AS NZS 3666.1-2002 Air-handling and water systems of buildings - Microbial control - Design, installation and.pdf
AS/NZS 3666.1:2002 Australian/New Zealand Standard Air-handling and water systems of buildingsMicrobial control Part 1: Design, installation and commissioning AS/NZS 3666.1 Building Code of Australia Primary referenced Standard Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:2002 This Joint Australian/New Zealand Standard was prepared by Joint Technical Committee ME-062, Ventilation and Airconditioning. It was approved on behalf of the Council of Standards Australia on 8 March 2002 and on behalf of the Council of Standards New Zealand on 18 April 2002. It was published on 2 May 2002. The following interests are represented on Committee ME-062: Air-Conditioning and Refrigeration Equipment Manufacturers Association of Australia Australasian Fire Authorities Council Australian Building Codes Board Australian Chamber of Commerce and Industry Australian Industry Group Australian Institute of Building Surveyors Australian Institute of Refrigeration Air Conditioning and Heating Chartered Institution of Building Services Engineers Department of Contract and Management Services, W.A. FPA Australia Institute of Refrigeration Heating and Air Conditioning Engineers New Zealand Institute of Engineers Australia Plastics and Chemicals Industries Association Property Council of Australia Additional interests participating in the preparation of this Standard: Department of Human Services (Vic) Department of Human Services (Tas) Institute of Plant Engineers Australasia National Health and Medical Research Council New South Wales Health Department Queensland Health Telstra Corporation Keeping Standards up-to-date Standards are living documents which reflect progress in science, technology and systems. To maintain their currency, all Standards are periodically reviewed, and new editions are published. Between editions, amendments may be issued. Standards may also be withdrawn. It is important that readers assure themselves they are using a current Standard, which should include any amendments which may have been published since the Standard was purchased. Detailed information about joint Australian/New Zealand Standards can be found by visiting the Standards Australia web site at www.standards.com.au or Standards New Zealand web site at www.standards.co.nz and looking up the relevant Standard in the on-line catalogue. Alternatively, both organizations publish an annual printed Catalogue with full details of all current Standards. For more frequent listings or notification of revisions, amendments and withdrawals, Standards Australia and Standards New Zealand offer a number of update options. For information about these services, users should contact their respective national Standards organization. We also welcome suggestions for improvement in our Standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. Please address your comments to the Chief Executive of either Standards Australia International or Standards New Zealand at the address shown on the back cover. This Standard was issued in draft form for comment as DR 00101. Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:2002 Australian/New Zealand Standard Air-handling and water systems of buildingsMicrobial control Part 1: Design, installation and commissioning Originated as part of AS 36661989. Previous edition AS/NZS 3666.1:1995. Second edition 2002. COPYRIGHT © Standards Australia/Standards New Zealand All rights are reserved. No part of this work may be reproduced or copied in any form or by any means, electronic or mechanical, including photocopying, without the written permission of the publisher. Jointly published by Standards Australia International Ltd, GPO Box 5420, Sydney, NSW 2001 and Standards New Zealand, Private Bag 2439, Wellington 6020 ISBN 0 7337 4452 2 Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:20022 PREFACE This Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee ME-062, Ventilation and Airconditioning, to supersede AS/NZS 3666.1:1995. This Standards forms Part 1 of a series of Standards for the microbial control of air- handling and water systems, as follows: AS/NZS 3666Air-handling and water systems of buildingsMicrobial control 3666.1Part 1:Design, installation and commissioning 3666.2Part 2:Operation and maintenance 3666.3Part 3:Performance-based maintenance of cooling water systems Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:20023 CONTENTS Page FOREWORD. 4 SECTION 1SCOPE AND GENERAL 1.1SCOPE.6 1.2OBJECTIVE6 1.3APPLICATION .6 1.4REFERENCED DOCUMENTS.7 1.5DEFINITIONS.7 SECTION 2DESIGN, INSTALLATION AND COMMISSIONING OF AIR-HANDLING SYSTEMS 2.1GENERAL.11 2.2AIR INTAKES 11 2.3EXHAUST AIR OUTLETS.11 2.4AIR FILTERS12 2.5HUMIDIFIERS12 2.6EVAPORATIVE AIR COOLING EQUIPMENT12 2.7COILS13 2.8TRAYS AND SUMPS.13 2.9CONDENSATE AND EQUIPMENT DRAINAGE.13 2.10 FAN ASSEMBLIES14 2.11 DUCTWORK AND COMPONENTS14 2.12 TERMINAL UNITS14 2.13 COMMISSIONING.14 SECTION 3DESIGN, INSTALLATION AND COMMISSIONING OF HEATED WATER SYSTEMS 3.1GENERAL.15 3.2HOT WATER SYSTEMS15 3.3WARM WATER ABLUTION SYSTEMS15 3.4COMMISSIONING.16 SECTION 4DESIGN, INSTALLATION AND COMMISSIONING OF COOLING WATERSYSTEMS 4.1GENERAL.17 4.2PUMPS18 4.3LOCATION.18 4.4DRIFT CONTROL18 4.5CONTROL OF SOLIDS18 4.6SUNLIGHT .19 4.7COMMISSIONING.19 Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:20024 FOREWORD Microbes abound in the natural environment and are normally present in low concentration level throughout buildings. Building systems are not sterile and will always contain some microbes. Generally, health hazards, which can lead to infections such as legionnaires disease or Pontiac fever, or allergic reactions such as humidifier fever, are created only when these microbes multiply to high concentrations. The three main categories of microbes that can be found in building environment are viruses, fungi and bacteria. Viruses are the simplest form of microorganism (microbe) but they can only reproduce within other living cells. The sources for viral transmission are the occupants rather than the building services. On the other hand, fungi and bacteria can colonize in building services if moisture and organic nutrients are present. Fungi (e.g. mould) attach to hard surfaces and are readily able to grow in conditions of high humidity as they extract their moisture from the air. Fortunately, they are readily controlled by the normal principles of hygiene, such as keeping surfaces dry, and by regular cleaning and disinfection with a mild bleaching agent. While fungi are difficult to eliminate, they will germinate only when moisture returns. Examples of systems that are only intermittently moist, but which are able to support fungal growths, are cooling coils, condensate trays, drain lines, ducting near cooling coils, and humidifier surfaces. Bacteria also prefer wet surfaces for growth but are generally to be found where the surfaces are submerged or at the interface between wet and dry areas. Colonization and growth of Legionella bacteria (the causative agent for legionnaires disease), can take place in any water-based system if the water is warm and supplied with nutrients. Examples of such systems relevant to building services are showers and baths, and cooling towers (and the like) used for heat rejection for which control measures are described in this Standard. Other sources include spa pools, decorative fountains, nebulizers (for hospital patients) ultrasonic humidifiers (misters at supermarket vegetable cabinets), cutting fluid (in industrial machine shops), dental equipment and, more recently, the potting mixtures and other composted material used by home gardeners. As Legionella bacteria are widespread in natural water sources, such as rivers, lakes, mud and soil, it is not surprising that they are often present in building water systems. Absolute exclusion of these particular bacteria from water systems, although a worthy objective, may not be possible nor necessary, and finding the bacteria does not by itself indicate that a source presents a risk. AS/NZS 3666.3 provides requirements for system decontamination should elevated Legionella counts be found. One type of application of particular concern is the provision of warm water for bathing or showering at some hospitals and institutions for the elderly, children and the mentally ill. This water is usually supplied at a temperature of 45°C maximum, to prevent scalding. Therefore, Legionella control by elevated temperature at the point of use is not possible. Often, a storage-type warm water system is provided rather than a hot-cold mixing system. Cases of legionnaires disease amongst susceptible people have been associated with the aerosol sprayed from showerheads or bath taps supplied by such systems. Adverse conditions can be created by the build-up of sludge in storage vessels and possible dead legs in the piping system. Regular cleaning, maintenance and disinfection of the system are required. Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:20025 The problem can be largely overcome by the provision of anti-scald, thermal shut-off devices that mix hot and cold water supplied to the shower outlets instead of using warm water storage tanks or calorifiers. Such outlets can be readily dismantled and disinfected periodically with chlorine. Alternatively, cold water, which is directly heated to produce warm water, can be used. In the case of cooling water systems that make use of cooling towers to evaporatively cool recirculating water, the risk of disease can be minimized by the following: (a)Careful attention to system design and construction features. (b)Use of drift eliminators. (c)Siting of towers away from building air intakes, populated areas and discharges from kitchen exhaust systems. (d)Maintaining the system in a clean and sound condition. (e)Controlling water quality from when water is introduced into the system. (f)Monitoring towers and water condition. Similarly, the control of all microbes able to colonize water and air-handling systems of buildings can be effected by the avoidance of growth needs, by ensuring the systems are clean, properly designed, commissioned, operated and well maintained, and by the use of appropriate water treatment techniques. Further explanatory information regarding this subject can be found in the Standards Australia/Standards New Zealand Handbook HB 32, Control of microbial growth in air- handling and water systems of buildings, and in the monograph produced by the National Environmental Health Forum entitled, Guidance for the control of Legionella found at the website www.health.sa.gov.au/pehs (click Publications then Legionella). The Australian Institute of Refrigeration Air Conditioning and Heating has produced a series of application manuals on cooling towers, water treatment, piping systems and maintenance. Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:2002 COPYRIGHT 6 STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand Standard Air-handling and water systems of buildingsMicrobial control Part 1: Design, installation and commissioning S E C T I O N 1 S C O P E A N D G E N E R A L 1.1 SCOPE This Standard specifies minimum requirements for the design, installation and commissioning of air-handling and water systems of buildings for the purposes of microbial control. It does not include requirements for refrigerated room airconditioners and non- ducted split systems. NOTE: Refer to regulatory authority for the application of the criteria to buildings. Requirements specified in this Standard are not intended for the control of the wide range of discomfort symptoms that may afflict the occupants of some buildings. NOTES: 1 The Standard covers the most common known sources of the diseases associated with air-handling and water systems of buildings. Other sources, both known and potential, include cooling water systems for refrigeration equipment and air compressors, industrial heat exchangers when opened for cleaning, decorative fountains, spray irrigation systems, and industrial water-based cutting fluid systems. 2 In the event of an outbreak of legionnaires disease, special action is necessary, which will be advised by the health authorities. 3 Further information on the control of microbial growth in air-handling and water systems of buildings is given in HB 32. 4 HB 61 provides details of the standard specifications in the NATSPEC series. 5 Operation and maintenance requirements are given in AS/NZS 3666.2. 1.2 OBJECTIVE The objective of this Standard is to assist in the control of microorganisms in building systems, particularly those associated with legionnaires disease, Pontiac fever, hypersensitivity pneumonitis and humidifier fever. 1.3 APPLICATION This Standard is intended for use by regulatory authorities, building services designers, architects, equipment manufacturers and suppliers, installers, maintenance personnel, managers, owners, and operating staff responsible for designing, installing, commissioning, operating, and maintaining the air-handling and water systems of a building. It gives minimum requirements and shall be read in conjunction with any additional recommendations given by suppliers of the equipment and with the requirements of any relevant specification or applicable regulation. NOTE: This Standard has been developed for commercial building services systems. The technical content may be applied by the regulatory authority to other commercial or industrial systems and to domestic systems incorporating a cooling water system. Licensed to Marley Temcel Australia on 11 Sep 2003. 1 user personal user licence only. Storage, distribution or use on network prohibited. AS/NZS 3666.1:2002 COPYRIGHT 7 1.4 REFERENCED DOCUMENTS The following documents are referred to in this Standard: AS 1324Air filters for use in general ventilation and airconditioning 1324.2Part 2:Methods of test 1470Health and safety at workPrinciples and practices 1657Fixed platforms, walkways, stairways and laddersDesign, construction and installation 1668The use of mechanical ventilation and air-conditioning in buildings 1668.2Part 2:Mechanical ventilation for acceptable indoor-a
