TR36 Rainwater Harvesting Preview

Building Engineering Services Association Guide to good practice:InstallatIon ofRaInwateRHaRvestIng Innon ResIdentIal BuIldIngs TR/36 www.thebesa.com

Building Engineering Services AssociationGuide to good practice: AcknowledgmentsInstallatIon of Members of the drafting panel who compiled thisRaInwateR guide.HaRvestIng Innon ResIdentIal Besa (formerly B&ES) wishes to record its sincere thanks toBuIldIngs the following, without whose direct input of knowledge, time and experience this publication would not have been TR/36 produced. terry nash Pritesh Patel neil ellwood lutz Johnen alan Keating – secretary Chris Parsloe – Consultant the above are either former Besa members or representatives from the Rainwater Harvesting association. Besa also wishes to acknowledge the input from BsRIa, CIBse, CIPHe, wRas, together with the members of the technical Committee for their time, input and vetting. IsBn 978-0-903783-62-0 first Issued May 2010 ©2009 Besa BESA Publications old Mansion House eamont Bridge Penrith Ca10 2BX 01768 860405 [email protected]. www.theBESA.com

Building Engineering Services AssociationGuide to good practice: ForewordInstallatIon of Rainwater is a very precious resource.RaInwateRHaRvestIng In Rainfall levels have been extremely unpredictablenon ResIdentIal in the uK due to climate change; this has resultedBuIldIngs in extremes from drought conditions to floods in many homes and commercial premises. TR/36 Harvesting rainwater can help to overcome both problems of drought and floods by providing a constant supply of water during dry conditions and collecting excess rainfall by relieving pressure on local drains that leads to flooding. Benefits to harvesting rainwater are reductions in mains water consumption, reductions in water bills and reductions in your carbon footprint. Recycling rainwater has become a serious consideration for all new building projects. the design and construction industry recognises the importance of work- ing with specialist rainwater harvesting experts to ensure that clients re- ceive a bespoke solution for each site. the guide is intended to be part of a suite of publications covering generic installation requirements for a range of renewable energy and sustainable systems. It draws on the wide range of existing Besa publications covering good practice in building engineering systems and should be read in conjunc- tion with the wider range of tR/20 installation guides available for hot and cold water services. Clients will be able to expect systems falling within the scope of this standard to comply with its requirements when installed by Besa members. this standard is not intended to override any other client’s specifications and where new products or technologies are used full supporting manufacturer’s information shall be available if required. John Hadfield former Chairman Besa technical Committee www.theBESA.com

qoPS=o~áåï~íÉê=J=URTST=êÉîáëÉÇ=NNJUJNMWqoPU=fåëí~ää~íáçå=çÑ=_áçÑìÉä==NQLULNM==NMWQT==m~ÖÉ=R Guide to Good Practice Installation of Rainwater Harvesting in Non Residential Buildings Page 1 Page 3CONTENTS Page 7 Page 7ACKNOWLEDGEMENTS Page 9FOREWORD Page 101 Introduction Page 101.1 The bene ts of rainwater harvesting Page 112 Applicable Standards and legislation Page 123 Collection and storage Page 143.1 Collected rainwater Page 153.2 Filters and pre-treatments Page 163.3 Mains top-up water Page 173.4 Storage tanks Page 173.5 Harvested rainwater distribution pumps Page 183.6 T ank over ow with back- ow prevention Page 183.7 Ultraviolet disinfection Page 193.8 Control panels Page 204 Distribution systems Page 204.1 Direct and indirect fed systems Page 224.2 High level storage tanks Page 234.3 Distribution pipework Page 234.4 System labelling5 Commissioning6 Maintenance7 Bibliography and Sources 5