1、PUBLISHED DOCUMENTPD CLC/TR 50426:2004 Incorporating Corrigendum No. 1Assessment of inadvertent initiation of bridge wire electro-explosive devices by radio-frequency radiation GuideICS 13.230; 29.260.20; 33.060.20 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g5
2、4g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58PD CLC/TR 50426:2004This Published Document was published under the authority of the Standards Policy and Strategy Committee on 10 March 2005 BSI 13 December 2005ISBN 0 580 45591 2 Nati
3、onal forewordThis Published Document is the official English language version of CLC/TR 50426:2004. It is anticipated that PD CLC/TR 50426 will eventually replace BS 6657:2002 but for a transitional period both documents will be current in order for users of the standard to familiarize themselves wi
4、th the contents of the new document.The UK participation in its preparation was entrusted to Technical Committee GEL/31/-/602, Radio-frequency radiation-induced ignition and detonation, which has the responsibility to: A list of organizations represented on this committee can be obtained on request
5、to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electro
6、nic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a Published Document does not of itself confer immunity from legal obligations. aid enquirers to und
7、erstand the text; present to the responsible European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cove
8、r, an inside front cover, the CLC/TR title page, pages 2 to 101 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments15741 Corrigendum No. 113 December 2005 Revision of a national for
9、eword and corrections to figures 12(e) and 13(c)TECHNICAL REPORT CLC/TR 50426 RAPPORT TECHNIQUE TECHNISCHER BERICHT December 2004 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central S
10、ecretariat: rue de Stassart 35, B - 1050 Brussels 2004 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. CLC/TR 50426:2004 E ICS 13.230; 29.260.20; 33.060.20 English version Assessment of inadvertent initiation of bridge wire electro-e
11、xplosive devices by radio-frequency radiation Guide Evaluation de la cration par inadvertance de dispositifs lectro-explosifs par pont mtallique, par rayonnement de radiofrquence Guide Leitfaden zur Verhinderung des unbeabsichtigten Auslsens einer Zndeinrichtung mit Brckendraht durch hochfrequente S
12、trahlung This Technical Report was approved by CENELEC on 2004-08-28. CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
13、Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. CLC/TR 50426:2004 2 Foreword This Technical Report was prepared by the Technical Committee CENELEC TC 31, Electrical apparatus for explosive atmospheres - General requirements. The text of the d
14、raft was submitted to the formal vote and was approved by CENELEC as CLC/TR 50426 on 2004-08-28. _ 3 CLC/TR 50426:2004 Contents Introduction. 5 1 Scope 6 2 Normative references . 6 3 Terms and definitions 6 4 Symbols and abbreviations 8 4.1 Modulation codes 8 4.2 Polarization codes. 9 5 General cons
15、iderations 9 5.1 Radio-frequency hazard 9 5.2 Philosophy of the systematic method of approach . 10 5.3 Responsibility for making the hazard assessment 10 5.4 Recommended practices for radio silence in offshore operations. 11 6 Transmitters and transmitter output parameters 11 6.1 Types of transmitte
16、rs. 11 6.2 Frequency range . 11 6.3 Transmitter output power. 12 6.4 Antenna gain. 12 6.5 Modulation factors. 12 6.5.1 General . 12 6.5.2 Frequency modulation (FM) . 12 6.5.3 Amplitude modulation (AM) 12 6.5.4 Single sideband (SSB) operation . 13 6.5.5 Pulsed radar 13 7 Circuits for blasting and wel
17、l perforation . 13 7.1 General . 13 7.2 Typical blasting circuit layouts. 14 7.2.1 General . 14 7.2.2 Extended line blasts 14 7.2.3 Benching or 3-dimensional blasts 15 7.2.4 Multipattern blasts . 16 7.2.5 Shaft sinking 16 7.2.6 Demolition work. 17 7.3 Circuits formed during well-perforating using wi
18、reline 18 8 Electro-explosive devices 21 8.1 General . 21 8.2 Commercial EED . 21 8.3 EED hazard threshold . 23 8.4 Common mode operation 24 9 Methods of assessment for determining potential RF ignition hazards on a site where EED are used . 24 9.1 General . 24 CLC/TR 50426:2004 4 9.2 Basis of the t
19、heoretical assessments for land sites 28 9.2.1 General . 28 9.3 Initial assessment for land sites. 36 9.3.1 Initial assessment of the risk from a particular transmitter site . 36 9.3.2 Initial assessment for a particular site using EED 36 9.4 Full assessment procedure for land sites. 37 9.4.1 Proced
20、ure 37 9.4.2 Information to be obtained . 37 9.4.3 Calculation of effective field strength . 38 9.5 Safe field strength . 45 9.5.1 General . 45 9.5.2 Single EED 45 9.5.3 Single EED with extended leading wires 46 9.5.4 EED in typical quarry/demolition firing circuits . 46 9.5.5 EED in well-perforatin
21、g drilling operations . 61 9.6 Multiple transmissions . 63 9.6.1 General . 63 9.6.2 Multiple-transmission assessments for quarry/demolition sites 64 9.6.3 Multiple transmission assessments for well-perforating drilling operations . 65 9.7 Assessments for offshore drilling operations 68 10 Practical
22、on-site testing . 68 11 Safety procedures 69 11.1 General procedures. 69 11.2 Alternative means of firing. 69 12 Special applications . 69 12.1 Semi-permanent installations 69 12.2 Flammable hazard situations. 69 12.3 Use of transmitters in mines and quarries 70 12.4 Safety in transit . 70 Annex A (
23、informative) Extraction of energy from the electromagnetic field . 71 Annex B (informative) Measurement of electromagnetic fields 72 Annex C (informative) Sources of information and addresses of advisory bodies - UK ONLY . 76 Annex D (informative) Electromagnetic radiated fields and examples of radi
24、ating antennas and unintended receiving antenna characteristics 78 Annex E (informative) The effective resistance of the leading wires of an EED 86 Annex F (informative) Derivation of minimum distances of safe approach for Table 2 and Table 3 . 92 Annex G (informative) Ground-wave propagation (verti
25、cal polarization): calculation of field strength 94 Annex H (informative) Worked examples to demonstrate the effects of antenna gain 96 Annex I (informative) The effects of leading wire resistance, safety resistors and the use of EED with different characteristics 97 Annex J (informative) Derivation
26、 of Figure 12a) to Figure 12g) for EED alone incorporating the resistance of leading wires and safety resistances. 100 Bibliography 101 5 CLC/TR 50426:2004 Introduction Electromagnetic waves produced by radio-frequency (RF) transmitters (e.g. radio, television and radar) will induce electric current
27、s and voltages in any firing circuit including leading wires of the electro-explosive device (EED) on which they impinge. The magnitude of the induced current and voltages depends upon the configuration of the firing circuit and leading wires relative to the wavelength of the transmitted signal and
28、on the strength of the electromagnetic field. If the induced current which is transferred to the EED is in excess of the no fire current then the EED could initiate. This European Technical Report provides a systematic approach to assist transmitter operators, quarry managers and all others concerne
29、d with a logical method for the assessment and elimination of the initiation of EED by RF. The assessment procedures contained in this European Technical Report are based on measurements of the powers and current that can be extracted from typical firing circuits and leading wires and on the physica
30、l electrical parameters of various types of EED. CLC/TR 50426:2004 6 1 Scope This European Technical Report provides guidance on assessing the possibility of inadvertent extraction of energy from an electromagnetic field propagated from radio frequency (RF), radar or other transmitter antennas and t
31、he coupling of this energy to an electro-explosive device (EED) in a manner capable of causing initiation. The frequency range covered by this European Technical Report is 9 kHz to 60 GHz. This European Technical Report only applies to bridge-wire devices which are directly initiated by radio freque
32、ncy current and does not apply to special detonators, for example, electronic detonators. It does not cover the similar hazard arising from electromagnetic fields generated by other means, for example electric storms, electricity generating plant or power transmission lines. This European Technical
33、Report does not apply to the following equipment: air bag igniters for automotive applications (including the igniters before they are fitted); special pyrotechnic devices; pyromechanisms; igniters for fireworks; special military devices; special safety equipment. NOTE The methods of assessment from
34、 9 GHz to 60 GHz are based on extrapolation of data for frequencies below 9 GHz. 2 Normative references No normative references are made in this standard. 3 Terms and definitions For the purposes of this European Technical Report the following terms and definitions apply. 3.1 duty cycle product of p
35、ulse duration (in seconds) and the pulse repetition frequency (in pulses per second) 3.2 electro-explosive device (EED) one shot explosive or pyrotechnic device initiated by the application of electrical energy NOTE EED is used to refer to either a single electro-explosive device or several devices,
36、 to comply with general practice within the industry. 3.3 hazard potential source of danger to life, limb or health, or of discomfort to a person or persons, or of damage to property 3.4 safe distance distance outside which it is considered that there is no potential hazard 7 CLC/TR 50426:2004 3.5 n
37、o-fire energy/power/voltage/current maximum energy or steady state power/voltage/current that will not cause initiation of the most sensitive EED of any particular design NOTE The manufacturing tolerances permitted during the production of EED will cause normal statistical variation in their firing
38、characteristics. The most sensitive EED permitted by this variation sets the appropriate no-fire level, which is generally accepted as a probability no greater than 0,01 %, with a confidence level of 95 %. 3.6 round of charges (shot) one or more primed explosive charges or shots, for example main ch
39、arge, primer (if used) and detonator 3.7 toe shot shot designed to clear the foot of a face, for example a quarry face 3.8 hazard area area, of any shape, containing the transmission source or sources and within which the radiation magnitude exceeds the designated hazard threshold 3.9 hazard thresho
40、ld mean power flux density or field strength that would permit only a negligible probability of EED initiation 3.10 exploder means whereby a round of charges (shot) is fired electrically 3.11 equivalent isotropically radiated power (EIRP) product of the power supplied to the antenna and the antenna
41、gain in a given direction relative to an isotropic antenna (absolute or isotropic gain) 3.12 effective field strength value of electric field strength due to a single transmitter which is derived from the transmitter characteristics, modulation factors (see 6.5) and distance, and is used for the cal
42、culation of extractable power 3.13 antenna gain gain produced by an antenna concentrating radiation in a particular direction NOTE 1 The gain of an antenna is always related to a specified reference antenna. NOTE 2 The gain, G, of an antenna in a particular direction is given by the equation: RGA= w
43、here R is the power in Watts, W, that should be radiated from the reference antenna; A is the power in Watts, W, that should be radiated from the given antenna to give the same field strength at a fixed distance in that direction. CLC/TR 50426:2004 8 NOTE 3 The gain, which is often expressed in loga
44、rithmic form, is stated in decibels. 3.14 far field region, distant from the transmitter, in which the field strength is inversely proportional to distance in the absence of ground reflection NOTE The inner limit of the far field is generally regarded as the distance d from the transmitter defined a
45、s follows. For frequencies up to and including 30 MHz, d = 8H 2/ where H is the height of the top of the antenna above ground and is the wavelength. At frequencies above 30 MHz, d = 2W 2/ where W is the width of the antenna. 3.15 near field region close to the transmitter, which lies within the far
46、field region NOTE In the near field region the dependence of the field strength on distance is complex and mutual coupling effects can also affect the value of extractable power. 3.16 leading wire resistance total d.c. resistance of the leading wires excluding that of the EED itself 3.17 bridge wire
47、 resistance internal d.c. resistance of the EED alone 3.18 safety resistor resistor or resistors placed within the casing of an EED in order to desensitize it to the external electrical environment 4 Symbols and abbreviations 4.1 Modulation codes AM Amplitude-modulated speech or music transmission.
48、Carrier power quoted MCW Amplitude-modulated tone transmission. Carrier power quoted TV Amplitude-modulated video transmission. Peak power quoted R ( ) Pulse-modulated radar transmission. Peak power quoted. The number in brackets indicates the pulse duration in s where known FM Frequency modulation
49、FSK Frequency shift keying GFSK Gaussian frequency shift key modulation SSB Single sideband transmission. Peak envelope power quoted CW Continuous wave MSK Minimum shift keying GMSK Gaussian minimum shift keying 9 CLC/TR 50426:2004 CDMA Code division multiple access. PCM Pulse code modulation PSK Phase shift keying PM Phase modulation DQPSK Differential quadrature phase shift keying. 4.2 Polarization codes V Vertical polarization. H Horizontal polarization. V/H Either vertical or horizontal polarization, or both s
