Ministry of Defence
Defence Standard 21-3 (NES 1003)
Issue 1 Publication Date 1 April 2000
The Requirement for Assessing . Transient
Coupled Energy into Stores Containing
Electro-Explosive Devices (EED)
Incorporating NES 1003 Category
Issue 2 Publication Date January 1993
This NES Supersedes
NES 1003 ISSUE 1
Record of Amendments
AMDT INSERTED BY DATE
10
NAVAL ENGINEERING STANDARD 1003
ISSUE 2
THE REQUIREMENT FOR
ASSESSING TRANSIENT COUPLED ENERGY INTO STORES
CONTAINING ELECTRO-EXPLOSIVE DEVICES (EED)
The issue and use of this Standard
is authorized on behalf of the
Controller of the Navy by :
Director Combat Systems/Submarines
O CROWN COPYRIGHT 1993
Published by :
Procurement Executive, Ministry of Defence
Sea Systems Controllerate
Foxhill, Bath BA1 5AB
(i)
115-C1622
NES 1003
Issue 2
CONDITIONS OF RELEASE
General
1. This Naval Engineering Standard (NES) has been prepared for the use of the Crown and
of its contractors in the execution of contracts for the Crown and, subject to the Unfair
Contract Terms Act 1977, the Crown will not be liable in any way whatever where the
Standard is used for any other purpose .
2. This document is Crown Copyright and the information herein may be subject to Crown
or third party rights . It is not to be released, reproduced or published without written
permission of the MOD .
3. The Crown reserves the right to amend or modify the contents of this NES without
consulting or informing any holder .
MOD Tender or Contract Process
4. This NES is the property of the Crown and unless otherwise authorized in writing by the
MOD, must be returned on completion of the contract, or submission of the tender, in
connection with which it is issued .
5. When this NES is used in connection with a tender or contract, the user is to ensure that
he is in possession of the appropriate version of each document, including related
documents, relevant to each particular tender or contract .
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CONTENTS
Page
AUTHORIZATION (i)
CONDITIONS OF RELEASE (ii)
CONTENTS (iii)
INTRODUCTION (iv)
SECTION 1 SCOPE 1
SECTION 2 HEALTH AND SAFETY WARNING 1
SECTION 3 RELATED DOCUMENTS 1
SECTION 4 DEFINITIONS AND ABBREVIATIONS 2
SECTION 5 ARMAMENT STORES WITHIN ARMAMENT DEPOTS 3
SECTION 6 ARMAMENT STORES INSTALLED ON HM VESSELS, 4
RFAs AND NAVAL SHORE ESTABLISHMENTS
ANNEX A DECISION TREE TO DETERMINE THE NEED FOR 5
TRANSIENT TESTING FOR ARMAMENT STORES
WITHIN RNADs
ANNEX B DECISION TREE TO DETERMINE THE NEED FOR 7
TRANSIENT TESTING FOR ARMAMENT STORES IN
HM VESSELS, RFAs AND NAVAL SHORE
ESTABLISHMENTS
ALPHABETICAL INDEX 9
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INTRODUCTION
1. This Naval Engineering Standard (NES) is sponsored by the Director General Supplies
and Transport (Naval), (DGST(N)), on behalf of the Director Combat
Systems/Submarines (DCS/SM) . The Point of Contact for matters pertaining to the
technical content of this NES is Directorate of Supplies and Transport (Engineering and
Weapon Support) (DST(EWS), Branch ST64D, PDST(AS) Safety Team .
2. It is to be applied to any Ministry of Defence contract for Naval weapons and their
supporting test systems .
3. Its purpose is to provide criteria for the requirements relating to Electromagnetic
Compatability (EMC) transient testing of explosive armament stores within Armament
Depots and in HM Vessels, RFAs and Naval Shore Establishments .
4. If it is found to be technically unsuitable for any particular requirement the Sponsor is to
be informed in writing with a copy to Director General Submarines (DGSM), Section
SM832.
5. Any user of this NES either within MOD or in industry may propose an amendment to it .
Proposals for amendments that are not directly applicable to a particular contract are to be
made to the Sponsor of the NES and those directly applicable to a particular contract are
to be dealt with using existing procedures or as specified in the contract .
6. No alteration is to be made to this NES except by the issue of an authorized amendment .
7. Unless otherwise stated, reference in this NES to approval, approved, authorized or
similar terms, means by the Ministry of Defence in writing .
8. Any significant amendments that may be made to this NES at a later date will be
indicated by vertical side lines . Deletions will be indicated by 000 appearing at the end
of the line intervals .
9. When NES are incorporated into contracts users are responsible for their correct
application and for complying with contract and any statutory requirements . Compliance
with an NES does not of itself confer immunity from legal obligations .
10. This NES has been reissued to :
a. include reference to transient trial assessment on HM Vessels, RFAs and in Naval
Shore Establishments .
b. include reference to insensitive devices .
c. correct errors on the RNAD decision tree .
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1. SCOPE
0101 . This NES is concerned with assessing the possibility of the inadvertent initiation of
electro-explosive devices (EED) within weapons or other explosively configured stores,
whilst they are under test within Royal Naval Armament Depots (RNAD) or as part of an
installation aboard HM Vessels, RFAs or in Naval Shore Establishments .
0102 . Only the hazards arising from transient coupled energy into EED firing circuits are
addressed herein ; possible hazards to EED arising from intentional radio frequency (rf)
emissions are dealt with in BR 2924 and its addendum CB 4986 for weapons in Naval
Service and BR 1029 Volume 6 Annex 5 .8 for weapons within RNADs .
2. HEALTH AND SAFETY WARNING
0201 . Warning
This NES calls for the use of processes, substances and/or procedures that may be
injurious to health if adequate precautions are not taken . It refers only to technical
suitability and in no way absolves either the supplier or the user from statutory
obligations relating to health and safety at any stage of manufacture or use .
CAUTION INJURY OR DAMAGE TO HEALTH MAY BE CAUSED BY
CONTACT WITH HAZARDOUS VOLTAGES, BREAKDOWN OF
INSULATION OR LEAKAGE OF CURRENTS .
CAUTION INJURY OR DAMAGE MAY BE CAUSED BY HAZARDS
DIRECTLY LINKED TO FIRE AND EXPLOSION
3. RELATED DOCUMENTS
0301 . Reference is made to :
See Clause
BR 1029 - Regulations for the RNSTS - Armaments General 0102
Volume 6
BR 2924 - Radio Hazards in Naval Service 0102
CB 4986 - Confidential Addendum to BR 2924 0102
Ordnance Board Pillar Proceeding 101(1) - Principles of Design 0401
and Use for Electrical Circuits Incorporating Explosive Components
0302 . Related documents may be obtained as follows :
a. British Standards British Standards Institution
Linford Wood, Milton Keynes
MK14 6LE
b. Defence Standards Directorate of Standardization and Safety Policy,
Stan 1, Kentigern House,
65 Brown Street,
Glasgow G2 8EX
c. Naval Engineering Standards - MOD Library Services (Bath)
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d. Other Documents - Tender or Contract sponsor to advise .
MOD Library Services (Bath), Foxhill, Bath, BA1 5AB can advise in cases of difficulty .
0303 . All applications to Ministry Establishments for related documents are to quote the
relevant MOD Invitation to Tender or Contract number and date, together with the
sponsoring Directorate and the Tender or Contract Sponsor .
4. DEFINITIONS AND ABBREVIATIONS
0401 . For the purpose of this NES the following definitions apply :
Electro-Explosive a one-shot explosive or pyrotechnic device used as the
Device (EED) initiating element in an explosive or mechanical train, and
which is activated by the application of electrical energy .
Electromagnetic the ability of electrical and electronic equipment, sub
Compatability (EMC) systems and systems to share the electromagnetic spectrum
and perform their desired functions without unacceptable
degradation from or to the specified electromagnetic
environment .
Electromagnetic degradation of the performance of a device, equipment or
Interference (EMI) system caused by an electromagnetic disturbance .
EMC Transient Trial a document which gives the procedure required to carry out
Test Plan the measurement of transient coupled energy induced in
EED circuits, listing those operations which have been
agreed with the equipment sponsors, as being worthy of
inclusion, the test instrumentation to be used and the
acceptance criteria.
Equipment any electrically powered equipment, either Test Equipment
or Installed Plant .
Exploding a high voltage EED in which the dissipation of 0 .25J of
Bridge-wire (EBW) energy in a period of less than 1us causes a bridge-wire to
explode inducing a detonation within explosives placed in
contact with it .
Exploding Foil also known as Slapper Detonators, in which the dissipation
Initiators (EFI) of pulsed energy, similar to that of an EBW causes a foil to
explode, propelling a small plate across a space before
impacting and detonating an explosive charge .
No Fire Threshold the value of power or current at which the probability of
firing of an EED is 0.1% at the 95% single sided lower
limit of confidence in accordance with Ordnance Board
Pillar Proceeding 101(1) .
Weapon any Naval Armament Store which contains EED or could
be susceptible to electromagnetic interference (EMI) due to
either its components or its design .
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0402 . For the purposes of this NES the following additional abbreviations apply :
CC Conducting Composition
FOC First of Class
rf radio frequency
5. ARMAMENT STORES WITHIN ARMAMENT DEPOTS
0501 Whenever an armament store containing an EED, (or any of its sub-assemblies
containing an EED) is in an RNAD, inadvertent initiation could occur if the induced
electromagnetic energy from other electrical services/equipments is of sufficient
magnitude . The efficiency of coupling this energy into the EED wiring depends largely
on the configuration of the wiring itself, with single-pole connected (using the structure
of the store as the firing circuit return path) highly sensitive EED such as Conducting
Composition (CC) devices being most at risk .
0502 . Tests on EED firing circuits are only to be carried out using test equipment approved by
the PDST(AS) Safety Team . However, there is the possibility that transient coupling to
the test equipment leads may take place, and consideration of these leads needs to be
included in the assessment .
0503 . Switching transients in the test equipment, other building services and equipments,
particularly where inductive circuits are associated, pose a credible hazard .
0504. A decision tree, (shown at Annex A), is to be used as a guideline to determine the need
for transient testing for each EED . If, as a result of using the decision tree, transient
testing is considered appropriate, it will be necessary to arrange that :
a. a suitably instrumentable weapon is supplied by the Contractor and the trial is
carried out to the agreed EMC Transient Trial Test Plan .
b. the test subject and its EED wired configuration is fully representative of the
wiring configuration which will be used during scheduled processing.
0505 . The levels are to be measured during an EMC transient trial on the particular weapon,
instrumented to record the highest transient energy during the test sequence, whilst
ancillary equipment in the area (cranes, other services, safety and monitoring equipment
etc) is operated .
0506 . The acceptable level of transient coupled energy is usually expressed as a number of dB
(7, 10 or 13) below the 'no fire threshold' level for the particular type of EED . The level
is dependent upon the type of EED, and the degree of confidence in its characterization .
The actual margin of safety is to be agreed between the Weapon Equipment Sponsor or
the nominated Safety Advisor .
0507 . The EMC Transient Trial Test Plan, which is usually produced by the Contractor,
contains a list of the equipment to be operated during EMC transient trial testing . This
list is to be agreed at the outset with the Weapon Equipment Sponsor, or his nominated
Safety Advisor.
0508 . Transient testing may need to be repeated if:
a. a change in the test environment or installation might lead to less benign
conditions, and the hazard needs to be re-quantified .
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b. a Safety Study, or other trial report on a particular armament store suggests that it
may be more vulnerable than previously considered .
6. ARMAMENT STORES INSTALLED ON HM VESSELS, RFAs AND NAVAL
SHORE ESTABLISHMENTS
0601 . As in Armament Depots, there is a possibility that EED in an installed armament store
may be hazarded due to transient coupled energy from the proximity of adjacent electrical
services .
0602 . It is a contractual requirement to assess First of Class (FOC) weapon installations for the
possibility of transient coupled energy and thus the decision tree shown at Annex B is to
be applied . If, after the application of the decision tree it shows that transient trials are
required then it will be necessary to arrange that :
a. a suitably instrumented weapon is supplied by the Contractor and the trial is
carried out to the agreed Transient Trial Test Plan ;
b. the test subject and its EED wired configuration is considered to be fully
representative of the wiring configuration of the installed armament store .
0603 . Annex B is intended to be used only as a guide as to when transient trials are indicated .
An examination of actual wiring runs etc, should be made, and any services that could
appear to be marginal included in the trials schedule.
0604 . The Transient Trial Test Plan, which is usually produced by the Contractor, contains a list
of those services to be energized during EMC transient trial testing . This list is to be
agreed at the outset with the Weapon Equipment Sponsor, or his nominated Safety
Advisor.
0605 . The acceptable level of transient coupled energy is the same as that for testing within
Armament Depots (see clause 0506).
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DECISION TREE TO DETERMINE THE NEED FOR TRANSIENT TESTING OF ARMAMENT STORES WITHIN AN RNAD NES 1003
Issue 2
ANNEX A
DECISION TREE TO DETERMINE THE NEED FOR TRANSIENT TESTING NES 1003
OF ARMAMENT STORES IN HM VESSELS, RFAs AND NAVAL SHORE ISSUE 2
ESTABLISHMENTS
A0161 7 ANNEX B
NES 1003
Issue 2
8
ANNEX B
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ALPHABETICAL INDEX
Conducting Composition 0501, Annex A
Decision Trees 0504, 0602, Annex A, Annex B
Electro-explosive device 0101, 0102, 0401
0501, 0502, 0504
0506, 0601, 0602
Annex A, Annex B
EMC Transient Trial 0505, 0507, 0602
0603, 0604
EMC Transient Trial Test Plan 0401, 0504, 0507
0602, 0604
Exploding Bridge wire 0401, Annex A, Annex B
Exploding Foil Initiators 0401, Annex A, Annex B
First of Class- 0602
PDST(AS) Safety Team 0502
Radio frequency emissions 0102
Safety Advisor 0506, 0507, 0604
Switching transients 0503
Test Equipment 0502
Threshold levels 0506
Transient coupled energy 0102, 0401, 0502
0506, 0605
Transient testing 0504, 0508
Weapon Sponsor 0506, 0507, 0604
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Inside Rear Cover
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