Delft University of Technology Design for Sanitation How does design influence train toilet hygiene? Loth, M. DOI 10.4233/uuid:1d5f7ea6-8464-48dd-b593-f2cba9c1f493 Publication date 2021 Document Version Final published version Citation (APA) Loth, M. (2021). Design for Sanitation: How does design influence train toilet hygiene?. https://doi.org/10.4233/uuid:1d5f7ea6-8464-48dd-b593-f2cba9c1f493 Important note To cite this publication, please use the final published version (if applicable). Please check the document version above. Copyright Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons. Takedown policy Please contact us and provide details if you believe this document breaches copyrights. We will remove access to the work immediately and investigate your claim. This work is downloaded from Delft University of Technology. For technical reasons the number of authors shown on this cover page is limited to a maximum of 10. Design for Sanitation How does design influence train toilet hygiene? Marian Loth Design for Sanitation How does design influence train toilet hygiene? Dissertation for the purpose of obtaining the degree of doctor at Delft University of Technology by the authority of the Rector Magnificus prof.dr.ir. T.H.J.J. van der Hagen chair of the Board for Doctorates to be defended publicly on Friday 23 april 2021 at 12:30 o’clock by Maria LOTH Master of Science in Industrial Design Engineering, Delft University of Technology, the Netherlands born in Bunnik, the Netherlands This dissertation has been approved by the promotors. Composition of the doctoral committee: Rector Magnificus chairperson Prof.ir. D.J. van Eijk Delft University of Technology, promotor Dr.ir. J.F.M. Molenbroek Delft University of Technology, copromotor Independent members: Prof.dr. C. Greed University of West England Bristol, UK Prof.dr.ing. R. Bruder Darmstadt University of Technology, BRD Prof.dr. B. Möllring Muthesius University of Fine Arts and Design, BRD Prof.dr. S. van der Geest University of Amsterdam Prof.dr. P. Vink Delft University of Technology Prof.dr.ir. R.H.M. Goossens Delft University of Technology, reserve member This research project has partly been funded by the Ministry of Infrastructure and Water Management and the NS Dutch Railways: Keywords: train, toilet, hygiene, accessibility, urinal, observational research, Proofreading: Roger Staats Graphic design: Marieke de Roo, Delft Pictogram cover: Mijksenaar Printer: Ipskamp Printing ISBN 978-94-6421-320-1 An electronic copy of this dissertation is available at www.repository.tudelft.nl © Marian Loth 2021 All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system without permission from the author. The toilet touches our lives, but we do not want to touch the toilet Table of contents Summary 09 Samenvatting 16 1 Introduction 24 1.1 Hygiene 29 1.2 Hygienic Train Toilet (HTT) 31 1.3 Aim of the thesis 33 1.4 Research questions 34 1.5 Methods 36 1.6 Structure of the thesis 37 Part A: literature and surveys 40 2 Public sanitation: a literature survey 42 2.1 Introduction 43 2.2 Sanitation 44 2.3 Hygiene 46 2.4 Toilets 50 2.5 Toilet usage 58 2.6 Highlights from the toilet literature 60 2.7 Discussion 64 2.8 Conclusions and recommendations 65 3 Train travellers’ needs and use of train toilets: a questionnaire 66 3.1 Introduction 67 3.2 Questionnaire 68 3.3 Representativity 72 3.4 Results 76 3.5 Discussion 82 3.6 Conclusions and recommendations 85 Part A: Recap 88 Part B: experiments 90 4 Hand luggage in train toilets 92 4.1 Introduction 93 4.2 Method questionnaire 94 4.3 Method observational research 95 4.4 Results questionnaire 102 4.5 Results observational research 103 4.6 Discussion 108 4.7 Conclusions and recommendations 112 5 Observing urination in moving trains 114 5.1 Introduction 115 5.2 Method 116 5.3 Results 122 5.4 Discussion 138 5.5 Conclusions 141 5.6 Acknowledgements 142 6 Reducing urine spillage 144 EXPERIMENT 1: BACKSPLASH 6.1 Introduction backsplash experiment 1 146 6.2 Method backsplash experiment 1 148 6.3 Results backsplash experiment 1 151 6.4 Discussion backsplash experiment 1 152 6.5 Implication for design to reduce backsplash 156 6.6 Conclusion backsplash experiment 1 159 EXPERIMENT 2: DISPERSION OF URINE 6.7 Introduction dispersion experiment 2 160 6.8 Method dispersion experiment 2 162 6.9 Result dispersion experiment 2 163 6.10 Discussion dispersion experiment 2 166 6.11 Implication for design to reduce dispersion 169 6.12 Conclusion dispersion experiment 2 170 EXPERIMENT 3: DIRECTING THE URINE STREAM IN A MOVING ENVIRONMENT 6.13 A moving environment experiment 3 171 6.14 Method a moving environment experiment 3 172 6.15 Discussion a moving environment experiment 3 174 6.16 Implication for design to direct the urine stream in a moving environment 174 6.17 Conclusion a moving environment experiment 3 175 6.18 Conclusion chapter 6 reducing urine spillage 176 6.19 Acknowledgement chapter 6 reducing urine spillage 177 Part B: Recap 178 Part C: design 180 7 Mock-up 1: a separate family sit-toilet and urinal 182 7.1 Introduction 183 7.2 Design of mock-up 1 183 7.3 Method mock-up 1 testing 190 7.4 Results 194 7.5 Discussion 199 7.6 Conclusions 204 8 Mock-up 2: a combined family sit-toilet and urinal 206 8.1 Introduction 207 8.2 Design of mock-up 2 208 8.3 Method mock-up 2a testing 217 8.4 Results 221 8.5 Mock-up 2a test: discussion and conclusion 229 8.6 Testing mock-up 2b 231 8.7 Results mock-up 2b testing urinal 234 8.8 Discussion mock-up 2a & b 239 8.9 Mock-up 2a & b conclusions 243 Part C: Recap 244 9 Conclusions and recommendations 246 9.1 How design influences train toilet hygiene 247 9.2 Why are train toilets perceived as being dirty? 249 9.3 How does its usage affect train toilet hygiene? 250 9.4 What are the implications for design of a hygienic train toilet? 252 9.5 How does design influence train toilet hygiene? 254 9.6 Reflection 258 9.7 Recommendation for future research 262 References 269 Terms and acronyms 285 Acknowledgements 288 About the author 293 Appendix https://doi.org/10.5281/zenodo.4678671 A.1.1 Research approach 02 A.3.1 Questionnaire train toilet of NS and TU Delft (in Dutch) 05 A.3.2 Results (questionnaire train toilet) 19 A.5.1 Human Research Ethics 35 A.5.2 Interviews 39 A.6.1 Experiment 1: backsplash 42 A.6.2 Experiment 2: dispersion of urine stream 45 A.7.1 Toilet laboratory 57 A.7.2 Research protocol mock-up 1 (in Dutch) 60 A.7.3 Questionnaires mock-up 1 63 A.8.1 Behind the scene 90 A.8.2 Floor plans mock-up 2 development 98 A.8.3 Research protocol mock-up 2a (in Dutch) 101 A.8.4 Questionnaires mock-up 2 104 A.8.5 Results questionnaire see-through door mock-up 2a 126 A.8.6 Research protocol mock-up 2b (in Dutch) 127 A.8.7 Questionnaires mock-up 2b (in Dutch) 129 A.9.1 Reflection train toilet design 146 Summary The toilet touches our lives, but we don’t want to touch the toilet! In other words, we try to keep a distance from toilets, particularly from public toilets. It is the availability, accessibility and hygiene of these toilets that make it possible for us to move away from home. However, due to the lack of (accessible and clean) public toilets, some people decide to stay at home. Others try to avoid the few (accessible) public toilets they encounter along their way because they perceive them to be dirty. A train toilet, a moving public toilet, suffers from the same problem. Even more so, because many different people use these toilets intensively to perform all kinds of (conflicting), i.e. dirty (toilet use) and clean (handwashing), practices in an anonymous, moving, confined and gender-neutral environment. Dutch train travellers commonly complain about the poor hygiene in train toilets; 83% state that they try to avoid using them. However, a number of traveller-groups have specific and (often) urgent need for using a train toilet; these include people with restricted mobility, older adults, and families with younger children. For them, a dirty train toilet can even become a barrier to travel. A wide variety of people use train toilets ©Astrid Keizer-Huijsing Summary 9 Train toilets become soiled because they are intensively used and infrequently cleaned. However, users themselves also play a role in keeping the toilets clean. Few studies have examined primary toilet use (i.e., urination and defecation) in relation to hygiene. This is the knowledge gap on which this study focusses. It addresses how Dutch train passengers use train toilets and how their usage affects hygiene or cleanliness. Our study was essentially initiated to reduce the barrier to travelling by train, and more specifically, to inform the design of Dutch train toilets. How can design improve the usability of train toilets and related hygiene issues so that users will leave the toilet cleaner and tidier for the next use.