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1、 AS/NZS 1768(Int):2003 Interim Australian/New Zealand Standard Lightning protection AS/NZS 1768(Int) Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 AS/NZS 1768(Int):2003 This Interim Joint Australian/New Zealand Standard was prepared by Joint Technical Committee EL-024, Protection Against Lig
2、htning. It was approved on behalf of the Council of Standards Australia on 27 November 2003 and on behalf of the Council of Standards New Zealand on 19 November 2003. It was published on 31 December 2003. The following are represented on Committee EL-024: Australasian Corrosion Association Australas
3、ian Railway Association Australian Chamber of Commerce and Industry Australian Electrical and Electronic Manufacturers Association Australian Institute of Petroleum Bureau of Meteorology CSIRO Telecommunications and Industrial Physics Department of Defence Department of Mines and Energy (QLD) Electr
4、icity Supply Association of Australia ITU NSG5 Institution of Engineers Australia Master Builders Australia Ministry of Economic Development (New Zealand) National Electrical and Communications Association Telstra Corporation The Association of Consulting Engineers Australia The University of Queens
5、land Transpower New Zealand 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. Standard
6、s may also be withdrawn.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 th
7、e Standards Australia web site at .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 o
8、r 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 Sta
9、ndards, 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
10、draft form for comment as DR 02359. Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 AS/NZS 1768(Int):2003 Australian/New Zealand Standard Lightning protection Originated in Australia as MC11969. Originated in New Zealand as NZS/AS 1768:1991. Previous Australian edition AS 17681991. AS 17681991
11、 and NZS/AS 17681991 jointly revised and designated as AS/NZS 1768(Int):2003. 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 writt
12、en 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 5635 2 Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 AS/NZS 1768(Int):2003 2 PREFACE This Interi
13、m Standard was prepared by the Joint Standards Australia/Standards New Zealand Committee EL-024 on Protection against Lightning to supersede AS 17681991 (NZS/AS 17681991) Lightning protection. This Interim Standard is intended to provide authoritative guidance on the principles and practices of ligh
14、tning protection for a wide range of structures and systems. It is not intended for mandatory application but, if called up in a contractual situation, compliance with this Standard requires compliance with all relevant clauses of the Standard such that the level of protection will be sufficient to
15、achieve a tolerable level of risk as determined by the risk calculation. In general, it is not economically possible to provide total protection against all the possible damaging effects of lightning, but the recommendations in this Standard will reduce the probability of damage to a calculated acce
16、ptable level, and will minimize any lightning damage that does occur. Guidance is given on methods of enhancing the level of protection against lightning damage, if this is required in a particular situation. Several important changes and additions have been made to this Interim Standard following a
17、 review of submissions relating to AS 17681991 (NZS/AS 17681991) and of the International Electrotechnical Commission (IEC) Technical Committee TC 81 documents on Lightning Protection. (a) The four IEC recommended protection levels (PL I to IV). (b) The risk index approach to assessing the need for
18、lightning protection has been replaced by a quantitative risk management approach based on the IEC methodology and software is provided, in the form of an Excel spreadsheet, to calculate the risk for particular situations. (c) The thunderday maps for Australia and New Zealand have been revised. (d)
19、A comprehensive set of design rules has been added as guidance for the provision of minimum requirements for air terminals, downconductors, equipotential bonding and earth terminations. (e) The rolling sphere method has been extended to include the four protection levels and a modification has been
20、introduced to allow a larger radius sphere when considering large flat surfaces. (f) Table 4.6 Typical section dimensions of main current-carrying components has been updated to reflect current technology (This was Table 4.4 in AS 17681991 (NZS/AS 17681991). Where a new structure is to be erected, t
21、he matter of lightning protection should be considered in the planning stage, as the necessary measures can often be affected in the architectural features without detracting from the appearance of the building. In addition to the aesthetic considerations, it is usually less expensive to install a l
22、ightning protection system during construction than afterwards. The decision to provide lightning protection may be taken without carrying out a risk assessment or regardless of the outcome of any risk assessment, for example, where there is a desire that there be no avoidable risk. Any decision not
23、 to provide lightning protection should only be made after considering the advice provided in this Standard. Where doubt exists as to the need for lightning protection, further advice should be sought from a lightning protection designer or installer. Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov
24、 2006 3 AS/NZS 1768(Int):2003 Unless it has been specified that lightning protection must be provided, the first decision to make is whether the lightning protection is needed. Section 2 provides guidance to assist in this decision. Section 3 provides advice on the protection of persons from lightni
25、ng, mainly relating to the behaviour of persons when not inside substantial buildings. Once a decision is made that lightning protection is necessary, Section 4 provides details on interception lightning protection for the building or structure. This includes information on the size, material, and f
26、orm of conductors, the positioning of air terminals and downconductors, and the requirements for earth terminations. Persons and equipment within buildings can be at risk from the indirect effects of lightning and Section 5 gives recommendations on the protective measures that may need to be applied
27、. Section 6 describes methods of lightning protection of various items not covered in earlier sections, such as communications aerials, chimneys, boats, fences, and trees. A clause is included on methods for protecting domestic dwellings and assorted structures in public places, where a complete pro
28、tection system may not be justified, but some protection is considered desirable. Section 7 sets out recommendations for the protection of structures with explosive or highly flammable contents. Section 8 gives advice on precautions to be taken during installation, inspecting, testing, and maintaini
29、ng lightning protection systems. A number of appendices are included that provide additional information and advice. The appendices form an integral part of this Interim Standard unless specifically stated otherwise. i.e. appendices identified as informative only provide supportive or background inf
30、ormation and are therefore not an integral part of this Standard. This Interim Standard will have a currency of three years from its date of publication. At the conclusion of that period, it will either be superseded by another Standard, confirmed as an Interim Standard in its present form for a fur
31、ther two year period or be withdrawn. The decision will take into account experience with its application in Australia and New Zealand and any new information on lightning protection available from the international community of experts and technical committees such as IEC TC 81. It should be noted
32、that IEC TC 81 is currently restructuring its suite of lightning protection Standards, to bring all of its different Standards and Technical Reports under one numerical reference (IEC 62305). The applicability of this integrated IEC Standard will be carefully examined when revising this Interim Stan
33、dard. Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 AS/NZS 1768(Int):2003 4 CONTENTS Page SECTION 1 SCOPE AND GENERAL 1.1 SCOPE.6 1.2 APPLICATION .6 1.3 INTRODUCTION .6 1.4 REFERENCED DOCUMENTS.7 1.5 DEFINITIONS.7 SECTION 2 ASSESSMENT AND MANAGEMENT OF RISK DUE TO LIGHTNING ANALYSIS OF NEED
34、FOR PROTECTION 2.1 INTRODUCTION .12 2.2 SCOPE OF SECTION .12 2.3 CONCEPT OF RISK.12 2.4 DAMAGE DUE TO LIGHTNING 14 2.5 RISKS DUE TO LIGHTNING 17 2.6 PROCEDURE FOR RISK ASSESSMENT AND MANAGEMENT.20 2.7 RISK MANAGEMENT CALCULATION TOOL.22 SECTION 3 PRECAUTIONS FOR PERSONAL SAFETY 3.1 SCOPE OF SECTION
35、.28 3.2 NEED FOR PERSONAL PROTECTION28 3.3 PERSONAL CONDUCT.28 3.4 EFFECT ON PERSONS AND TREATMENT FOR INJURY BY LIGHTNING 30 SECTION 4 PROTECTION OF STRUCTURES 4.1 SCOPE OF SECTION .31 4.2 PROTECTION LEVEL .31 4.3 LPS DESIGN RULES31 4.4 ZONES OF PROTECTION FOR LIGHTING INTERCEPTION 33 4.5 METHODS O
36、F PROTECTION.41 4.6 MATTERS TO BE CONSIDERED WHEN PLANNING PROTECTION.43 4.7 MATERIALS.47 4.8 FORM AND SIZE OF CONDUCTORS51 4.9 JOINTS52 4.10 FASTENERS.52 4.11 AIR TERMINALS.53 4.12 DOWNCONDUCTORS 55 4.13 TEST LINKS.56 4.14 EARTH TERMINATIONS57 4.15 EARTHING ELECTRODES.60 4.16 METAL IN AND ON A STRU
37、CTURE.61 SECTION 5 PROTECTION OF PERSONS AND EQUIPMENT WITHIN BUILDINGS 5.1 SCOPE OF SECTION .66 5.2 NEED FOR PROTECTION.66 5.3 MODES OF ENTRY OF LIGHTNING IMPULSES .66 5.4 GENERAL CONSIDERATIONS FOR PROTECTION 69 5.5 PROTECTION OF PERSONS WITHIN BUILDINGS70 5.6 PROTECTION OF EQUIPMENT.73 Accessed b
38、y TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 5 AS/NZS 1768(Int):2003 Page SECTION 6 PROTECTION OF MISCELLANEOUS STRUCTURES AND PROPERTY 6.1 SCOPE OF SECTION .80 6.2 STRUCTURES WITH RADIO AND TELEVISION AERIALS .80 6.3 STRUCTURES NEAR TREES80 6.4 PROTECTION OF TREES81 6.5 CHIMNEYS, METAL GUY-WIRES OR
39、WIRE ROPES81 6.6 PROTECTION OF MINES82 6.7 PROTECTION OF BOATS.84 6.8 FENCES87 6.9 MISCELLANEOUS STRUCTURES.88 6.10 PROTECTION OF HOUSES AND SMALL BUILDINGS.89 6.11 PROTECTION OF METALLIC PIPELINES90 SECTION 7 PROTECTION OF STRUCTURES WITH EXPLOSIVE OR HIGHLY-FLAMMABLE CONTENTS 7.1 SCOPE OF SECTION
40、.91 7.2 GENERAL CONSIDERATIONS91 7.3 AREAS OF APPLICATION91 7.4 EQUIPMENT APPLICATION92 7.5 SPECIFIC OCCUPANCIES93 SECTION 8 INSTALLATION AND MAINTENANCE PRACTICE 8.1 WORK ON SITE.99 8.2 INSPECTION99 8.3 TESTING.99 8.4 RECORDS.100 8.5 MAINTENANCE 100 APPENDICES A EXAMPLES OF LIGHTNING RISK CALCULATI
41、ONS 101 B THE NATURE OF LIGHTNING AND THE PRINCIPLES OF LIGHTNING PROTECTION.123 C NOTES ON EARTHING ELECTRODES AND MEASUREMENT OF EARTH IMPEDANCE134 D THE CALCULATION OF LIGHTNING DISCHARGE VOLTAGES AND REQUISITE SEPARATION DISTANCES FOR ISOLATION OF A LIGHTNING PROTECTION SYSTEM 151 E EARTHING AND
42、 BONDING.160 F WAVESHAPES FOR ASSESSING THE SUSCEPTIBILITY OF EQUIPMENT TO TRANSIENT OVERVOLTAGES DUE TO LIGHTNING165 G REFERENCED DOCUMENTS.169 Accessed by TAFE QUEENSLAND INSTITUTES on 09 Nov 2006 AS/NZS 1768(Int):2003 6 COPYRIGHT STANDARDS AUSTRALIA/STANDARDS NEW ZEALAND Australian/New Zealand In
43、terim Standard Lightning protection 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 sets out guidelines for the protection of persons and property from hazards arising from exposure to lightning. The recommendations specifically cover the following applications: (a) The protect
44、ion of persons, both outdoors, where they may be at risk from the direct effects of a lightning strike, and indoors, where they may be at risk indirectly as a consequence of lightning currents being conducted into the building. (b) The protection of a variety of buildings or structures, including th
45、ose with explosive or highly-flammable contents, and mines. (c) The protection of sensitive electronic equipment (e.g. facsimile machines, modems, computers) from overvoltages resulting from a lightning strike to the building or its associated services. The nature of lightning and the principles of
46、lightning protection are discussed and guidance is given to assist in a determination of whether protective measures should be taken. This Standard is applicable to conventional lightning protection systems (LPSs) that comprise air terminals, downconductors, earth termination networks and surge prot
47、ective devices (SPDs). Nothing contained within this Standard neither endorses nor implies the endorsement of non-conventional LPSs that comprise special air terminals or special downconductors that claim enhanced performance or enhanced screening over conventional systems. The performance of such s
48、ystems is outside the scope of this Standard. Irrespective of claimed performance, air terminals shall be placed in accordance with Section 4 to comply with this Standard. 1.2 APPLICATION This Standard does not override any statutory requirements but may be used in conjunction with such requirements
49、. Compliance with the recommendations of this Standard will not necessarily prevent damage or personal injury due to lightning but will reduce the probability of such damage or injury occurring. 1.3 INTRODUCTION Thunderstorms are natural phenomena and there are no proven devices and methods capable of preventing lightning flashes. Direct and nearby cloud-to-ground lightning discharges can be hazardous to persons, structures, installations and many other things in or on them. Consideration should always be given to the application of lightning p
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