Performance Modelling of Timber Facade Elements

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(1)Performance Modelling of Timber Fa¸ cade Elements.

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(3) Performance Modelling of Timber Fa¸ cade Elements. PROEFSCHRIFT ter verkrijging van de graad van doctor aan de Technische Universiteit Delft, op gezag van de Rector Magnificus Prof. ir. K.C.A.M. Luyben, voorzitter van het College voor Promoties, in het openbaar te verdedigen op vrijdag 24 mei 2013 om 12.30 uur ¨ ˙ door Ay¸se Ne¸sen SURMEL I-ANAC ¸ Master of Science in Buildings Science, Master of Science in Science and Technology Policy Studies, Middle East Technical University, Turkije ˙ geboren te Izmir, Turkije.

(4) Dit proefschrift is goedgekeurd door de promotor: Prof. dr. ir. J.W.G. van de Kuilen Prof. ir. F.S.K. Bijlaard. Samenstelling promotie–commissie: Rector Magnificus, Prof. dr. ir. J.W.G. van de Kuilen, Prof. ir. F.S.K. Bijlaard, Prof. dr. Z. Kovacs, Prof. dr. ir. A. Janssens, Prof. dr. ing. U. Knaack, Prof. dr. ir. H.A.J. de Ridder, Drs. W.F. Gard,. voorzitter Technische Universiteit Delft, promotor Technische Universiteit Delft, promotor University of West Hungary Universiteit Gent Technische Universiteit Delft Technische Universiteit Delft Technische Universiteit Delft. This research has been partly funded by the European Commission 6th Framework Program (Project ECWINS, No-COLL-CT-2006-030490).. ISBN 978-94-6186-154-2 ¨ ˙ c 2013 by Ay¸se Ne¸sen SURMEL Copyright I-ANAC ¸ All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage and retrieval system, without the prior permission of the author. Printed in the Netherlands.

(5) To my mum and dad,.

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(7) Acknowledgement Over the years it has been my good fortune to meet and work with a number of people who have contributed my research directly or indirectly. I would like to express my gratitude to my promoters Prof. Jan-Willem van de Kuilen and Prof. Frans Bijlaard. I am very thankful for the academic freedom they provided me along with their support that made it possible to complete this thesis. A list that has far too many names to mention separately of collaborators and partners have contributed to the research with their questions and detailed discussions during the course of research project ECWINS. The co-operation of project members in the Netherlands Organisation for Applied Scientific Research (TNO), the test results provided by the Technical Research Centre of Finland (VTT), The Trees and Timber Institute of the National Research Council of Italy (CNR-Ivalsa) and University of West Hungary (UWH) and additionally the inspection tests carried out at the Test Centre for Building Elements (PfB-Rosenheim) is gratefully acknowledged. I am particularly indebted to Prof. Kovacs Zsolt. Our discussions with him have been great input to this research. He did not only provide his expertise with patience but also shown sincere hospitality during my stay in Sopron, Hungary. I would like to thank Prof. H.A.J. de Ridder who has created the financial support for the last nine months of my study in TU Delft. I am grateful to my committee members who have contributed to this thesis with their comments and questions. There are two colleagues whom I would specifically like to thank for their support over the years. Geert Ravenshort has provided valuable comments and guidance at the initial steps of modelling of resistance to wind load. Wolfgang Gard has always been a thorough discussion partner. I am amazed with his determination to analyse each situation from different perspectives and his limitless tolerance even in the face of the most difficult conflicts. I would like to extend my gratitude to my colleagues in Ecofys; Thomas and Jetty for providing the flexibility that helped me to finalize the thesis and my office mates Jolanda, Sikko, Ronald, Antonin and Willemijn for their support and encouragement. A number of people have been fellow researchers, friends and building blocks of creating a second home in Netherlands. With them all this journey has become a. i.

(8) ii. Acknowledgement. memorable experience. Edi, Sofia, Carmen, Giorgia and Maria have been a great support group both in TU Delft and outside work. I owe special thanks to Sofia for bearing in the office with me during the thesis writing phase and Carmen for her help from the first day of PhD to the last, her patience in reading the first draft entirely and suggesting numerous improvements. Particular thanks to Joost for sharing time to translate the propositions and summary to Dutch. Many thanks to Nazlı, Esra and Sevin¸c, for simply being there for everything whenever I needed. Along with them, it was a great pleasure to share long chats with Nihal, Narin and ˙ Melis. I owe thanks to Ilhan, Alper, Oytun, Dennis, Joao, Berk, O˘guzhan, Emine, Ne¸se, Stephen, Erdem, Merve, Duygu, Richard, Umut & Umut and new members Merle, Deniz and Arya for surrounding me with their lively atmosphere. I could not have asked for a better group of people for keeping me company. I am grateful to my friends back in Ankara. Yonca and G¨ ulbahar have always made me feel that I still have a home there, as if I have never left. I wish to thank to Cenk and Saner for actually never being involved in subjects related to my research. Particular thanks to U˘ gur Yal¸cıner for the inspiration he gave me and always believing in me. I was particularly lucky to have Melis and Emre by my side. It was great to grow up with them and even nicer to grow older with them and Tuncay. Wherever we ended up living, they have been and will be family to me. I would like to thank aunt Nuray for visiting me in the Netherlands. Together with uncle Naci, they have given me their always warm welcome and been the part of ˙ the joy of visiting Izmir. Special thanks to mother Birsen, father Yavuz, Ilker and C ¸ i˘ gdem for their support and encouragement. My family provided me the most beautiful childhood and made me the person I am today. I would like to mention my grandmother Emine, in her memory, for her commitment to us. I am thankful to my parents, S¸encan and Nedret, for their love, dedication, their unconditional support in all my choices and giving me the best companion, my sister G¨ ul¸sen, to share my life with. Without them none of this would be remotely possible. There are no words and ways to thank Caner for the things he brought to my life and his support to complete this thesis. He is my friend, colleague and best critic. He is Life to me..

(9) Summary. Windows and doors are essential elements of buildings. These seemingly simple components have become increasingly complex over the last decades. They have to fulfil an increased number of functions which ask for contradictory solutions and need to comply with more and more severe requirements. Windows and doors need to be transparent to allow vision and passage of light, they need to open for ventilation and at the same time, they have to resist external conditions such as wind loads, sound transmission, thermal transmittance, air and water infiltration. Additionally, windows and doors need to fulfil user requirements such as ease of operation and allowance for cleaning. Due to contradicting functions, windows and doors have become complex assemblies in which sub-components are brought together to fulfil various requirements. Performance of the assembly as a whole is determined by the composition of the sub-components and quality of manufacturing and installation. The level of accomplishment of requirements essentially influences the health and safety of the occupants as well as the indoor air quality. The methods for performance determination of windows and doors are regulated by the European harmonized standard “EN 14351 (2010): Windows and doors Product standard, Performance characteristics”. The first part of this standard lists twentytwo material independent performance requirements of which seventeen require full scale tests. Furthermore, windows and doors are highly customized and are not produced in large series to meet specific requirements of building design and their occupants. Thus, the performance determination procedures and consequent extensive testing require allocation of manufacturers resources. Another major problem is caused by the current methods for performance assessment by physical testing. Every test is afflicted with uncertainties due to sampling and measurement methods. Yet, little is known about the extent and effect of these test-related uncertainties on the reliability of the performance assessment. Therefore, effective and resource efficient performance assessment methods are needed by the window industry in Europe. This research proposes an approach towards the use of assessment models for per-. iii.

(10) iv. Summary. formance determination of windows and doors. The developed assessment models focus on the window performances in terms of their resistance against wind load, watertightness and air permeability because (1) these three performance characteristics are commonly classified as essential characteristics in most national regulations due to their significant influence on product durability and health and safety of users; (2) very few parametric studies have addressed their determination with methods other than testing; (3) the three performance characteristics are consecutively determined with a single test setup and therefore, the performance assessment for wind load, watertightness and air permeability is traditionally perceived as one single performance determination process. In order to develop assessment models, the relevant parameters have to be identified which govern the three above mentioned performance characteristics. For this scope, tests were carried out to assemble test data and information on the variation of test results. Within this study, sixty-one window specimens have been tested in three laboratories to provide data for development and verification of assessment models where required. The window configurations included in this study were single and multiple casement units representing tilt and turn, vertical and horizontal sliding and pivot operating mechanisms. The tests have been carried out in a controlled laboratory environment in accordance with EN 14351-1 (2010). A large variance was observed in repeated watertightness tests. This indicates a low reproducibility of the current test method. The test results of air permeability and resistance against wind load, were reproducible and produced reliable test data. Further testing schemes have been developed to investigate the reliability of the test results for each performance criterion. With the test results together with expert knowledge, it could be shown that for each performance characteristic, a particular modelling approach had to be chosen. A mechanical model was developed to assess the relative frontal deflection of frame members during wind load. Air permeability is determined with a two-stage regression approach. In the first stage, the amount of air loss is analysed by a multiple linear regression model and in the second stage, air permeability classes are defined by an ordinal logistic regression model. The failure mechanism of a window against water penetration and the probability of occurrence of such a failure are determined by a probabilistic model. This research showed that operation and casement configurations are influential aspects to consider in assessment of window and door performances. Operation and casement configuration prescribe a certain functional system with specific component sets; therefore the performance for each of those differs. This study measured large variations between performances of different window configurations. The hardware system, specifically the maximum distance between fixing points, the number of fixing points along the window perimeter and stiffness of the casement frame profiles, are other parameters that have been indicated as performance determinants in modelling. The modelling outcomes were verified with the available test results in order to evaluate the prediction quality of the assessment models. The verification of model results proved to be satisfactory for all studied performances..

(11) v. This research provides conclusions on the parameters that affect the performance of windows. Moreover the assessment models developed in this study enable virtual prototype testing. The window performance can be assessed and improved at the design and prototype stage and innovation processes can be accelerated. Additionally, the results of this study can be used for policy advice with respect to product performance declaration processes for windows and doors in the countries that adopt European harmonised standards. Declarations of performances with indication of variance of results can be given and definitions and methods provided in product and test standards can be improved..

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(13) Samenvatting. Ramen en deuren zijn essentiele elementen van gebouwen. Deze schijnbaar eenvoudige componenten zijn de afgelopen jaren steeds complexer geworden. Ze moeten steeds meer functionele eisen vervullen die soms tegenstrijdige oplossingen vragen. Tegelijkertijd moeten ze aan meer en strengere eisen voldoen. Ramen en deuren moeten transparant zijn om licht door te laten en een goed zicht te bieden. Ook moeten ze geopend kunnen worden voor ventilatie en tegelijkertijd moeten ze bescherming bieden tegen wind, geluid en de uitwisseling van warmte, lucht en water reguleren. Daarnaast moeten ramen en deuren makkelijk te bedienen en schoon te maken zijn. Vanwege deze soms tegenstrijdige eisen zijn ramen en deuren ingewikkelde constructies geworden die opgebouwd zijn uit verschillende componenten die nodig zijn om aan alle functionele eisen te voldoen. De prestatie van de gehele raam- of deurconstructie wordt bepaald door de onderdelen waaruit deze is opgebouwd en de kwaliteit van de fabricage en montage. De mate waarin de functionele eisen vervuld worden benvloedt de gezondheid en de veiligheid van de gebruikers en het bepaalt de luchtkwaliteit in het gebouw. De methodes voor het bepalen van de prestaties van ramen en deuren zijn gespecificeerd in de Europese standaard “EN 14351 (2010): Windows and doors Product standard, Performance characteristics”. Het eerste deel van deze standaard geeft een opsomming van 22 materiaal onafhankelijke prestatie-eisen waarvan er 17 uitvoerige testen vereisen. Om aan de specifieke eisen van ontwerpers en gebruikers van het gebouw te voldoen worden ramen en deuren op maat, klant specifiek en in kleine series gemaakt. Het bepalen van de prestaties van deze ramen en deuren door middel van uitvoerige testen legt een groot beslag op de middelen van een leverancier. Een ander probleem vormt de testmethode die gebruikt wordt om de prestatie vast te stellen. Elke test introduceert onzekerheden vanwege de gebruikte bemonsterings- en meetmethodes. Van de consequenties van deze onzekerheden voor de betrouwbaarheid van de bepaling van de prestaties van deuren en ramen is weinig bekend. Daarom heeft de Europese raam- en deurenindustrie effectieve en efficiente prestatiebepalingsmethoden nodig.. vii.

(14) viii. Samenvatting. Dit onderzoek doet een voorstel voor het gebruik van prestatiebepalingsmethodes voor deuren en ramen. De ontwikkelde bepalingsmethodes baseren zich op de prestaties van ramen op het vlak van windbestendigheid, waterdichtheid en luchtdoorlatendheid. Deze drie karakteristieke prestatiekenmerken zijn gekozen omdat (1) ze beschouwd worden als essentiele eigenschappen in de meeste nationale regelgeving (vanwege hun grote invloed op de levensduur van het product en de gezondheid en veiligheid van de gebruikers); (2) er zeer weinig parameterstudies bekend zijn die deze eigenschappen bepalen via een andere methode dan het uitvoeren van testen; (3) deze drie prestatiekenmerken bepaald worden in een testopstelling en daarom de bepaling van deze drie kenmerken beschouwd wordt als een enkel prestatiebepalingsproces. Om prestatiebepalingsmodellen te ontwikkelen moet vastgesteld worden welke parameters de drie hiervoor genoemde prestatiekenmerken bepalen. Hiervoor zijn testen uitgevoerd waarbij testgegevens en de variatie in deze testgegevens zijn vastgesteld. Voor dit onderzoek zijn 61 ramen onderzocht in drie verschillende laboratoria. De testresultaten zijn gebruikt voor de ontwikkeling en controle van het prestatiebepalingsmodel. De in dit onderzoek gebruikte raamconfiguraties zijn configuraties met een enkel en met meerdere onafhankelijk van elkaar te openen raamwerken met een draaiend, kiepend, glijdend (horizontaal en verticaal) en/of kantelend openingsmechanisme. De prestatieproeven zijn uitgevoerd onder gecontroleerde laboratoriumomstandigheden overeenkomstig EN 14351-1 (2010). Een grote spreiding is gevonden bij de waterdichtheidstesten. Dit wijst erop dat deze test slecht reproduceerbaar is. De resultaten van de windbestendigheids- en de luchtdoorlaatbaarheidstests zijn reproduceerbaar en leverden betrouwbare testgegevens. Verdere proefopstellingen en testprotocollen zijn ontwikkeld om de betrouwbaarheid van de proefresultaten voor elk prestatiekenmerk te kunnen toetsen. Door testresultaten te combineren met de kennis van deskundigen kon worden vastgesteld dat voor de modellering van elk van de drie prestatiekenmerken een specifieke aanpak gekozen moet worden. Een mechanisch model is gekozen voor de relatieve doorbuiging van de raamelementen onder windbelasting. De luchtdoorlatendheid wordt bepaald door een twee stappen regressiemodel. In de eerste stap wordt het verlies aan lucht geanalyseerd met behulp van een lineair regressiemodel. In de tweede stap wordt de luchtdoorlatendheidklasse vastgesteld met behulp van een ordinal logistic regressiemodel. Het bezwijkmechanisme van een raam tegen het indringen van water en de waarschijnlijkheid van het optreden van zo’n bezwijkmechanisme wordt gemodelleerd met een probabilistisch model. Het onderzoek heeft aangetoond dat het aantal onafhankelijk te openen raamwerken en het bedieningsmechanisme factoren zijn die invloed hebben op de bepaling van de prestaties van ramen en deuren. Het aantal raamwerken en het bedieningsmechanisme zijn functioneel leidend en bepalen de gebruikte componenten. Daarom verschillen de prestaties voor ieder van deze. Dit onderzoek heeft een grote spreiding vastgesteld in de prestaties van de verschillende raamconfiguraties. De fysieke aspecten, specifiek de afstand tussen de fixeerpunten op het raamwerk, het aantal fixeerpunten over de omtrek van het gehele raamwerk en de stijfheid van de raamprofielen zijn de.

(15) ix. andere parameters waarvan is vastgesteld dat ze bepalend zijn voor het modelleren van de prestaties. De uitkomsten van het model zijn vergeleken met de beschikbare testresultaten om de kwaliteit van prestatiebepalingsmodellen te evalueren. De resultaten van het model zijn bevredigend voor alle bestudeerde prestaties. Dit onderzoek trekt conclusies met betrekking tot de parameters die prestaties van ramen en deuren benvloeden. De modellen die tijdens dit onderzoek zijn ontwikkeld maken het mogelijk om prototypes ‘virtueel’ te testen. Daardoor kunnen de prestaties van ramen al tijdens de ontwerp- en prototypefase bepaald en verbeterd worden en kan het innovatieproces worden verbeterd. Ook kunnen de resultaten van dit onderzoek gebruikt worden voor beleidsadviezen met betrekking tot declaratie proces van de productprestatie in landen die de geharmoniseerde Europese norm volgen. De declaratie van de product prestatie kan worden gegeven inclusief een indicatie over de spreiding. De definities en de methodes die in de product- en teststandaarden gegeven worden kunnen worden verbeterd..

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(17) Contents List of Figures. xv. List of Tables. xvii. List of Symbols. xxi. 1 Introduction 1.1 Research scope . . . . 1.2 Problem definition . . 1.3 Objective and research 1.4 Research methods . . 1.5 Limitations . . . . . . 1.6 Outline of the thesis .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. 1 1 3 5 6 8 9. 2 Window configuration and performance requirements 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2 Window systems . . . . . . . . . . . . . . . . . . . . . . . . 2.2.1 Component properties . . . . . . . . . . . . . . . . . 2.2.2 Horizontal detailing . . . . . . . . . . . . . . . . . . 2.2.3 Vertical detailing . . . . . . . . . . . . . . . . . . . . 2.3 Functional requirements . . . . . . . . . . . . . . . . . . . . 2.3.1 Requirements as a structural element . . . . . . . . 2.3.2 Requirements related to operating joints . . . . . . . 2.3.3 Requirements as a surface element . . . . . . . . . . 2.4 Assessment of performance . . . . . . . . . . . . . . . . . . 2.4.1 Resistance to wind load . . . . . . . . . . . . . . . . 2.4.2 Air permeability . . . . . . . . . . . . . . . . . . . . 2.4.3 Water tightness . . . . . . . . . . . . . . . . . . . . . 2.5 Performance based approach . . . . . . . . . . . . . . . . . 2.5.1 Conformity assessment and standardization schemes 2.5.2 Assessment methods based on numerical simulation 2.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . .. 11 11 12 16 18 19 20 22 22 23 23 24 24 26 30 32 33 34. 3 Test and data analysis 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 37 37. . . . . . . . . . . . . questions . . . . . . . . . . . . . . . . . .. xi. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . .. . . . . . ..

(18) xii. Contents. 3.2. 3.3. 3.4. Laboratory testing of windows and doors . . . . . . . . . . 3.2.1 Overview of current testing procedures . . . . . . . . 3.2.2 Test specimens . . . . . . . . . . . . . . . . . . . . . 3.2.3 Test apparatus . . . . . . . . . . . . . . . . . . . . . 3.2.4 Test sequence for air permeability assessment . . . . 3.2.5 Test sequence for watertightness assessment . . . . . 3.2.6 Test sequence for resistance to wind load assessment 3.2.7 Round robin test . . . . . . . . . . . . . . . . . . . . Test results and discussions . . . . . . . . . . . . . . . . . . 3.3.1 Comparison of test results from laboratories . . . . . 3.3.2 Analysis of resistance to wind load tests . . . . . . . 3.3.3 Analysis of air permeability tests . . . . . . . . . . . 3.3.4 Analysis of watertightness tests . . . . . . . . . . . . Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. 4 Assessment of deformation due to wind load 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.2 Approach and assumptions . . . . . . . . . . . . . . . . . . . 4.3 Model development . . . . . . . . . . . . . . . . . . . . . . . . 4.3.1 Identification of critical load distribution . . . . . . . . 4.3.2 Calculation of deflection of casement periphery profiles 4.3.3 Calculation of deflection of partition profiles . . . . . . 4.4 Results and model validation . . . . . . . . . . . . . . . . . . 4.4.1 Window relative frontal deflection . . . . . . . . . . . 4.4.2 Deflection of partition profiles . . . . . . . . . . . . . . 4.5 Sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . . . 4.6 Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.7 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . . .. 37 37 42 43 44 44 46 48 48 48 49 53 56 63. . . . . . . . . . . . .. 67 67 67 69 69 71 72 74 74 75 77 80 81. 5 Assessment of air permeability 83 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 5.2 Approach and assumptions . . . . . . . . . . . . . . . . . . . . . . . 83 5.3 Methodology and model development . . . . . . . . . . . . . . . . . . 85 5.3.1 Model variables for air permeability performance . . . . . . . 86 5.3.2 Model variables for window design . . . . . . . . . . . . . . . 87 5.3.3 Multiple linear regression . . . . . . . . . . . . . . . . . . . . 88 5.3.4 Ordinal logistic regression . . . . . . . . . . . . . . . . . . . . 90 5.4 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 5.4.1 Relationship between window properties and air flow . . . . . 93 5.4.2 Relationship between window properties and air permeability classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 5.4.3 Multiple regression model for air flow . . . . . . . . . . . . . 97 5.4.4 Analysis of air permeability by ordinal logistic regression model101 5.5 Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 5.6 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110.

(19) Contents. xiii. 6 Assessment of watertightness 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.2 Approach and assumptions . . . . . . . . . . . . . . . . . . . . . 6.3 Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.1 Probabilistic modelling . . . . . . . . . . . . . . . . . . . . 6.3.2 Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.3.3 Sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . 6.4 Development of probabilistic network . . . . . . . . . . . . . . . . 6.4.1 Nodes and the structure of probabilistic network . . . . . 6.4.2 Quantification of causal relations of water leakage . . . . 6.4.3 Inferencing with evidence in BBNs . . . . . . . . . . . . . 6.5 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5.1 Window system for watertightness . . . . . . . . . . . . . 6.5.2 Failure Mechanism . . . . . . . . . . . . . . . . . . . . . . 6.5.3 Probabilistic network according to operation configuration 6.6 Model validation . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.6.1 Observed and predicted frequencies . . . . . . . . . . . . . 6.6.2 Model validation with case comparison . . . . . . . . . . . 6.7 Sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . . . . . 6.7.1 Model sensitivity . . . . . . . . . . . . . . . . . . . . . . . 6.7.2 Sub-system variable sensitivities . . . . . . . . . . . . . . 6.8 Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.9 Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .. 111 111 111 114 114 117 118 119 120 124 126 129 129 135 136 139 139 140 145 145 149 150 152. 7 Model implementation 7.1 Introduction . . . . . . . . . . . . . . . . . . . 7.2 Aggregation of assessment models . . . . . . . 7.3 Implementation of models as a computational 7.3.1 Concept model . . . . . . . . . . . . . 7.3.2 Software tool . . . . . . . . . . . . . . 7.4 Implications of model use . . . . . . . . . . . 7.4.1 Conformity declaration . . . . . . . . 7.4.2 Product Development . . . . . . . . . 7.5 Challenges and limitations . . . . . . . . . . . 7.6 Conclusions . . . . . . . . . . . . . . . . . . .. . . . . . . tool . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. 153 153 153 155 156 159 160 160 161 162 162. 8 Conclusions and recommendations 8.1 Conclusions . . . . . . . . . . . . . 8.1.1 Resistance to wind load . . 8.1.2 Air permeability . . . . . . 8.1.3 Watertightness . . . . . . . 8.2 Recommendations . . . . . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. 165 165 165 166 166 167. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. . . . . .. Bibliography. 169. Appendix. 179.

(20) xiv. Contents. A Resistance to wind load test results and specimen properties. 181. B Air permeability test results and specimen properties. 187. C Repeated watertightness test results and specimen properties. 191. D Conditional probability tables for inwards, outwards, sliding and pivot windows. 195.

(21) List of Figures 1.1. Outline of the thesis . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10. Components of a single unit window . . . . . . . . . . . . . . . . . . Examples for different configurations of fa¸cade elements (a) single unit window, (b) multiple unit window with parallel partitions, (c) multiple unit window with intersecting partitions. . . . . . . . . . . . 2.3 Window operation types (EN 12519 (2004)) . . . . . . . . . . . . . . 2.4 Determination of cross-section dimensions of profiles . . . . . . . . . 2.5 Schematic view of weather-strip types . . . . . . . . . . . . . . . . . 2.6 Parameters of design of top profile . . . . . . . . . . . . . . . . . . . 2.7 Parameters in design of bottom profile . . . . . . . . . . . . . . . . . 2.8 Parameters in design of vertical profile . . . . . . . . . . . . . . . . . 2.9 Three environmental systems that window assembly interacts simultaneously . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.10 Uses of performance assessment in construction sector . . . . . . . .. 13. 2.1 2.2. 3.1 3.2 3.3 3.4 3.5. 14 15 17 18 19 19 20 21 31. Typical image of the test chamber . . . . . . . . . . . . . . . . . . . Test set up and placement of measurement devices. . . . . . . . . . . Schematic example of measurement layout and fixing points . . . . . Possible vertical and horizontal partition configurations . . . . . . . Observed cumulative percentage of specimens for air permeability classes according to casement configuration. . . . . . . . . . . . . . . 3.6 Observed cumulative percentage of specimens for air permeability classes according to operation configuration. . . . . . . . . . . . . . . 3.7 Watertightness failure pressures observed during repeated test . . . . 3.8 Influence of window hardware on watertightness . . . . . . . . . . . . 3.9 Influence of drainage channel on watertightness . . . . . . . . . . . . 3.10 Observed position of water leakage . . . . . . . . . . . . . . . . . . .. 43 47 50 52. 4.1 4.2 4.3. 69 70. 4.4 4.5. Simplified calculation of moment of inertia for Specimen 9 . . . . . . Possible wind load distributions for a single unit . . . . . . . . . . . Load distributions on window configurations with horizontal (a) and vertical (b) partition members . . . . . . . . . . . . . . . . . . . . . . Relative Deflection assessment results by test and calculation methods Frontal deflection of vertical partition by casement configuration . . xv. 55 56 58 61 61 62. 70 75 76.

(22) xvi. List of Figures. 4.6 4.7 4.8 4.9. Frontal deflection of horizontal partition profiles by casement configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sensitivity of maximum relative frontal deflection . . . . . . . . . . . Maximum relative frontal deflection single unit windows . . . . . . . Maximum relative frontal deflection multi unit windows . . . . . . .. 5.1 5.2. Chapter structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Expected probabilities for AP classes according to lavg . . . . . . . . 109. 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16. Chapter structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . Steps of sensitivity analysis . . . . . . . . . . . . . . . . . . . . . . . Initial BBN structure . . . . . . . . . . . . . . . . . . . . . . . . . . A partial representation of failure network . . . . . . . . . . . . . . . Relation types developed for window failure BBN model. . . . . . . . Designation of probabilities for first event variable (EV1) . . . . . . Designation of probabilities for second event variable (EV2) . . . . . Block diagram for failure sequence . . . . . . . . . . . . . . . . . . . BBN for inwards opening windows . . . . . . . . . . . . . . . . . . . BBN for outwards opening windows . . . . . . . . . . . . . . . . . . BBN for pivot windows . . . . . . . . . . . . . . . . . . . . . . . . . BBN for sliding windows . . . . . . . . . . . . . . . . . . . . . . . . . Case by case model validation - first group . . . . . . . . . . . . . . . Case by case model validation - second group . . . . . . . . . . . . . Case by case model validation - third group . . . . . . . . . . . . . . Probability distribution of water leakage for best and worst case scenarios for inwards opening windows . . . . . . . . . . . . . . . . . . . Probability distribution of water leakage for best and worst case scenarios for outwards opening windows . . . . . . . . . . . . . . . . . . Probability distribution of water leakage for best and worst case scenarios for pivot windows . . . . . . . . . . . . . . . . . . . . . . . . . . Probability distribution of water leakage for best and worst case scenarios for vertical sliding windows . . . . . . . . . . . . . . . . . . . . Probability distribution of water leakage for best and worst case scenarios for horizontal sliding windows . . . . . . . . . . . . . . . . . . .. 6.17 6.18 6.19 6.20. 7.1 7.2 7.3 7.4 7.5 7.6. 77 78 79 79. 112 119 122 123 123 128 129 136 137 137 138 139 142 143 144 146 147 147 148 148. Aggregation of model representation . . . . . . . . . . . . . . . . . . 155 Main components of computer system for performance assessment of windows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156 Model for software architecture . . . . . . . . . . . . . . . . . . . . . 157 Class diagram for window assembly . . . . . . . . . . . . . . . . . . . 157 Sequence diagram for RWL performance . . . . . . . . . . . . . . . . 158 Example screen shot from the software interface for assessment of WT 159.

(23) List of Tables 2.1. Window design variables mentioned in previous literature related to watertightness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Comparison of test configuration for determination of watertightness performance according to EN 1027 (2000b) and ASTM 331 (1996). . 3.2 Comparison of test configuration for determination of air permeability performance according to EN 1026 (2000a) and ASTM 283 (2004) . 3.3 Comparison of test configuration for determination of resistance to wind load performance according to EN 12211 (2000d) and ASTM 330 (1998) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.4 Number of specimens in each test batch for WT according to their characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 Results of calibration tests . . . . . . . . . . . . . . . . . . . . . . . . 3.6 Average displacement at 800 Pa (mm) . . . . . . . . . . . . . . . . . 3.7 Performance classes for Resistance to Wind Load . . . . . . . . . . . 3.8 Frequency of casement configuration according to air permeability class 3.9 Frequency of operational configuration according to air permeability class . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.10 Pearsons Correlation analysis for amount of scatter and performance 3.11 Component test specimen properties . . . . . . . . . . . . . . . . . .. 30. 3.1. 5.1 5.2 5.3. Classification of predictor variables . . . . . . . . . . . . . . . . . . . Correlations among window design variables and air flow . . . . . . . Non parametric correlation between air permeability performance class and window design variables . . . . . . . . . . . . . . . . . . . . . . . 5.4 Parametric correlation between air permeability class and window design parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 Coefficients of each model for predicting air flow . . . . . . . . . . . 5.6 Case Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.7 Case-wise Diagnostics . . . . . . . . . . . . . . . . . . . . . . . . . . 5.8 Deviance differences compared with a linear function for all models . 5.9 Model Comparison . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.10 Model selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.11 Model fitting information . . . . . . . . . . . . . . . . . . . . . . . . 5.12 Model performance- observed and predicted response frequencies . . xvii. 40 41. 42 46 48 51 52 54 55 59 60 88 94 95 96 99 100 101 102 103 104 106 106.

(24) xviii. List of Tables. 5.13 Cross-tabulations of the predicted AP by the test classes. . . . . . . . . . . . 5.14 Cross-tabulations of the predicted AP test classes. . . . . . . . . . . . . . . .. classes . . . . classes . . . .. from . . . from . . .. the MRL model . . . . . . . . . . 107 the OLR by the . . . . . . . . . . 108. 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10. Probability table for EV1 provided by the expert . . . . . . . . . Expected delay of water infiltration according to given DV . . . Probability table for EV2 when EV1 occurs at 0 Pa . . . . . . . Probability table for EV2 when EV1 occurs at 250 Pa . . . . . . Conditional probability of water entering to the window assembly Design variables and possible states . . . . . . . . . . . . . . . . . Failure Mode Analysis for Watertightness . . . . . . . . . . . . . Cross tabulation of predicted WT classes and test classes . . . . Design Variable values for best and worst case scenarios . . . . . Watertightness sensitivity for window sub-systems . . . . . . . .. . . . . . . . . . .. . . . . . . . . . .. 124 125 126 126 128 131 132 140 145 150. 7.1. Cluster of model parameters . . . . . . . . . . . . . . . . . . . . . . . 154. A.1 A.2 A.3 A.4. Single unit windows deflection measurements and specimen properties Multi unit windows deflection measurements and specimen properties Displacement measurements on single casement specimens at 800 Pa Displacement measurements on multi-casement specimens at 800 Pa. 182 183 184 186. B.1 Repeated air permeability test results and specimen properties . . . 188 B.2 Descriptive Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 C.1 Repeated watertightness test results and specimen properties . . . . 192 C.2 Rule of watertightness classes . . . . . . . . . . . . . . . . . . . . . . 193 D.1 D.2 D.3 D.4 D.5 D.6 D.7. Conditional Probability of EV1 - Inwards opening tilt and turn . . . Conditional Probability of EV2 - Inwards opening tilt and turn . . . Conditional Probability of EV3 - Inwards opening tilt and turn . . . Conditional Probability of EV4 - Inwards opening tilt and turn . . . Conditional Probability of EV5 - Inwards opening tilt and turn . . . Conditional Probability of EV6 - Inwards opening tilt and turn . . . Conditional Probability of water leakage - Inwards opening tilt and turn . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D.8 Conditional Probability of EV1 - Outwards opening windows . . . . D.9 Conditional Probability of EV2 - Outwards opening windows . . . . D.10 Conditional Probability of EV3 - Outwards opening windows . . . . D.11 Conditional Probability of EV4 - Outwards opening windows . . . . D.12 Conditional Probability of EV5 - Outwards opening windows . . . . D.13 Conditional Probability of EV1 - Pivot windows . . . . . . . . . . . D.14 Conditional Probability of EV2 - Pivot windows . . . . . . . . . . . D.15 Conditional Probability of EV3 - Pivot windows . . . . . . . . . . . D.16 Conditional Probability of water leakage - Pivot windows . . . . . .. 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211.

(25) List of Tables. D.17 Conditional D.18 Conditional D.19 Conditional D.20 Conditional D.21 Conditional D.22 Conditional D.23 Conditional D.24 Conditional. xix. Probability Probability Probability Probability Probability Probability Probability Probability. of of of of of of of of. EV1- Horizontal sliding windows . . . . . EV2- Horizontal sliding windows . . . . . water leakage- Horizontal sliding windows EV1 - Vertical sliding windows . . . . . . EV2 - Vertical sliding windows . . . . . . EV3 - Vertical sliding windows . . . . . . water leakage - Vertical sliding windows . two event variables (Type III) . . . . . .. 212 213 214 215 216 217 218 219.

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(27) List of Symbols A b C D ds E G hw hp I J l lavg lmax nc nd nf ns P p pw q r s Sc St Vs wp. Area (m2 ) Width of casement (m) Corner smoothness (-) Drip (-) Existence of air cushion (-) Modulus of Elasticity of profile (N/m2 ) Deviance difference Vertical water barrier (-) Height of profile (m) Moment of inertia (m4 ) Type of joint (-) Length of operation joint (-) Opening length per fixing joints (m) Maximum distance between fixings devices (m) Number of cavities (-) Number of drainage holes (-) Number of fixing points through operational joint (-) Number of weather-strips (-) Section profile (-) Statistical significance (-) The distributed wind load on surface (N/m2 ) Linear load on frame element (N/m) Strength of correlation (-) displacement (mm) Continuity of weather-strip (-) Type of weather-strip (-) Air loss (m3 /h) Width of profile (m). xxi.

(28) xxii. List of Symbols. β µ δ δrel θ. coefficients relating the predictor variables (-) threshold (-) frontal deflection of profile (mm) relative frontal deflection of profile (-) odds of observing a particular performance class or less (-). AP APC APCO AVCP BIC BBN CASCONF CE CEN CPR DoP DV EI EV FP LL MRL OLR OPCONF OPDIR RWL RWLC SME WT WTC VIF. Air Permeability Air Permeability Class Air Permeability Overall Class Assessment and Verification of Constancy of Performance Bayesian Information Criterion Bayesian Belief Network Casement Configuration Conformité Européenne European Committee for Standardization Construction Products Regulation Declaration of Performance Design variable Bending stiffness of a profile (N m2 ) Event variable Fractional polynomial Log likelihood Multivariate linear regression Ordinal logistic regression Operation configuration Operation direction Resistance to Wind Load Resistance to Wind Load Class Small and Medium-sized Enterprises Water Tightness Water Tightness Class Variance inflation factor.

(29) Chapter 1. Introduction 1.1. Research scope. The building envelope is an artefact of the desire to regulate flow of mass (moist, air, etc.) and energy (heat and sound) between interior and exterior environments of a building. Windows and doors serve as openings in the fa¸cades, to fulfil mainly environmental, aesthetic and psychological requirements. This multi-functionality requires them to be complex systems carrying a highly componential character. Correct design and detailing of such openings may avoid the root cause of many problems affecting energy consumption, the cost of operation and maintenance as well as indoor air quality problems and health issues. Moreover, unlike many other construction products, windows and doors are mostly customised to meet specific needs of buildings and their occupants. They are normally produced according to the building design where their specifications are tailored according to each building project. Fa¸cades have specific national cultural and climatic requirements leading to different product designs. The climatic conditions have led to specific window configurations allowing triple glazing and different material preferences depending on weather, domestic industry, resources of raw material and architectural heritage. Similar to many other construction products, the performance determination of windows is traditionally carried out using laboratory tests and measurements. CE marking (Conformité Européenne) is affixed to the product that shows the conformity of the window unit with the declared performance and compliance with applicable requirements relating to European Union harmonisation legislation. The provisions of the Regulation (EU) 305/2011, Construction Products Regulation (CPR) clarifies and simplifies the legislation and reinforces the credibility of the CE marking for construction products. Performance declaration shall contain the relevant product properties by giving a specific value for a performance or assigning a performance class. Product perform1.

(30) 2. 1 Introduction. ance can be based on testing or calculation or a combination of the two. For windows and doors, the harmonized standard is EN 14351 (2010) “Windows and doors Product standard, performance characteristics”. Part 1 of the standard concerns performance determination of windows and external pedestrian door sets without resistance to fire and/or smoke leakage. Part 2 focuses on internal pedestrian doorsets without resistance to fire and/or smoke leakage characteristics. For windows and doors subject to resistance to fire and smoke leakage characteristics Part 3 of the harmonized product standard is in preparation. On one hand, the laboratory procedures provide individual assessment of manufacture and quality of the building elements. Limb (2001) suggests the controlled laboratory test as the most accurate way of determining performance such as component leakage. Klems (1983) adds that during the manufacturing, test and – if required – retrofitting of window units a detailed reference to the building, in which it will be used, is not required. Therefore, their performance is assessed in isolation as independent units. This performance assessment then allows one to judge the suitability of a window unit for use under specific climate conditions and to compare it with other windows. On the other hand, the performance declaration procedures and consequent extensive testing require allocation of manufacturers’ resources. CEN recognizes the issue and mentions in clause 27 of the CPR (2011) “It is necessary to provide for simplified procedures for the drawing up of declarations of performance in order to alleviate the financial burden of enterprises, in particular small and medium-sized enterprises (SMEs)”. This potentially jeopardizes the assurance of performance assessment of highly customized products and health and safety conditions of built environment. Thus, article 17 clause 3 of CPR mentions that “Harmonised standards shall, where appropriate and without endangering the accuracy, reliability or stability of the results, provide methods less onerous than testing for assessing the performance of the construction products in relation to their essential characteristics.” Recently, the window industry in Europe is thriving at means of effective and resource efficient conformity assessment with the help of information technologies, especially for custom built, small series window systems. Many of the existing efforts are concentrating on application of an extended shared initial type testing concept. Yet, there is no study known to the author of this research on development of models for conformity assessment of windows with a generic structure, independent of component brand. With the aim of reducing the amount of time and resources allocated for physical testing of building products, computer based models provide a support to the construction industry. Blanusa et al. (2007) discussed that once complete modelling of windows and doors becomes possible, the need for testing will be diminished. Over time, product testing for fa¸cades elements, as we know it today, may become obsolete. The only need for product testing would then be for new innovative products and/or periodic validation of the calculation programs being used. This research proposes an approach towards the use of performance assessment models with the aim of performance declaration of windows and doors. Part of this re-.

(31) 1.2 Problem definition. 3. search was conducted within the scope of the research project ECWINS, a European CE-based Assessment Tool for Flexible and Innovative Window Systems (project No. COLL-CT-2006 030490), initiated by the funding from European Commission 6th Framework Programme between 2006 and 2010. The project consortium included 30 participants; ten associations, fifteen window manufacturers who have provided the test specimens and five research institutes that were responsible for testing and data analysis. The laboratory tests were issued as initial type tests reports as a joint effort of test laboratories cooperating in the project in Technical Research Centre of Finland (VTT), The Trees and Timber Institute of the National Research Council of Italy (CNR-Ivalsa), University of West Hungary (UWH), and Netherlands Organisation for Applied Scientific Research (TNO). The project included analysis of six performance characteristics: air permeability, water tightness and resistance to wind load, thermal transmittance, acoustic performance and load bearing capacity of safety devices. Initial analysis of available test reports and model concepts were developed within the project course. This thesis focuses on the analysis and modelling that is exclusively carried out by the author on air permeability, water tightness and resistance to wind load because (1) these three performance characteristics are commonly classified as essential characteristics in most national regulations due to their significant influence on product durability and health and safety of users; (2) unlike thermal and acoustic performances very few parametric studies have addressed their determination with methods other than testing; (3) the three performance characteristics are consecutively determined with a single test setup and therefore, the performance assessment for wind load, watertightness and air permeability is traditionally perceived as one single performance determination process.. 1.2. Problem definition. Declaration of performance is recognized as a factor that will affect the manufacturers to adapt their product range to respond to future market structure. Introduction of declaration of performance for windows and doors means that every window and door type, has to be tested physically under the Assessment and Verification of Constancy of Performance, system 3, to determine the performance of a number of characteristics according to the product standard EN 14351-1 (2010). This entails initial testing of products by an accredited testing body, a nationally approved test laboratory “notified” to the European Commission. Aggravated with the increased customization to fit windows and doors into unique faade designs and user requirements, declaration of performance becomes an interface between technical and non-technical (e.g. economic, organizational, or social) considerations. To date, determination of performance by assessment methods other than testing is limited to thermal transmittance and to a lesser degree to acoustic performance. There is little study on development of performance models for air permeability, watertightness and wind load resistance of windows which are regarded as essential characteristics in national regulations. This study arose from this gap of great importance to the construction industry. It illustrates the increasing potential for the.

(32) 4. 1 Introduction. use of advanced technologies for calculation models in order to assess performance of windows and doors. The main aim in adopting a modelling approach for performance assessment is to consider individual customer requirements by enhancing product flexibility without compromising on cost and quality. Ticona and Frota (2008) describe the economic effect of certification as a double edged sword: on the one hand, it reduces product variety, but on the other, it ensures technical compatibility across countries. The current practice of performance declaration for windows will raise three main interests of local window-manufacturer with possibly contradicting effects: 1. Technical concerns • Lack of evaluation protocols: Application of harmonized standards for windows and doors are relatively new (since 2009). In the business as usual scenario, the majority of the test laboratories operate in relative isolation from their peers. A round robin test to ensure the comparability of test results from different test institutes all over Europe was not available at the time of this research. The possible differences in the interpretation of the guidelines in the standards have not been studied. The habits of testing according to previous national guides are also not considered in the current method of declaration of product performance of windows and doors. Therefore, it is likely to have different testing practices despite the test procedure is standardized on European level. • Uncertainty in test results: Performance assessment of building products by laboratory tests involves a number of different testing mechanisms depending on the scope of the performance assessment. For some of the performance characteristics, such as watertightness, the existing tests standards may not give sufficiently consistent and relevant results. Every measurement introduces some uncertainty due to the device or the measurement and the sampling method. Little is known, however, about the extent and the effect of these on the reliability of the performance declaration. The International Standardization Organization (2010) emphasizes the importance of the issue by commenting “test methods should be objective, concise and accurate, and produce unambiguous, repeatable and reproducible results, so that results of tests made under defined conditions are comparable. It is recommended that the description of test methods incorporate a statement as to their accuracy, reproducibility and repeatability.” (ISO, 2010, p. 16-17). 2. Economical concerns • Product diversity as a competitive strength: Manufacturers need to incorporate different product styles in their ranges. This is essential to cover a variety of requirements either for local needs or different climates in potential international markets. Moreover, harmonization will create a.

(33) 1.3 Objective and research questions. 5. more competitive market even though manufacturers choose to remain with their local customers. Katz and Safranski (2003) discuss that the window manufacturers will need to respond rapidly, both at home, and also in international markets, to capture and keep customers in foreign markets. • Extensive physical testing: The costs for testing increase since most of the window types are produced in small series. This, in return, affects market sustainability and product diversity if manufacturers adopt a strategy to limit their product portfolio to avoid new testing costs. Citherlet et al. (2001) present a comparison of performance simulation over testing. The authors argue that the experimental approach is time consuming and expensive, it can be argued that computer simulation is the preferred option for the holistic evaluation of design options. A numerical model is proposed in understanding and extrapolating experimental results. 3. Strategic and social concerns • Knowledge sharing: Information produced during manufacturing activities becomes a part of organizational knowledge. However, in case of window performance assessment for conformity declaration, the significant amount of information is created not only in the production workshop but also in testing laboratories. Often, this valuable information asset, in terms of performance objectives or component influences on performances, is not transferred to the knowledge of the manufacturer but, remains as the expertise of the test technician. The information is not transferred to the manufacturer, nor stored in a structured way to make it possible to be reused. This hinders the way for innovative practices. Use of modelling methods is a tool for ensuring formalized knowledge where performance influencing parameters and the resulting performances are made available to the manufacturers. • Dependency on brand names and local information: Use of extended, shared initial type testing was the response of the window industry to increased requirement of physical testing. It is based on searching for similarities between different products to assess the conformity of a new window based on existing test results. Yet, these efforts are highly fragmented throughout Europe as they are developed by different countries considering only the most common local product typologies. Moreover, they carry the risk to decrease the new and innovative product designs as they are based on only certain window configuration data and component brand information with a limited applicability.. 1.3. Objective and research questions. The main aim of this research is to develop methods for performance assessment of timber windows and doors to be evaluated appropriately without extensive physical.

(34) 6. 1 Introduction. testing. The models will be developed by integrating both data from physical testing, calculation methods and accumulated expert knowledge. Models provide information about system behaviour which can be used in new product design or prototype development and adjusting the trade off between maximizing the product performance and minimizing the testing cost to enhance product diversity and maintain tradability. In accordance with this aim, two main research questions and sub-questions are defined in this study. How reliable is the method currently applied for the declaration of performance of windows? • What are the requirements and key indicators of the three window performance characteristics, namely: resistance to wind load, air permeability and water tightness? (Chapter 2 and Chapter 3) • What are the factors that determine the reliability of performance assessment for each test procedure? (Chapter 3). • What is the availability and accuracy of performance data provided with current test procedures? (Chapter 3) How can we develop a set of computation methods for assessment of window performance to decrease physical testing? • What are the appropriate methods for developing assessment models for each performance characteristic considering the available data? (Chapter 3) • Which window characteristics have statistically significant influence on air permeability? (Chapter 5) • How can engineering methods be applied for assessment of deformation of critical window profile according to EN 12211 (2000d)? (Chapter 4) • What are the determinants of watertightness of windows systems? (Chapter 6) • How can we develop an easily accessible computer based tool for implementing performance assessment models? (Chapter 7). 1.4. Research methods. This research investigates which parameters have a major influence on the window performance in terms of its resistance against wind load, water penetration and air infiltration. A series of physical test was conducted. In total sixty–one window specimens were tested in three test institutes. Prior to the full size tests, a round robin test was conducted as a preliminary action in order to obtain coherent results..

(35) 1.4 Research methods. 7. Laboratory tests were done according to the established test methods provided by European Committee for Standardization. The test programme was coordinated by University of West Hungary. Specimens were tested in order to generate measurement data for three purposes; (1) to analyse reliability of test data and to identify shortcomings and advantages of application of harmonized tests standards; (2) to gain insight in the resistance of timber windows against wind load and penetration of water and air under standardized test procedures; (3) to generate a validation data set for the assessment models. Assessment models are proposed that would reduce the necessity of physical testing for conformity declaration of windows. To analyse the relationships between the extensive set of window design variables and the three distinct performance criteria, different methods were applied depending on the research question. The analysis of the data, selection and development of the models, as well as the sensitivity, verification and validation of results are conducted exclusively by the author for the three performance criteria. The types of methods are explained accordingly in each chapter. A brief introduction is provided here. The assessment model for resistance to wind load is based on the process of analysing test and classification standards where known engineering calculation techniques (CEN, 2005) can be adapted for performance assessment. For all the calculations, the affect of wind load is determined by representing the distribution of the wind load from the glazing panel to the surrounding frame elements. The calculation methods are applied according to the configuration of each window specimen followed by the sensitivity analysis. In order to determine the air permeability of windows analysis is based on available test results. Association between the window characteristics and the resulting air permeability performance are analysed by using partial correlation analysis. Regression analysis is used for developing the assessment model. Vulnerability of the window operating joint to water intrusion has been studied to locally estimate the failure probability of a window system using failure trees (Smith, 2001) and probabilistic networks (Mitrani, 1998). The approach presented here is: firstly to build a qualitative model of window parts and their relationships and secondly to transform the qualitative model to a graphical statistical model. The main interest of such a method lies in the propagation of the component failure states through the testing of the window. The Belief Networks theory (Neapolitan, 1990) is employed to construct probabilistic directed acyclic graph models that represent causal and statistical dependencies between window design variables, external state and system internal state variables. The qualitative aspect of the assessment model was developed through the interview process with experts who all have extensive experience in testing of windows and were therefore deemed to be classed as expert in their field for the elicitation process. Quantification of the failure probabilities were based on separate questionnaires presented to experts. Although the qualitative model structure was developed by meetings with four experts, the response to quantification of probabilities was limited to one expert from UWH. Five different failure schemes have been developed by the author for assessment of different case-.

(36) 8. 1 Introduction. ment componential complexities as well as the sensitivity analysis, verification and validation of the model with available test data. As the final stage of the research, the possible overlap between influential factors over the three performance criteria: resistance to wind load, air permeability and water tightness has been studied. A concept model was developed by the author to provide input for implementation of those as a software tool by University of West Hungary.. 1.5. Limitations. There are a number of limitations that needs to be addressed regarding the present research. One of the main limitations identified during the research was restrictions related to the number and reliability of test data. There is yet no other previous study known to the author where the laboratory tests were (i) not based on historical data but acquired at the time of the study and, (ii) acquired from multiple test laboratories simultaneously. This has provided a unique opportunity to the current research a side from a number of problems to be handled. During the study, it has been seen that the challenges regarding to the repeatability of tests among different laboratories and variability in the test results, specifically for watertightness performance, is larger than anticipated. Acknowledging the first challenge, data quality for all three performance characteristics has been ensured by distributing a detailed test procedure to all test laboratories. The procedure was applied during tests that have been carried out in parallel in three countries. After the completion of all tests, the results were investigated in terms of correct position of measurement devices, accuracy and consistency of reported results. In case of incomplete test reports or inconsistent measurement data, the cases were eliminated. The tests that were not carried out fully according to the required test standards were excluded from the analysis. The data limitations were considerably small for wind resistance and air permeability performance results, however, significant for watertightness performance results. Thus, for water tightness both issues (high variability and low repeatability) were addressed by adopting modelling methodology that was not directly based on test data. Additionally, the full size test programme was extended to analyse the variability in the results. The tests were designed specifically to include repeated tests for the determination of watertightness performance. The test data are used for verification of assessment model. However, increasing the number of repeated tests may result in higher reliability of the model predictions for water tightness performance. Another limitation concerns the requirement of considerable human effort in evaluating and stating probabilities for water leakage through window assembly. Several rounds of meetings were carried out with experts from window testing domain. The possible failure sequence on a window assembly has been drawn with four experts. However, it was only possible to get full answers from one expert for the quantification of leakage probabilities used in the model. Uncertainty is also present as.

(37) 1.6 Outline of the thesis. 9. a result of a lack of complete knowledge on the water leakage through a window assembly. In this research this uncertainty cannot be reduced due to limitations on sample and test period and the technological infeasibility (no means to observe causes of infiltration within assembly). How experts use evidence of different degrees of uncertainty in their decisions, is a major area that is yet to be discovered and is a part of larger research effort. Even with these limitations imposed by data, the results of this study provide an insight into the determination of performance of windows for three performance characteristics studied. Furthermore, the model results provide robust outputs that have good statistical reliability and validity. Performance assessment studies can benefit from these findings. Window samples included in this study were all timber frame configurations. Although it is possible that the same methods are applicable to windows made with other materials (e.g. plastic, metal), this has not been verified within this study. Including window designs with other materials may depict possible modifications in the model assumptions, increasing the applicability of performance assessment models presented here. However, further empirical evaluations are needed to replicate and extend the findings for a larger set of window designs.. 1.6. Outline of the thesis. This research includes analysis on reliability of tests, application and verification of assessment models for three window performance characteristics: resistance to wind load, air permeability and water tightness. The outline of the thesis is presented in Figure 1.1 The study begins with providing a set of definitions considering both the product and the analysis methods. The definitions determine the scope of the study and provides all the relevant background information for gaining a general overview of the product under study, the window typology and its components. In this sense, a general definition of window components which covers the definition of official standards and legislation as far as possible has been summarized. The set of parameters representing window system data and current assessment methods are presented in Chapter 2. Chapter 3 describes the full scale laboratory test programme. Results are presented for reliability analyses of windows specimens with various operation styles and different componential and configurational layouts. Repeated tests have been conducted for replicating the measurement over the same sample and examining the scatter of the resultant data. With statistical analysis, the variation of test results was determined. The levels of uncertainty inherited in the test result for different performances are studied. For each performance criterion an assessment model was developed according to data size, characteristics and available modelling methods. Chapters 4, 5 and 6 present assessment models for resistance to wind load, air permeability and water tightness.

(38) 10. 1 Introduction. Figure 1.1: Outline of the thesis. respectively. The verification and optimisation of each assessment model are also provided in the respective chapters. Chapter 7 provides an overview on the overlapping mechanisms of the three performance criteria. Integration of three models is utilized by implementing these models into a computer software tool within a single interface. Conclusions of the study are presented in Chapter 8..

(39) Chapter 2. Window configuration and performance requirements 2.1. Introduction. Resistance to differences between two environments, for instance external and internal conditions, can be achieved by adding mass or effective seals to a solid wall or a fixed fa¸cade unit. An opening in the building enclosure hinders the idea of such separation. Windows and doors are designed to admit required environmental factors from outside such as light and vision, passage of people, vehicles and ventilation. However, as a part of the complete enclosure they are required to function as a barrier for undesired environmental factors such as heat or cold, moisture and airflow. EN 12519 (2004) mentions the same multi-functionality in the terminology related to structure of a window and door. The definition of window is given in CEN (2004, section 2.2.12 ): “window, building component for closing an opening in a wall or pitched roof that will admit light and may provide ventilation”. This requirement of multi-functionality is reflected in a number of components systems in different layers of the window assembly. The appropriate systems, such as multiple glazing systems, weather-strips and structural components, are integrated into the assembly for each individual functional requirement. Aggregation of performance of each subsystem provides the total window system performance. Additionally, the interfaces and joints between those components also have a significant influence on the performance of the window. The performance assessment involves the development of models that behave similarly to the way the actual product would if it were built. The construction industry uses various methods to predict and assess performance, depending on the type of performance considered and the level of accuracy desired. Significant efforts have resulted in various assessment methodologies, certification systems and computerbased simulations. 11.

(40) 12. 2 Window configuration and performance requirements. A number of parameters and their effects on performance of windows are studied in this research. A complete list and a detailed description of variables that were analysed in this study are provided in this chapter. These descriptions are also used to avoid differences in terminology, as different components have various names in the United States, in England or in the international arena. To avoid such differences in terminology, in this study generic concepts such as vertical partition or right casement frame are used as opposed to transom and jamb. This chapter provides definitions of the components and properties of those in a window assembly with regard to their effect to resistance to wind load, air and water infiltration. The study includes analysis from system to the sub-system level. The parameters on system level relate to the complete window such as casement and operation configuration. Sub-systems involve, but they are not limited to, components of a window assembly. The connections and interfaces between those components are also regarded in this set of parameters. For instance, the type of weather-strip is considered as a component property where the position of weather-strip within the interface of casement and frame profile is also regarded as a parameter of similar significance. Although such details provided here are based the on details of a timber window, many of these principles have significance for windows made of other material. This chapter also provides an overview of assessment practices for windows and links it with the function of a window or its components.. 2.2. Window systems. An opening on the vertical fa¸cade has to fulfil the requirements of a solid wall, in terms of resistance against adverse effects of the external environment. Additionally, it has functions such as providing vision and light, being operable to enable passage and create ventilation. To satisfy multiple functions simultaneously, windows are designed and manufactured as assemblies that are composed of various components of different materials. An interface is created within the window assembly wherever materials or components are joined or change planes. The performance of such an assembly is directly related to the quality of each component as well as the detailing of their connections and interfaces. Two distinct methods of fa¸cade construction have been developed in the industry. The first type is a sealed joint system on the envelope that creates an impervious layer to water and air. The second type, a rain-screen jointed system (Garden, 1963), is based on the principle of allowing the passage of air through a restricted opening into a cavity between the building interior and exterior cladding. In terms of their application in cladding of high-rise buildings Burgess and McCardle (2000) mentioned the latter as a less vulnerable system as the components need not to function perfectly to avoid leakage of fluids. Unlike external cladding, use of a rain-screen jointed systems for windows and doors, is not directly possible due to the requirement of an operating joint. Windows and doors are equipped with.

(41) 2.2 Window systems. 13. Figure 2.1: Components of a single unit window. sealed joints where systems to avoid water and air penetration exist simultaneously. However, minor compartmentalization is provided within the assembly. Basically, a simple unit of window is a system with minimum number of components that are presented in Figure 2.1. The window frame is the basic component of a window to fix the assembly to the wall and create a stable carcass. Katsaros and Hardman (2007) mentioned that the installation method of windows has been changing during the last decade. Previously, window frames were installed on the wall, followed by attaching the casement units that are manufactured separately. The current window technology has combined the frame and casement together in a single structure. Timber, plastic, aluminium or combinations of these are the most prevailing materials used for window frames. The choice is made mainly on the basis of cost, maintenance concerns and overall appearance of the building as well as thermal, acoustic and environmental performance requirements. A window unit withholds moveable and fixed units. The non-operating parts, ‘fixed lights’ (CEN, 2004), perform better in terms of air, water prevention and thermal and acoustic insulation as they do not bear an opening joint. Casement, sash, or window wing is the moveable unit of window that provides ventilation. It is characterized by a rotational connection to the frame which can also provide sliding movement. A door casement also has the function of allowing passage and access. Active wing, leaf or sash are other common words used to describe the unit with an operating function. It consists of an infill and periphery profile members..