CLC/TR 50426:2004
(Main)Assessment of inadvertent initiation of bridge wire electro-explosive devices by radio-frequency radiation - Guide
Assessment of inadvertent initiation of bridge wire electro-explosive devices by radio-frequency radiation - Guide
This standard provides guidance in assessing the potential ignition hazard from the inadvertent extraction of energy from electromagnetic fields, propagated from communication, radar or other transmitting aerials to plant where a potentially flammable atmosphere may be present. The standard is not concerned with similar hazards arising from electromagnetic fields generated by other means, such as electric storms, electricity generating installations or other radiating electrical equipment, nor is it concerned with any hazard arising within telecommunications or oter electronic equipment
Leitfaden zur Verhinderung des unbeabsichtigten Auslösens einer Zündeinrichtung mit Brückendraht durch hochfrequente Strahlung
Evaluation de la création par inadvertance de dispositifs électro-explosifs par pont métallique, par rayonnement de radiofréquence - Guide
Ugotavljanje nenamernega radiofrekvenčnega proženja elektroeksplozivnih naprav - Vodilo
General Information
Standards Content (Sample)
SLOVENSKI SIST-TP CLC/TR 50426:2005
STANDARD
april 2005
Ugotavljanje nenamernega radiofrekvenčnega proženja elektroeksplozivnih
naprav - Vodilo
Assessment of inadvertent initiation of bridge wire electro-explosive devices by
radio-frequency radiation – Guide
ICS 13.230; 29.260.20 Referenčna številka
© Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno
TECHNICAL REPORT CLC/TR 50426
RAPPORT TECHNIQUE
TECHNISCHER BERICHT December 2004
ICS 13.230; 29.260.20; 33.060.20
English version
Assessment of inadvertent initiation of bridge wire
electro-explosive devices by radio-frequency radiation –
Guide
Evaluation de la création Leitfaden zur Verhinderung
par inadvertance de dispositifs des unbeabsichtigten Auslösens
électro-explosifs par pont métallique, einer Zündeinrichtung mit Brückendraht
par rayonnement de radiofréquence – durch hochfrequente Strahlung
Guide
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, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia,
Spain, Sweden, Switzerland and United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: 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
Foreword
This Technical Report was prepared by the Technical Committee CENELEC TC 31, Electrical apparatus for
explosive atmospheres - General requirements.
The text of the draft 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 considerations . 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 transmitters. 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 well 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 wireline . 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
9.2 Basis of the theoretical 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 Procedure. 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-perforating 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 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 (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 radiating 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 (vertical 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 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 currents 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 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 concerned 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
physical electrical parameters of various types of EED.
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 the 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
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 European Technical 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 9 GHz to 60 GHz are based on extrapolation of data for frequenc
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.