Factors Affecting the Accommodation of Thermal Movement in Halter Based Aluminium Standing Seam Systems Student: David Cottrell Supervisor: Alan Keiller Department of Architecture and Civil Engineering The University of Bath September 2014 MSc Façade Engineering Word Count: 21959 1 of 271 Declaration I hereby declare that the following dissertation ‘Factors Affecting the Accommodation of Thermal Movement in Halter Based Aluminium Standing Seam Systems’ is the outcome of my own personal work and research except where mentioned and referenced within the text. A list of references has been included. David Cottrell September 2014 2 of 271 Abstract Halter based aluminium standing seam systems have been used successfully as part of the building envelope on projects the world over, however there are a growing number of instances were failure has occurred due to the restriction of thermal movement in particular where long length sheets are used. The understanding of how the system works in accommodating and controlling thermal movement and the various factors which can affect it is of importance to prevent failures occurring. Unfortunately there is little detailed information available in the public domain which this dissertation attempts to address. The amount of thermal movement to be accommodated is often underestimated especially with uncoated aluminium which can attain much higher surface temperatures than previously envisaged. The material stresses and resultant forces are shown to be very large and can cause failure to welds at penetration details and fasteners in perimeter flashings if movement is restricted. As standing seam sheets attempt to move over the heads of the halters restriction is encountered which generates an in-plane force which can result in halters and substructures to overturn if this force is not accounted for in detail design. This will lead to penetration of the seams and potential sheet detachment. The in-plane force is determined by testing and its magnitude is influenced by the degree of misalignment of the halters. This form of testing is now compulsory for BBA approval but results of the testing are very rarely published by system manufacturers. A variety of problems are looked at in detail from purely aesthetic issues where halters are visible through the seam to where the sheets are penetrated or are being abraded away. It is seen that the permanent remedial action is replacement of the sheets and in many cases the full roof. Factors causing these problems are shown to occur during manufacturing, in detail design, out of tolerance support steelwork and through poor installation on site. Often poor installation is attributed to insufficient training. The role of the manufacturer is examined to ascertain what information and assistance is provided to the stakeholders to ensure that their systems are successfully designed and installed. The dissertation concludes with a set of recommendations for a proposed MCRMA Technical Bulletin on this subject. 3 of 271 Acknowledgements I would like to thank Alan Keiller my supervisor for this dissertation together with the other MSc Façade Engineering academic staff; Dr Steve Lo, Dr Stephen Ledbetter and David Metcalfe. The journey has been a wonderful experience and one that has been thoroughly enjoyed. It has been a pleasure meeting with my fellow students both full and part time and I now know what those that have gone through the dissertation process have experienced and what is waiting for those who will be taking this path in the coming years. For the latter enjoy the experience and good luck for the future. I would like to thank my former employers Kalzip Ltd for the opportunity to take this course in particular Dr Jürgen Neuwald. For all friends and colleagues past and present at Kalzip I wish you all the best for the future. A would also like to thank all the people who have contributed information and completed questionnaires to make this all possible. In no particular order thank you to: Kevin Turton, Allan Ineson, Trevor Downs, Clive Atkinson, Lindsey Ellis. David Hicks, Keith Bradley, Bob Troughton, Barry Jackson, Mike Otlet, Paul Clayton, Nigel Bishop, Karlfriedrich Fick, Joanne Booth, Rakesh Proag, Carlton Jones, Brian Morris, David Lowe, Andrew Dunn, Nick Selves, Keith Roberts, David Roy, Steve Darlington, Andreas Schmelzer and Tom Stultiens. Hopefully I haven’t missed anyone but if I have a big thank you anyway. A moment of reflection now. A loving tribute to my sadly missed late wife Faith, who encouraged me to take up this opportunity and started this journey with me but sadly lost her long and hard fought battle with cancer between my first and second year of the course. “If I should fall behind wait for me” FD22X. A big thank you for all the support and good wishes to my children Ste, Sam and Becky, hopefully you will see a lot more of me in the near future. To friends Bob and Maralyn, that’s one “D” down, now for the other two. To Paul, from one “semi-retired student pensioner” to another, good luck with completing your dissertation. Last but by no means least, all my love and thanks to my partner Hazel who has supported me and encouraged me over the last few months. It’s at an end, now we can start to enjoy life again!!! 4 of 271 Table of Contents Page No. Declaration 2 Abstract 3 Acknowledgements 4 Table of Contents 5 Abbreviations 10 Nomenclature 12 Equations 13 List of Figures. 14 List of Tables 19 1. Introduction 21 1.1. Introduction and Aim 21 1.2. Drivers 22 1.2.1. Industry experiences 22 1.2.2. Limited information in public domain 22 1.2.3. Lack of clarity of thermal movement tests 23 1.3. Current practice 24 1.3.1. Halter based aluminium standing seam systems 24 1.3.2. Typical thermal movement problems 26 1.3.3. Typical factors affecting performance 27 1.3.4. Key deficiencies and issues to be resolved 28 1.4. Proposed solution and contribution to knowledge 29 1.5. Scope, limitations and boundaries 30 1.6. Objectives and research methodology 31 2. Literature Review 34 2.1. Introduction 34 2.2. Industry documents 36 2.2.1. MCRMA Technical paper No.3 secret fix roofing design 36 guide 2.2.2. GDA Thermal elongation in trapezoidal and corrugated 38 aluminium sheeting for sheet thicknesses from 1.0 to 1.5 mm 5 of 271 Page No. 2.2.3. Martin Heywood – SCI Publication P346 - Best practice for 38 the specification and installation of metal cladding and secondary steelwork 2.3. System manufacturers’ technical literature and third party 40 approvals 2.3.1. System manufacturers’ technical literature 40 2.3.2. Third party approvals 41 3. Halter Based Aluminium Standing Seam Systems 43 3.1. Introduction 43 3.2. Current system configurations 45 3.3. Thermal movement accommodation and control 49 3.3.1. Thermal movement accommodation 49 3.3.2. Lateral restraint to supports 50 3.3.3. Fixed points 51 3.3.4. Comparison between halter and clip based systems 53 4. Thermal Movement and Stress 55 4.1. Introduction 55 4.2. Coefficient of thermal expansion 56 4.3. Surface temperature 57 4.4. Thermal movement and stress calculation 66 5. In-plane Force 69 5.1. Introduction 69 5.2. Results of in-plane force testing 70 5.3. Designing for In-plane forces 76 5.4. In-plane force testing in approvals and certification 79 6. Current Knowledge of Thermal Movement Problems 82 6.1. Introduction 82 6.2. Consultants’ questionnaire: Section 3 – Opinions 84 6.2.1. Statement 3.1 84 6.2.2. Statement 3.2 86 6.2.3. Statement 3.3 87 6 of 271 Page No. 6.2.4. Statement 3.4 88 6.2.5. Statement 3.5 89 6.2.6. Statement 3.6 90 6.2.7. Statement 3.7 91 6.2.8. Statement 3.8 92 6.2.9. Statement 3.9 93 6.2.10. Statement 3.10 94 6.2.11. Statement 3.11 95 6.2.12. Statement 3.12 96 6.3. Consultants’ questionnaire: Section 4 – Project specific 98 information 7. Problems Associated with Thermal Movement 103 7.1. Introduction 103 7.2. Examples of typical problems 106 7.2.1. Halters visible through seams 106 7.2.2. Halters overturning and penetrating seams 107 7.2.3. Material wear/abrasion of seams 109 7.2.4. Failure of fixed points 110 7.2.5. Splitting/cracking of welds 110 8. Factors Affecting Performance 112 8.1. Introduction 112 8.2. Examples of typical factors 114 8.2.1. Manufacture 114 8.2.2. Support structure 115 8.2.3. Detail design 116 8.2.4. Installation 117 9. System Manufacturers 120 9.1. Introduction 120 9.2. Manufacturers’ questionnaire – summary 121 9.2.1. Testing, approvals and certification 121 9.2.2. Design information 121 9.2.3. Production tolerances 122 7 of 271 Page No. 9.2.4. Support and installation tolerances 123 9.2.5. Installation 123 9.3. Alternate methods to assist the accommodation of thermal 131 movement 9.3.1. Mid-slope position of fixed point 131 9.3.2. Secret gutter or step lap detail 131 9.3.3. Increased number of fasteners in base of halter 131 9.3.4. Longer halters 132 9.3.5. Halters of alternative material 132 9.3.6. Sliding halters/clips 133 9.3.7. Halters in sliding rails 134 9.3.8. Robust substructure 134 10. Conclusions and Recommendations 135 10.1. Conclusions 135 10.1.1. Objective 1: Review available literature 135 10.1.2. Objective 2: Determine how standing seam systems 135 accommodate thermal 10.1.3. Objective 3: Determine the amount of thermal movement 136 and stress to be accommodated 10.1.4. Objective 4: Define in-plane forces in standing seam 136 systems 10.1.5. Objective 5: Define the problems that need to be resolved 136 10.1.6. Objective 6: Examine the role of the manufacturer 137 10.1.7. Objective 7: Identify alternative methods to assist the 138 accommodation of thermal movement 10.1.8. Objective 8: Propose key recommendations and guidance 138 10.2. Recommendations for MCRMA Technical Bulletin 139 10.3. Recommendations for Further Research 141 References 142 8 of 271 Page No. Appendix 148 A List of Contributors 148 B Consultants’ Questionnaire 150 B.1. Respondent 1 157 B.2. Respondent 2 163 B.3. Respondent 3 169 B.4. Respondent 4 175 B.5. Respondent 5 181 B.6. Respondent 6 187 B.7. Respondent 7 192 B.8. Respondent 8 198 B.9. Respondent 9 204 B.10. Respondent 10 209 B.11. Respondent 11 214 C Manufacturers’ Questionnaire 219 C.1. Kalzip Ltd 226 C.2. SpeedDeck Ltd 231 C.3. Ash and Lacy Ltd 236 C.4. BradClad Ltd 242 C.5. Architectural Profiles Ltd 247 C.6. Euro Clad Ltd 252 C.7. BEMO UK 257 D Brief history and development of halter based standing seam 262 systems E UK market for standing seam systems 267 9 of 271 Abbreviations APL Architectural Profiles Ltd ARS Abrasion Resistant System, polyamide modified polyurethane paint system ASHRAE American Society of Heating, Refrigerating and Air-Conditioning Engineers ASTM American Society for Testing and Materials BBA British Board of Agrément BCSA British Constructional Steelwork Association BRE Building Research Establishment BS British Standard BSI British Standards Institute CIBSE Chartered Institution of Building Services Engineers CIB CIB (Conseil International du Bâtiment) – International council for research in buildings and construction CITB Construction Industry Training Board CSCS Construction Skills Certification Scheme CT Computerised tomography CUAP Common Understanding of Assessment Procedure CWCT Centre for Window and Cladding technology DIBt Deutsches Institut für Bautechnik EN European Standard EOTA European Organisation for Technical Assessment ETA European Technical Approval FMEA Failure mode and effects analysis GDA Gesamtverband der AluminiumIndustrie (Aluminium Industry Federation) HAZ Heat affected zone ISO International Organization for Standardisation LEED Leadership in Energy and Environmental Design MCRMA Metal Cladding and Roofing Manufacturers’ Association MOB Method of Building NBS National Building Specification NFRC National Federation of Roofing Contractors NPD No performance declared NSSS National Structural Steelwork Specification PIR Polyisocyanurate PSA Property Services Agency PV Photovoltaic 10 of 271