W O O D I N C A R B O N E F F I C I E N T C O N S T R U C T I O NT o o l s , m e t h o d s a n d a p p l i c a t i o n s

E D I T O R S M a t t i K u i t t i n e n , A l i c e L u d v i g , G e r h a r d W e i s s

WOOD IN CARBON EFFICIENT CONSTRUCTIONTools, methods and applications

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IMPRINT

EDITORS

Matti Kuittinen, Alice Ludvig, Gerhard Weiss

CHAPTER COORDINATORS

Chapter 1: Matti KuittinenChapter 2: Alice LudvigChapter 3: Leif GustavssonChapter 4: Atsushi Takano Chapter 5: Tarja HäkkinenChapter 6: Annette Hafner Chapter 7: Tomi TorattiChapter 8: Matti KuittinenChapter 9: Alice Ludvig

AUTHORS

Jesper Arfvidsson, Enrico De Angelis, Ambrose Dodoo, Franz Dolezal, Leif Gustavsson, Annette Hafner, Tarja Häkkinen, Matti Kuittinen, Lauri Linkosalmi, Alice Ludvig, Oskar Mair am Tinkhof, Hildegund Mötzl, S. Olof Mundt-Petersen, Stephan Ott, Diego Peñaloza, Francesco Pittau, Roger Sathre, Christina Spitzbart, Atsushi Takano, Tomi Toratti, Tuovi Valtonen, Sirje Vares, Gerhard Weiss, Stefan Winter, Giulia Zanata

LAYOUT AND GRAPHIC DESIGN

Caroline Moinel, Atsushi Takano

FUNDING

This publication was produced with the funding of CEI-Bois.ClimateCalc CC-000025/FIHÄMEEN KIRJAPAINO OY

CLIM

ATE N

EUTRAL PRINTED MATTER

HÄMEEN KIRJAPAINO OY

441 209Printed matter

TRANSLATION

Lingsoft, Finland

PRINTING

Hämeen Kirjapaino Oy, Finland

The carbon emissions from this print job have been offset by purchasing emission reduction credits under WWF Gold Standard certification. ClimateCalc is a tool for calculating the carbon footprint of both the printing company and a specific print job. Hämeen Kirjapaino Oy is the first Finnish printing company to receive the ClimateCalc certificate.

PAPER

Cover: Ensocoat 2S 270g, Stora EnsoPaper: MultiArt Silk 130g, Stora Enso

COPYRIGHT

© 2013 CEI-Bois and the authors. All rights reserved.

ISBN: 978-9-0820-9080-2 (paper)ISBN: 978-9-0820-9081-9 (e-book)

CONTACT

CEI-BoisRue Montoyer 24, BE-1000, Brussels, Belgiumwww.cei-bois.orgEmail: info@cei-bois.orgTel. + 32 2 556 2585Fax: +32 2 287 0875

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FOREWORDS

Wood is probably the most environmentally friendly material that nature has given to man. It is made from carbon, captured from the atmosphere by trees and stored in wood, where the carbon will remain locked for the entire lifespan of the wood. It is not only a magnificent ecological material, it is also a technological material, perhaps even the most innovative and the most extraordinary one at man’s disposal.

This book entitled “Wood in Carbon Efficient Construction” provides the analytical tools and examples for calculating the carbon storage and the energy efficiency of whole buildings during their full lifecycles. It also outlines the measurements for inclusion of wooden materials in all relevant production phases as well as in the end-of-life phases. I see this book as a valuable contribution to supporting current efforts in combating climate change by enhancing the use of wood-based products as one of the main construction materials for multi-storey buildings, thereby storing vast amounts of carbon as well as saving CO2 emissions through substitution of more carbon intensive materials. Furthermore, this book can enable the reaching of European policy initiatives that aim at resource efficiency and a low carbon economy. Tackle climate change: Use more wood!

Gaston Franco

Member of the European Parliament

Chair, Forestry Subgroup of the ‘Climate Change, Biodiversity and Sustainable Development’ Intergroup of the European Parliament

There is a strong and growing societal and political push to address the environmental performance of the built environment. We appreciate this book for the information it provides on the relevance of transparent life cycle analysis for accounting the advantages of using wooden materials in construction. It gives valuable practical advice to producers, designers, architects and clients alike.

Without actively applying methods and solutions, goals like a zero emission society and the aspirations of Kyoto would remain just another unrealised environmental utopia. It is the construction industry and the public and private building developers who play a major role in all of this because more than one third of the global energy consumption and carbon emissions are attributed to the construction and operation of buildings.

It is my hope that those with the responsibility for CO2 governance at all levels will find useful information and inspiration in the pages of “Wood in Carbon Efficient Construction”.

Matti Mikkola

Chairman, CEI-Bois Board

SVP, Building Solutions, Stora Enso Building and Living

As numerous European Countries are moving towards a “zero carbon” society, the practical means to achieve such a goal are becoming increasingly vital. This initiative also touches the construction sector. Therefore the request for construction materials with no or only low CO2 emissions during the production and use phases is steadily increasing. In order to meet such demands this book not only develops common evaluation methods, but at the same time manages to show practical solutions that are based on them.

The book is one of the results of the European research project “Wood in Carbon Efficient Construction”. Leading experts and researchers from numerous European countries have been collaborating and guarantee its quality and relevance. The project has been initiated by the European initiative BWW Building With Wood under the umbrella of the European Confederation of Woodworking Industries CEI Bois. It is sponsored by the European wood industry in cooperation with national funding organisations within the WoodWisdom-Net framework.

Dr. Erich Wiesner

Chairman of the CEI Bois Building with Wood Steering Group

Chairman of the Association of the Austrian Wood Industries

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ACKNOWLEDGEMENTS

Financial support for €CO2 research work has been given by several national funding organisations:

• Austria: FFG (Österreichische Forschungsförderungsgesellschaft)

• Finland: TEKES• Germany: Projektträger Jülich• Sweden: Vinnova

Private funding has been provided by the following organisations and companies:

• Austrian Chamber of Commerce• CEI-Bois• Finnish Wood Research• Swedish Forest Industries Federation• FederLegno Arredo• GreenBuild Ltd.• Huber & Sohn GmbH & Co.KG

Editing and publishing of this book has been supported by CEI-Bois.

The editors hereby express their thanks for the above mentioned institutions. This book is a result of the collaborative work of many individuals and organisations.

We cannot thank enough all the individual authors for their efforts and their continuing work in making this book a reality. Furthermore we are grateful to all members that took part in our sometimes long and demanding steering committee meetings. In particular, we want to thank Philip Buisseret from CEI-Bois, Tuija Brandt and Matti Mikkola from Stora Enso, Pasi Typpö from GreenBuild, Jan Lagerström, Sara Färlin and Alexander Nyberg from the Swedish Forest Industries Federation, Paolo Lavisci from FederLegno Arredo, Kimmo Järvinen and Jaakko Lehto from Finnish Wood Research and Mikko Viljakainen from Puuinfo for their support. Finally we are deeply indebted to Caroline Moinel for all the intensive work she has invested into the final design and layout of the book.

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1. INTRODUCTION 9

1.1 Scope and goals of this book 101.2 The €CO2 research project 101.3 Structure of this book 10

2. BACKGROUND 13

2.1 Introduction: The relevance of carbon footprint assessment for the woodworking and construction sectors 142.2 What is life cycle assessment and carbon footprint analysis? 152.3 Environmental standards and certification schemes 16

2.3.1 Standards, norms and organisations for the building sector 162.3.2 Voluntary building certification 18

2.4 Conclusions 19

3. FUNDAMENTALS 23

3.1 Introduction 243.2 Functional units 243.3 Substitution 243.4 Allocation 243.5 Evaluation indicators 253.6 System boundary: activities 263.7 Production phase 273.8 Energy supply 283.9 Temporal system boundaries 283.10 Spatial system boundaries 283.11 Conclusions 29

4. CARBON FOOTPRINT CALCULATION METHODOLOGY 33

4.1 Introduction 344.1.1 Biogenic carbon emissions 35

4.2 Standards related to carbon footprint 364.3 Assessment procedure and assessment tools and their use 364.4 Product level 40

4.4.1 Goal and scope definition 404.4.2 System boundary for wood based products 414.4.3 Data inventory 434.4.4 Allocation of environmental impacts 434.4.5 Interpretation of results 444.4.6 Uncertainties and limitations 44

4.5 Building level 464.5.1 General issues - System boundary condition 464.5.2 Full carbon footprint analysis 474.5.3 Simple system boundary for practical implementation 52

4.6 Conclusions 55

5. ENVIRONMENTAL ASPECTS FOR RAW MATERIAL SUPPLY AND MANUFACTURING 61

5.1 Introduction 625.2 Raw material supply 625.3 Sawn timber manufacturing and carbon footprint 645.4 Optimisation and development aspects of current manufacturing processes 665.5 Conclusions 67

TABLE OF CONTENTS

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6. GOOD PRACTICES FOR CARBON EFFICIENT WOOD CONSTRUCTION 71

6.1 Goal setting and requirements 726.2 Designing a low carbon wooden house 756.3 Construction 78

6.3.1 Introduction 786.3.2 Dominance of construction phase 796.3.3 Construction process: Prefabrication 796.3.4 Construction: On-site work 806.3.5 Transportation 826.3.6 Waste management 826.3.7 Prefabrication vs. on-site construction 82

6.4 Use and maintenance 856.4.1 Introduction 856.4.2 Influence of use and maintenance phase 856.4.3 Use and operational energy need and related GHG emissions 866.4.4 Maintenance and renovations 866.4.5 Recommendations 86

6.5 Deconstruction and recycling, end-of-life 896.5.1 General 896.5.2 Legal framework 916.5.3 Building description and life cycle 926.5.4 Energy recovery 936.5.5 Material recycling 936.5.6 Reuse (with low to no modification) 946.5.7 Conclusions 94

6.6 Conclusions 95

7. SERVICE LIFE AND MOISTURE SAFETY 99

7.1 Introduction 1007.2 Some principles of building physics 1007.3 A method for including moisture safety in the building process (ByggaF) 1027.4 Important factors affecting the moisture safety in wooden buildings 1047.5 Service life considerations for timber structures 1057.6 Conclusions 106

8. CASE STUDIES 111

8.1 Introduction 1128.2 Wälluden as a case study for three new wood building systems, Sweden 114

8.2.1 Consequential approach 1168.2.2 Attributional approach 1218.2.3 Final conclusions 123

8.3 4 Holz, Mietraching, Germany 1248.4 Austrian buildings 1288.5 Joensuun Elli, Finland 1388.6 Tervakukka passive house, Finland 1428.7 Progetto C.A.S.E, L’Aquila, Italy 1468.8 Lessons learned 150

9. SUMMARY AND CONCLUSIONS 155

10. APPENDICES 159

10.1 Authors 16010.2 Abbreviations 16210.3 Picture credits 163

1. Introduction

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1 INTRODUCTION

1.1 Scope and goals of this book

The main driver for publishing this book has been to disseminate information about the scientifically proven positive effects on climate of using wood in construction. The findings are the result of a large transnational European research project. The intention has been to document findings that would be of interest to designers, construction companies, LCA professionals, researchers and decision makers.

Since the research work focused on wood construction, other material comparisons are not presented in this book, except for common reference. Because this book has been written by several authors, the text reflects different viewpoints on the same topic.

1.2 The €CO2 research project

Wood in carbon efficient construction (‘€CO2’) has been a WoodWisdom-Net research project. It started in the end of 2010 and was finished in March 2013.

The original goals of the research project were to:

1. create a holistic understanding of carbon efficiency and primary energy use in the full life-cycle of a building,

2. define the technical potential and obstacles for the use of

wood in carbon-efficient construction, 3. develop practical solutions for calculating and optimizing the

carbon footprint of different wood construction systems, and 4. disseminate the scientific results efficiently to relevant

stakeholders, including e.g. authorities, regulation developers and the construction industry.

The project consortium was formed from twenty organisations from five countries: Austria, Finland, Germany, Italy and Sweden. The main supporter of the project was CEI-Bois, and the project was coordinated by Aalto University.

1.3 Structure of this book

In the following chapter, the approaches to Life Cycle Analysis (LCA) measurements and the norms and standards for environmental assessments will be outlined (Chapter 2: “Background”).Subsequently, definitions for the functional indicators and the system boundaries will be discussed (Chapter 3: “Fundamentals”). This will be followed by an introduction of the necessary information and requirements for practical assessments at the building level (Chapter 4: “Carbon footprint calculation methodology”). Later, the life-cycle aspects for the product levels are dealt with (Chapter 5: “Environmental aspects of raw material supply and manufacturing”). Building on those findings, we will demonstrate good practices and their applications for entire buildings (Chapter 6: “Good practices for carbon efficient wood construction”) as well as the necessity of moisture safety for carbon efficiency (Chapter 7: “Service life and moisture safety”). The final chapter introduces eight case studies of wood-framed buildings with calculations of both their energy efficiency and carbon efficiency (Chapter 8: “Case Studies”). Finally, the main conclusions from the book will be summarised (Chapter 9: “Summary and conclusions”).

THE €CO2 RESEARCH CONSORTIUM

AustriaAustrian Energy Agency

BOKU University of Natural Resources and Applied Sciences

Holzforschung Austria

IBO Austrian Institute for Building and Ecology

FinlandAalto University

GreenBuild Oy

Micro-Aided Design Oy

Stora Enso

UPM

VTT Technical Research Centre

GermanyHuber & Sohn GmbH

TU München

ItalyPolitecnico di Milano

SwedenLindbäcks Bygg

Linnaeus University

Lund University

Martinsons

Moelven

SP Technical Research Institute of Sweden