BS 6657:2002 2003
$215.11
Assessment of inadvertent initiation of bridge wire electro-explosive devices by radio-frequency radiation. Guide
| Published By | Publication Date | Number of Pages |
| BSI | 2003 | 94 |
This British 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 initiation. 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 similar 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:
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air bag igniters for automotive applications (including the igniters before they are fitted);
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special pyrotechnic devices;
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pyromechanisms;
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igniters for fireworks;
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special military devices;
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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.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 1 | BRITISH STANDARD |
| 2 | Committees responsible for this British�Standard |
| 3 | Contents |
| 7 | Introduction 1 Scope 2 Normative references 3 Terms and definitions 3.1 duty cycle 3.2 electro-explosive device (EED) 3.3 hazard |
| 8 | 3.4 safe distance 3.5 no-fire energy/power/voltage/current 3.6 round of charges (shot) 3.7 toe shot 3.8 hazard area 3.9 hazard threshold 3.10 exploder 3.11 equivalent isotropically radiated power (EIRP) 3.12 effective field strength 3.13 antenna gain |
| 9 | 3.14 far field 3.15 near field 3.16 leading wire resistance 3.17 bridge wire resistance 3.18 safety resistor 4 Symbols and abbreviations 4.1 Modulation codes 4.2 Polarization codes |
| 10 | 5 General considerations 5.1 Radio-frequency hazard 5.2 Philosophy of the systematic method of approach |
| 11 | 5.3 Responsibility for making the hazard assessment 5.4 Recommended practices for radio silence in offshore operations 6 Transmitters and transmitter output parameters 6.1 Types of transmitters 6.2 Frequency range |
| 12 | 6.3 Transmitter output power 6.4 Antenna gain 6.5 Modulation factors |
| 13 | 7 Circuits for blasting and well perforation 7.1 General 7.2 Typical blasting circuit layouts |
| 14 | Figure 2 Typical single extended line blasting circuits (plan view) Typical multiple extended line blasting circuits (plan view) |
| 15 | Figure 3 Quarry blast including toe shots |
| 16 | Figure 4 Multilevel series-in-parallel demolition blast 7.3 Circuits formed during well-perforating using wireline |
| 17 | Figure 5 Layout of wireline cable for offshore and land based operations |
| 19 | 8 Electro-explosive devices 8.1 General 8.2 Commercial EED Figure 6 Section through a typical commercial instantaneous EED |
| 20 | Table 1 Typical d.c. data on EED 8.3 EED hazard threshold |
| 21 | 8.4 Common mode operation 9 Methods of assessment for determining potential RF ignition hazards on a site where EED are used 9.1 General |
| 22 | Flow diagram for hazard assessment for sites situated on land |
| 23 | Flow diagram for hazard assessment on offshore drilling platforms |
| 24 | 9.2 Basis of the theoretical assessments for land sites |
| 25 | Minimum safe distances for commercial EEDs |
| 26 | Minimum safe distances for commercial EEDs |
| 32 | 9.3 Initial assessment for land sites Minimum distances of safe approach for typical commercial EED |
| 33 | 9.4 Full assessment procedure for land sites |
| 35 | Modulation factors |
| 39 | Field strength versus distance from the transmitter (land path) |
| 40 | Field strength versus distance from the transmitter (sea path) |
| 41 | 9.5 Safe field strength Commercial EED showing winding and overwrapping of leading wires |
| 43 | Safe field strengths for Type I EED (includes the leading wire resistances) |
| 44 | Safe field strengths for Type II EED (includes the leading wire resistances) |
| 45 | Safe field strengths for Type III EED (includes the leading wire resistances) |
| 46 | Safe field strengths for Type IV EED (includes the leading wire resistances) |
| 47 | Safe field strengths for Type V EED (includes the leading wire resistances) |
| 48 | Safe field strengths for Type VI EED (includes the leading wire resistances) |
| 49 | Safe field strengths for Type VII EED (includes the leading wire and safety resistances with a mi… |
| 50 | Safe field strengths for single Type I EED with extended leading wires within 1�m of the ground |
| 51 | Safe field strengths for single Type II EED with extended leading wires within 1�m of the ground |
| 52 | Safe field strengths for single Type III and IV EED with extended leading wires within 1 m of the… |
| 53 | Safe field strengths for single Type V EED with extended leading wires within 1�m of the ground |
| 54 | Safe field strengths for single Type VI EED with extended leading wires within 1�m of the ground |
| 55 | Safe field strengths for Type I EED in typical loop circuits for various perimeter lengths within… |
| 56 | Safe field strengths for Type II EED in typical loop circuits for various perimeter lengths withi… |
| 57 | Safe field strengths for Type III and IV EED in typical loop circuits for various perimeter lengt… |
| 58 | Safe field strengths for Type V EED in typical loop circuits for various perimeter lengths within… |
| 59 | Safe field strengths for Type VI EED in typical loop circuits for various perimeter lengths withi… |
| 60 | Tuning conditions for loop with firing cable |
| 62 | Safe field strengths for a Type VII EED during stages 3 and 5 of well�perforating wireline operat… 9.6 Multiple transmissions |
| 65 | Detuning factor |
| 66 | Detuning factors, |
| 67 | Detuning factors, 9.7 Assessments for offshore drilling operations 10 Practical on-site testing |
| 68 | 11 Safety procedures 11.1 General procedures 11.2 Alternative means of firing 12 Special applications 12.1 Semi-permanent installations 12.2 Flammable hazard situations 12.3 Use of transmitters in mines and quarries |
| 69 | 12.4 Safety in transit |
| 70 | Annex A (informative) Extraction of energy from the electromagnetic field Annex B (informative) Measurement of electromagnetic fields B.1 Range of measurement B.2 Mode of measurement |
| 71 | B.3 Validity of measurement B.3.1 Far field region B.3.2 Near field region B.3.3 Circular and elliptical polarization B.3.4 Measurement errors B.4 Method of measurement |
| 72 | B.5 Characteristics of measuring instruments B.5.1 Field strength measuring receivers |
| 73 | B.5.2 Broad-band detectors Annex C (informative) Sources of information and addresses of advisory bodies |
| 74 | Table C.1 Addresses of some advisory bodies |
| 75 | Annex D (informative) Electromagnetic radiated fields and examples of radiating antennas and unintended r… D.1 Nature of the field D.2 Units of measurement D.3 Examples of antenna characteristics Table D.1 Antennas for vertical polarization for frequencies up to and including 30�MHz |
| 76 | Table D.2 Antennas for horizontal polarization for frequencies up to and including 30�MHz Table D.3 Antennas for frequencies above 30 MHz |
| 77 | Figure D.1 Typical antenna installations (physical characteristics of transmitting antennas) |
| 79 | D.4 Derivation of field strength expressions |
| 80 | Figure D.2 Definition of angles |
| 82 | D.5 Inner limit of the far field Annex E (informative) The effective resistance of the leading wires of an EED Figure E.1 An EED with partly opened leading wires |
| 84 | Figure E.2 An EED with an additional 180° section of line |
| 85 | Table E.1 Ratio of the effective to actual resistance of leading wires |
| 86 | Annex F (informative) Derivation of minimum distances of safe approach for |
| 87 | Annex G (informative) Ground-wave propagation (vertical polarization): calculation of field strength G.1 General |
| 88 | G.2 Field strength calculation G.3 Limitation G.4 Ground conditions |
| 89 | Annex H (informative) Worked examples to demonstrate the effects of antenna gain Annex I (informative) The effects of leading wire resistance, safety resistors and the use of EED with di… I.1 General I.2 Single EED |
| 90 | Figure I.1 Safe field strengths for Type II EED I.3 EED in circuits with extended leading wires or loop circuits |
| 91 | I.4 EED connected to the wireline cable during stages 3 and 5 of well-perforating operations Annex J (informative) Derivation of J.1 General J.2 Figure 12a) J.3 Figure 12e) J.4 Figure 12g) |
