1、BRITISH STANDARD BS 6657:2002 Incorporating Corrigendum No. 1 Assessment of inadvertent initiation of bridge wire electro-explosive devices by radio-frequency radiation Guide ICS 13.280BS 6657:2002 This British Standard, having been prepared under the direction of the Electrotechnical Sector Policy
2、and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 30 October 2002 BSI 30 June 2003 First published February 1986 First revision November 1991 Second revision October 2002 The following BSI references relate to the work on this British Standar
3、d: Committee reference GEL/602 ISBN 0 580 40351 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee GEL/602, upon which the following bodies were represented: BBC British Broadcasting Corporation BEAMA Ltd. GAMBICA Chamber
4、of Shipping Engineering Equipment and Materials Users Association ERA Technology Ltd HSE Health and Safety Executive Institute of Petroleum Institution of Gas Engineers Ministry of Defence UK Defence Standardization Radio Society of Great Britain SIRA Limited UK Offshore Operators Association Limite
5、d Co-opted member Amendments issued since publication Date Amd No. Comments 14499 Corrigendum No. 1 30 June 2003 Changes to Figure 15BS 6657:2002 BSI 30 June 2003 i Contents Page Committees responsible Inside front cover Foreword iii Introduction 1 1S c o p e 1 2 Normative references 1 3T e r m s a
6、n d d e f i n i t i o n s 1 4 Symbols and abbreviations 3 5 General considerations 4 6 Transmitters and transmitter output parameters 5 7 Circuits for blasting and well perforation 7 8 Electro-explosive devices 13 9 Methods of assessment for determining potential RF ignition hazards on a site where
7、EED are used 15 10 Practical on-site testing 61 11 Safety procedures 62 12 Special applications 62 Annex A (informative) Extraction of energy from the electromagnetic field 64 Annex B (informative) Measurement of electromagnetic fields 64 Annex C (informative) Sources of information and addresses of
8、 advisory bodies 67 Annex D (informative) Electromagnetic radiated fields and examples of radiating antennas and unintended receiving antenna characteristics 69 Annex E (informative) The effective resistance of the leading wires of an EED 76 Annex F (informative) Derivation of minimum distances of s
9、afe approach for Table 2 and Table 3 80 Annex G (informative) Ground-wave propagation (vertical polarization): calculation of field strength 81 Annex H (informative) Worked examples to demonstrate the effects of antenna gain 83 Annex I (informative) The effects of leading wire resistance, safety res
10、istors and the use of EED with different characteristics 83 Annex J (informative) Derivation of Figure 12a) to Figure 12g) for EED alone incorporating the resistance of leading wires and safety resistances 85 Bibliography 87 Figure 1 Typical single extended line blasting circuits (plan view) 8 Figur
11、e 2 Typical multiple extended line blasting circuits (plan view) 8 Figure 3 Quarry blast including toe shots 9 Figure 4 Multilevel series-in-parallel demolition blast 10 Figure 5 Layout of wireline cable for offshore and land based operations 11 Figure 6 Section through a typical commercial instanta
12、neous EED 13 Figure 7 Flow diagram for hazard assessment for sites situated on land 16 Figure 8 Flow diagram for hazard assessment on offshore drilling platforms 17 Figure 9 Field strength versus distance from the transmitter (land path) 33 Figure 10 Field strength versus distance from the transmitt
13、er (sea path) 34 Figure 11 Commercial EED showing winding and overwrapping of leading wires 35 Figure 12a) Safe field strengths for Type I EED (includes the leading wire resistances) 37BS 6657:2002 ii BSI 30 June 2003 Page Figure 12b) Safe field strengths for Type II EED (includes the leading wire r
14、esistances) 38 Figure 12c) Safe field strengths for Type III EED (includes the leading wire resistances) 39 Figure 12d) Safe field strengths for Type IV EED (includes the leading wire resistances) 40 Figure 12e) Safe field strengths for Type V EED (includes the leading wire resistances) 41 Figure 12
15、f) Safe field strengths for Type VI EED (includes the leading wire resistances) 42 Figure 12g) Safe field strengths for Type VII EED (includes the leading wire and safety resistances with a minimum value of 10 7)4 3 Figure 13a) Safe field strengths for single Type I EED with extended leading wires w
16、ithin 1 m of the ground 44 Figure 13b) Safe field strengths for single Type II EED with extended leading wires within 1 m of the ground 45 Figure 13c) Safe field strengths for single Type III and IV EED with extended leading wires within 1 m of the ground 46 Figure 13d) Safe field strengths for sing
17、le Type V EED with extended leading wires within 1 m of the ground 47 Figure 13e) Safe field strengths for single Type VI EED with extended leading wires within 1 m of the ground 48 Figure 14a) Safe field strengths for Type I EED in typical loop circuits for various perimeter lengths within 1 m of t
18、he ground 49 Figure 14b) Safe field strengths for Type II EED in typical loop circuits for various perimeter lengths within 1 m of the ground 50 Figure 14c) Safe field strengths for Type III and IV EED in typical loop circuits for various perimeter lengths within 1 m of the ground 51 Figure 14d) Saf
19、e field strengths for Type V EED in typical loop circuits for various perimeter lengths within 1 m of the ground 52 Figure 14e) Safe field strengths for Type VI EED in typical loop circuits for various perimeter lengths within 1 m of the ground 53 Figure 15 Tuning conditions for loop with firing cab
20、le 54 Figure 16 Safe field strengths for a Type VII EED during stages 3 and 5 of well-perforating wireline operations 56 Figure 17 Detuning factor k for tuned loop situations 59 Figure 18 Detuning factors, k, for stage 2 60 Figure 19 Detuning factors, k, for stages 3 and 5 61 Figure D.1 Typical ante
21、nna installations (physical characteristics of transmitting antennas) 71 Figure D.2 Definition of angles 74 Figure E.1 An EED with partly opened leading wires 76 Figure E.2 An EED with an additional 180 section of line 78 Figure I.1 Safe field strengths for Type II EED 84 Table 1 Typical d.c. data o
22、n EED 14 Table 2 Minimum safe distances for commercial EEDs 19 Table 3 Minimum distances of safe approach for typical commercial EED 26 Table 4 Modulation factors 29 Table C.1 Addresses of some advisory bodies 68 Table D.1 Antennas for vertical polarization for frequencies up to and including 30 MHz
23、 69 Table D.2 Antennas for horizontal polarization for frequencies up to and including 30 MHz 70 Table D.3 Antennas for frequencies above 30 MHz 70 Table E.1 Ratio of the effective to actual resistance of leading wires 79BS 6657:2002 BSI 30 June 2003 iii Foreword This British Standard has been prepa
24、red by Technical Committee GEL/602. It supersedes BS 6657:1991, which is withdrawn. This revision is based on BS 6657:1991, the main differences being modifications to Table 2, previously Table 1, which is modified to include new transmitters and to include additional types of EED including those us
25、ed in well perforation, and the inclusion of a new Table 1 detailing the parameters of typical EED used in this document. NOTE The decimal comma is used throughout this standard in place of the decimal point. This publication does not purport to include all the necessary provisions of a contract. Us
26、ers are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 to 87 and a back cover. The BSI copyright notice displa
27、yed in this document indicates when the document was last issued.iv blankBS 6657:2002 BSI 30 June 2003 1 Introduction Electromagnetic waves produced by radio-frequency (RF) transmitters (e.g. radio, television and radar) will induce electric currents and voltages in any firing circuit including lead
28、ing 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 on the strength of the electromagnetic field. If th
29、e induced current which is transferred to the EED is in excess of the no fire current then the EED could initiate. This British Standard provides a systematic approach to assist transmitter operators, quarry managers and all others concerned with a logical method for the assessment and elimination o
30、f the initiation of EED by RF. The assessment procedures contained in this British Standard are based on measurements of the powers and current that can be extracted from typical firing circuits and leading wires and on the physical electrical parameters of various types of EED. 1 Scope This British
31、 Standard 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 the coupling of this energy to an electro-explosive device (EED) in a manner capable of causing ini
32、tiation. The frequency range covered by this British Standard is 9 kHz to 60 GHz. This British Standard only applies to bridge-wire devices which are directly initiated by radio frequency current and does not apply to special detonators, for example, electronic detonators. It does not cover the simi
33、lar hazard arising from electromagnetic fields generated by other means, for example electric storms, electricity generating plant or power transmission lines. This British Standard does not apply to the following equipment: air bag igniters for automotive applications (including the igniters before
34、 they are fitted); special pyrotechnic devices; pyromechanisms; igniters for fireworks; special military devices; special safety equipment. NOTE The methods of assessment from 9 GHz to 60 GHz are based on extrapolation of data for frequencies below 9 GHz. 2 Normative references No normative referenc
35、es are made in this standard. 3 Terms and definitions For the purposes of this British Standard the following terms and definitions apply. 3.1 duty cycle product of pulse duration (in seconds) and the pulse repetition frequency (in pulses per second) 3.2 electro-explosive device (EED) one shot explo
36、sive 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, to comply with general practice within the industry. 3.3 hazard potential source of danger to life, limb or health, or of discomfort
37、to a person or persons, or of damage to propertyBS 6657:2002 2 BSI 30 June 2003 3.4 safe distance distance outside which it is considered that there is no potential hazard 3.5 no-fire energy/power/voltage/current maximum energy or steady state power/voltage/current that will not cause initiation of
38、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 characteristics. The most sensitive EED permitted by this variation sets the appropriate no-fire level, which is generally
39、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 charge, 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
40、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 threshold mean power flux density or field strength that would permit only a negligible probability of EED initiation 3.10 explode
41、r 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 gain in a given direction relative to an isotropic antenna (absolute or isotropic gain) 3.12 effective field strength value
42、 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 calculation of extractable power 3.13 antenna gain gain produced by an antenna concentrating radiation in a particular directi
43、on 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: G = where R is the power in Watts, W, that should be radiated from the reference antenna; A is the power in Watts, W, that should
44、 be radiated from the given antenna to give the same field strength at a fixed distance in that direction. NOTE 3 The gain, which is often expressed in logarithmic form, is stated in decibels. R A -BS 6657:2002 BSI 30 June 2003 3 3.14 far field region, distant from the transmitter, in which the fiel
45、d 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 as follows. For frequencies up to and including 30 MHz, d = 8H 2 / where H is the height of the top of the a
46、ntenna 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 field region NOTE In the near field region the dependence of the field strength on distance is complex an
47、d 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 resistance internal d.c. resistance of the EED alone 3.18 safety resistor resistor or resistors placed w
48、ithin the casing of an EED in order to desensitize it to the external electrical environment 4 Symbols and abbreviations 4.1 Modulation codes 4.2 Polarization codes AM Amplitude-modulated speech or music transmission. Carrier power quoted. MCW Amplitude-modulated tone transmission. Carrier power quo
49、ted. 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 4s where known. FM Frequency modulation. 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. CDMA Code divis
