of the insulation materials 380 and the global impacts of the façade systems 381 MW presents the highest environmental impacts in all categories and an impact up to 2 382 times greater than all the insulation material for almost all the categories (except ADP 383 and GWP). The second most impacting material is EPS but its environmental impacts 384 are far from MW results, between a 15 to 90% lower impact than MW. XPS and PU 385 have similar results in almost all the categories, between a 10 to 50% lower impact 386 than MW. 387 3.3. Environmental impacts according to the climate zone 388 As pointed above, a sensitivity analysis focused in the location of the building has been 389 performed in terms of GWP and EE. Figure 5 shows differences between the impacts 390 generated by each type of building facades depending on the area where the building 391 is constructed. Looking at the data for the warmer zone, the α zone, the Ventilated 392 facades are the systems which generate more impacts, both GWP and EE. ETICS and 393 Internal insulation façade are the less impacting systems, with similar values in terms 394 of GWP. But if we attend at the EE data, ETICS is the system with the lowest energy 395 contained. As the climate zone is colder, the environmental behaviour patterns are not 396 uniform within a constructive solution. It is noted a trend in which the critical parameter 397 is the type of insulating material used; this issue will be discussed in the next section. 14 398 399 If we focus on the type of facade system by type of climatic zone, the most 400 recommended one from an environmental approach for warmer zones is ETICS. 401 Although in coastal areas, as noted above, the outside coating of ETICS will need 402 maintenance due to these adverse conditions. From a technical point of view, the 403 ventilated facade would be the most recommended, despite of having a higher 404 percentage of impact. For colder climates, the most advisable solution facade would be 405 ETICS, in terms of EE, depending on the selected insulating material. Although one 406 should be analyzed the climatic conditions of humidity, considering the maintenance 407 that should suffer this type of façade in the future. The interest of construct this type of 408 façade should be analyzed more extensively including the use phase in future studies. 409 Regarding to the insulation materials, if we consider the geographical location of the 410 building, the parameter of the weather has to be taken into account. For that, the 411 thermal insulation needs will vary the quantity of insulation materials required in each 412 climate zones. As colder is the location of the building largest amount of insulation will 413 be necessary, therefore greater environmental impact. This will increase the influence 414 of insulation on the overall impact in all the façade systems. The influence of this 415 parameter is shown in Table 6, in terms of GWP and EE, for the climate zones defined 416 in Spain. 417 In terms of GWP, it can be observed a marked increase in the importance of thermal 418 insulation according cooler is the area under study. The most advisable material is the 419 SW, which has impact values lower than 10% for all facade systems in all climatic 420 zones. Also XPS and PU have lower values of 10% in the α and A zones. In terms of 421 EE, insulation has a great importance in systems building facades. Some of the 422 materials under study exceed in most climate zones of more than 20% of the total 15 423 embodied energy of the façade system. In coldest zones (zones C, D and E), the 424 combination of ETICS and Internal façade insulation with EPS, PU and MW materials 425 account for over 30% of global impact. On the other hand the SW material has a lower 426 impact than 10% of the overall impact in all façade systems and in all climatic zones. 427 Meanwhile, in the case of Ventilated façade all the insulation materials have the lowest 428 percentages of total impacts in each climate zone. Although as discussed above the 429 components of this constructive system has a global impact greater than other façade 430 systems. GWP (kg CO2 eq.) EE (MJ) XPS EPS PU MW SW XPS EPS PU MW SW ETICS 1.3E+00 2.3E+00 1.7E+00 3.4E+00 6.2E-01 3.4E+01 6.0E+01 4.0E+01 1.2E+02 8.3E+00 Clima α Ventilated 1.1E+00 1.9E+00 1.4E+00 2.8E+00 5.2E-01 2.9E+01 5.0E+01 3.3E+01 1.0E+02 6.9E+00 Internal 1.8E+00 2.2E+00 1.6E+00 3.3E+00 6.0E-01 4.5E+01 5.8E+01 3.8E+01 1.2E+02 8.0E+00 ETICS 3.7E+00 6.2E+00 4.6E+00 9.3E+00 1.7E+00 9.4E+01 1.6E+02 1.1E+02 3.3E+02 2.3E+01 Clima A Ventilated 3.4E+00 5.8E+00 4.3E+00 8.6E+00 1.6E+00 8.7E+01 1.5E+02 1.0E+02 3.1E+02 2.1E+01 Internal 4.1E+00 6.8E+00 5.1E+00 1.0E+01 1.9E+00 1.0E+02 1.8E+02 1.2E+02 3.6E+02 2.5E+01 ETICS 5.3E+00 8.8E+00 6.6E+00 1.3E+01 2.4E+00 1.3E+02 2.3E+02 1.5E+02 4.7E+02 3.2E+01 Clima B Ventilated 5.0E+00 8.3E+00 6.2E+00 1.2E+01 2.3E+00 1.3E+02 2.2E+02 1.5E+02 4.4E+02 3.0E+01 Internal 5.6E+00 9.4E+00 7.0E+00 1.4E+01 2.6E+00 1.4E+02 2.5E+02 1.7E+02 5.0E+02 3.5E+01 ETICS 7.3E+00 1.2E+01 9.1E+00 1.8E+01 3.4E+00 1.9E+02 3.2E+02 2.1E+02 6.5E+02 4.5E+01 Clima C Ventilated 7.1E+00 1.2E+01 8.8E+00 1.8E+01 3.3E+00 1.8E+02 3.1E+02 2.1E+02 6.3E+02 4.4E+01 Internal 7.7E+00 1.3E+01 9.7E+00 1.9E+01 3.6E+00 2.0E+02 3.4E+02 2.3E+02 6.9E+02 4.8E+01 ETICS 8.0E+00 1.3E+01 1.0E+01 2.0E+01 3.7E+00 2.0E+02 3.5E+02 2.3E+02 7.1E+02 4.9E+01 Clima D Ventilated 7.7E+00 1.3E+01 9.7E+00 1.9E+01 3.6E+00 2.0E+02 3.4E+02 2.3E+02 6.9E+02 4.8E+01 Internal 8.5E+00 1.4E+01 1.1E+01 2.1E+01 3.9E+00 2.2E+02 3.8E+02 2.5E+02 7.6E+02 5.3E+01 ETICS 8.5E+00 1.4E+01 1.1E+01 2.1E+01 3.9E+00 2.2E+02 3.8E+02 2.5E+02 7.6E+02 5.3E+01 Clima E Ventilated 8.3E+00 1.4E+01 1.0E+01 2.1E+01 3.8E+00 2.1E+02 3.7E+02 2.4E+02 7.3E+02 5.1E+01 Internal 9.2E+00 1.5E+01 1.1E+01 2.3E+01 4.2E+00 2.3E+02 4.1E+02 2.7E+02 8.1E+02 5.6E+01 >30% of the global impact 20-30% of the global impact 10-20% of the global impact <10% of the global impact 431 Table 6. Comparison of the environmental impacts of insulation materials in different façade systems 432 located in the various climate zones defined in Spain 433 In Figure 5, it can be compared the different combination between façade systems and 434 insulation material according to climatic zone. In the warmest zones, the choice of the 435 insulation material has a lower influence in the environmental performance of the whole 436 façade. This is because the lower insulation requirements, and therefore the type of 437 façade have the greatest influence. The importance in the choice of insulating material 438 increases as the temperature zone is cooler. The combination of ventilated facade with 439 MW is the most impacting to all climatic zones in terms GWP and EE. Moreover, the 440 combination of Internal insulation façade with SW is the least impacting in GWP terms, 441 and the combination of ETICS with SW in EE terms. As can be observed, all the 442 combinations with SW have the least environmental impact with increasing need for 443 thermal insulation. On the other hand, MW presents the greatest increases for all the 444 façade systems. In EE terms, it can be noted that the most impacting combination 16 445 triples the least. For that, it can be pointed the importance of the choice of the type of 446 façade system and insulation material, depending on the climate zone where the 447 building is located. 448 4. Conclusions 449 The results show that the most impacting alternative of façade is the Ventilated façade 450 in combination with the insulation materials with highest environmental impacts: MW 451 and EPS. MW represents between 30-50% of the global impacts in the most of 452 categories for all façade systems, and EPS between a 15 to 90% lower impact than 453 MW. On the other hand SW presents the lowest environmental impacts in almost all 454 the categories between an 80 to 95% lower impact than MW. This behaviour is 455 determined by the physical and insulation properties of different materials, but also the 456 environmental performance of them. Insulation materials are an important part in the 457 environmental impacts of the production phase, which in turn represents the most 458 impacting phase for ETICS and Ventilated façade. So it can be noted the relevance of 459 the choice of the insulation. 460 The whole constructive solution where the insulation materials are installed must be 461 considered in order to not omit the environmental impacts of the materials transport 462 and installation phases. In the case of ETICS and Ventilated façade can represent 463 between 10-30% of the global environmental impact in all categories. The installation 464 phase is especially relevant for Internal insulation façade, where the environmental 465 impacts accounts for between 30-90% for all categories. The environmental impacts of 466 transport and installation phase according to the insulation material used are greater 467 the better environmental performance is the insulation material. This is due to the 468 production phase is less relevant, in environmental terms, and so increase the 469 importance of the other phases. Thus, the reduction of these environmental impacts 470 involves the optimization of the process of installation, using simpler and less impacting 471 material systems. Moreover, it should optimize the quantity of insulation material used 472 without committing the thermal requirements of the building. 473 In addition, if the climate conditions where the building is located within Spain are taken 474 into account, the thermal and construction requirements change, and therefore the 475 need for insulation and the suitability of a particular facade system. In warm zones, the 476 most recommended façade system is ETICS, especially in terms of embodied energy. 477 Although in coastal areas, as noted above, the outside coating of ETICS will need 478 maintenance due to these adverse conditions. From a technical point of view, the 479 ventilated facade would be the most recommended, despite of having important 480 environmental impacts. For colder climates, the most advisable solution facade would 481 be ETICS, in terms of EE, depending on the selected insulating material. Although one 482 should be analyzed the climatic conditions of humidity, considering the maintenance 483 that should suffer this type of façade in the future. In the particular case of Spain, due 484 to its aging housing park, it should extend this study to the case of rehabilitation. 485 Therefore, it could be analysed how the impact generated in rehabilitation is 486 compensated due to improved insulation of the façade. 487 The methodology proposed can be applied to any constructive solution as well as to 488 more complex systems as a whole building. This methodology allows property 17 489 developers, architects and urban planners, to calculate the environmental impacts 490 derived from the building construction, which is useful for decision making during the 491 design of the building. In future studies the use phase of the building will be taken into 492 account in order to include the energy needs for heating or cooling the inside. 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