External Thermal Insulation Composite Systems (ETICS): An Evaluation of Hygrothermal Behaviour PDF
Preview External Thermal Insulation Composite Systems (ETICS): An Evaluation of Hygrothermal Behaviour
SPRINGER BRIEFS IN APPLIED SCIENCES AND TECHNOLOGY Eva Barreira Vasco Peixoto de Freitas External Thermal Insulation Composite Systems (ETICS) An Evaluation of Hygrothermal Behaviour 123 SpringerBriefs in Applied Sciences and Technology More information about this series at http://www.springer.com/series/8884 Eva Barreira · Vasco Peixoto de Freitas External Thermal Insulation Composite Systems (ETICS) An Evaluation of Hygrothermal Behaviour 1 3 Eva Barreira Vasco Peixoto de Freitas Department of Civil Engineering Department of Civil Engineering Faculty of Engineering Faculty of Engineering University of Porto University of Porto Porto Porto Portugal Portugal ISSN 2191-530X ISSN 2191-5318 (electronic) SpringerBriefs in Applied Sciences and Technology ISBN 978-3-319-20381-2 ISBN 978-3-319-20382-9 (eBook) DOI 10.1007/978-3-319-20382-9 Library of Congress Control Number: 2015949448 Springer Cham Heidelberg New York Dordrecht London © The Author(s) 2016 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper Springer International Publishing AG Switzerland is part of Springer Science+Business Media (www.springer.com) Preface External Thermal Insulation Composite Systems—ETICS are nowadays often used in Europe. Despite its thermal advantages, low cost and ease of application, this system has serious problems of biological growth, causing the cladding deface- ment. Although no changes occur in the thermal and mechanical performance of the system, biological defacement has an enormous aesthetic impact, which gath- ers the building’s dwellers’ disapproval, thus restricting full implementation of this technology. The most important goal of this publication is to assess the hygrothermal behaviour of façades covered with ETICS as the main cause of biological growth and present a methodology to estimate the risk of defacement that can be used as a decision support tool. Its special features are: (a) 1-year experimental test cam- paign results; (b) methodology to assess the hygrothermal behaviour; (c) sensi- tivity analysis of hygrothermal behaviour based on numerical simulation and (d) evaluation of obstacles influence. The main benefit of this book is to compile information on ETICS hygrother- mal behaviour, as almost no information is available on this topic. It will also add new findings achieved by the authors and will highlight key aspects to be con- sidered when applying ETICS, for practitioners, or when studying hygrothermal behaviour of ETICS, for researchers or students. It will also provide a decision support tool for avoiding undesired hygrothermal behaviour, which may be very interesting for those who intend to apply the system. The authors would like to acknowledge their gratitude for the support received from the University of Porto—Faculty of Engineering, Portugal, and from the Building Physics Laboratory (LFC). Finally, the authors would welcome read- ers’ comments, corrections and suggestions with the aim of improving any future editions. Eva Barreira Vasco Peixoto de Freitas v Contents 1 Introduction ................................................ 1 1.1 Motivation ............................................. 1 1.2 General Characteristics and Main Advantages of ETICS ......... 2 1.3 Common Pathologies on ETICS ............................ 3 References .................................................. 6 2 Experimental Studies on Hygrothermal Behaviour of ETICS ....... 9 2.1 Setting up the Test ....................................... 9 2.1.1 Preliminary Tests .................................. 9 2.1.2 One-Year in Situ Tests .............................. 12 2.2 Results ................................................ 14 2.2.1 Surface Temperature ................................ 14 2.2.2 Exterior Surface Condensation ........................ 17 2.2.3 Wind-Driven Rain ................................. 18 2.2.4 Surface Moisture .................................. 19 2.3 Discussion of the Results .................................. 20 References .................................................. 21 3 Assessment of ETICS’ Surface Humidification ................... 23 3.1 Validation of the HAM Numerical Model ..................... 23 3.1.1 The Hygrothermal Model ............................ 23 3.1.2 Comparison Between Simulated and Measured Values ..... 25 3.2 Humidification Model BIO.MOD ........................... 28 3.2.1 General Comments ................................. 28 3.2.2 Assessing the Exterior Surface Condensation ............ 29 3.2.3 Assessing the Wind-Driven Rain ...................... 29 3.2.4 Assessing the Drying Process. . . . . . . . . . . . . . . . . . . . . . . . . 30 3.2.5 Assessing Surface Humidification–BIO.MOD Indices ..... 30 3.2.6 Validation of BIO.MOD Indices ...................... 31 References .................................................. 32 vii viii Contents 4 BIO.MOD Indices Application Examples ........................ 35 4.1 Risk Map of ETICS Surface Humidification—The Portuguese Case ....................... 35 4.2 Critical Parameters Involved in ETICS Surface Humidification .... 36 References .................................................. 44 5 Experimental and Numerical Study on the Effect of Nearby Obstacles in Surface Condensations on ETICS .......... 47 5.1 Experimental Study ...................................... 47 5.1.1 Setting up the Test ................................. 47 5.1.2 Results .......................................... 49 5.1.3 Discussion of the Results ............................ 57 5.2 Numerical Model to Simulate the Influence of Nearby Obstacles ... 58 5.2.1 Numerical Model MOD.O ........................... 58 5.2.2 Vertical Obstacles .................................. 58 5.2.3 Horizontal Obstacles ............................... 59 5.3 Validation of the Model ................................... 60 5.3.1 Parameters for the Simulation ........................ 60 5.3.2 Vertical Obstacles .................................. 60 5.3.3 Horizontal Obstacles ............................... 63 5.3.4 Discussion of the Results ............................ 64 5.4 Practical Application of the Model ........................... 65 References .................................................. 67 6 Conclusions and Recommendations ............................ 69 Symbols and Units BIO.MOD1 Humidification index related with condensation (–) BIO.MOD2 Humidification index related with rain (–) BIO.MOD3 Humidification index related with condensation and rain (–) CP Condensation Potential (Pa) CPd Condensation Potential in degrees (°C) CPE Condensation Potential Equivalent (Pa h) CPEd Condensation Potential Equivalent in degrees (°C h) D Liquid conduction coefficient (kg/m s) φ DP Drying Potential (Pa) DPE Drying Potential Equivalent (Pa h) F Atmospheric field of view (–) atm F View factor between the horizontal obstacle and the surface (–) HO F View factor between the vertical obstacle and the surface (–) VO F Field of view of the ground (–) ter h Distance between the vertical obstacle and the surface (m) h Horizontal obstacle depth (m) h Evaporation enthalpy of the water (J/kg) v I Long wave radiation emitted by the surface (W/m2) e I Long wave radiation arriving to the surface (W/m2) l I Downward atmospheric radiation (W/m2) atm I Long wave radiation emitted by the ground (W/m2) ter I Solar radiation arriving to the surface (W/m2) s I Diffuse solar radiation normal to the surface (W/m2) s,dif I Direct solar radiation normal to the surface (W/m2) s,dir I Vertical obstacle radiation that reaches the façade (W/m2) VO(inc) I Solar radiation reflected by the ground (W/m2) s,ref p Water vapour saturation pressure (Pa) sat P (surface) Water vapour saturation pressure on the surface (Pa) sat P(air) Water vapour partial pressure in the air (Pa) v R Horizontal rainfall amount (mm/h) h ix x Symbols and Units R, R Driving rain coefficients 1 2 T Temperature (K) T Dew point temperature (°C) dp T Surface temperature (°C) s T Surface temperature (K) surf v Wind speed (m/s) wind v Reference wind speed at 10 m above ground (m/s) 10 w Moisture content (kg/m3) w Width of the obstacle (m) w Façade height (m) WDR Wind-driven rain intensity (mm/h) WDRPE WDR Potential Equivalent (Pa h) Greek Letters α Convective heat transfer coefficient (W/m2 K) c α Short wave absorptance (–) s β Moisture transfer coefficient (m/s) δ Water vapour permeability (kg/m s Pa) p ε Long wave emissivity (–) θ Angle between the wind direction and the normal to the façade (º) λ Thermal conductivity (W/m K) ρ Long wave radiation reflectivity of the ground (–) ter σ Stefan–Boltzmann constant (5,67 10–8 W/(m2 K4)) × φ Inclination of the surface (º) φ Relative humidity (%)
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