CLC/TR 50404:2003
(Main)Electrostatics - Code of practice for the avoidance of hazards due to static electricity
Electrostatics - Code of practice for the avoidance of hazards due to static electricity
This document is a code of practice for avoiding ignition and electric shock hazards arising from static electricity. The processes that most commonly give rise to problems of static electricity are described in detail. They include the handling of solids, liquids, powders, gases, sprays and explosives. In each case, the source and nature of the electrostatic hazard is identified and specific recommendations are given for dealing with them. Basic information about the generation of undesirable static electricity in solids, liquids, gases, explosives, and also on persons, together with descriptions of how the charges generated cause ignitions or electric shocks, is given in the annexes. This document is not applicable to the hazards of static electricity relating to lightning, to damage to electronic components, nor to medical hazards.
Elektrostatika - Pravila ravnanja za izogibanje nevarnostim zaradi statične elektrike
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2003
1DGRPHãþD
SIST R044-001:2002
(OHNWURVWDWLND3UDYLODUDYQDQMD]DL]RJLEDQMHQHYDUQRVWLP]DUDGLVWDWLþQHHOHNWULNH
Electrostatics - Code of practice for the avoidance of hazards due to static electricity
Ta slovenski standard je istoveten z: CLC/TR 50404:2003
ICS:
13.230 Varstvo pred eksplozijo Explosion protection
13.260 9DUVWYRSUHGHOHNWULþQLP Protection against electric
XGDURP'HORSRGQDSHWRVWMR shock. Live working
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
TECHNICAL REPORT CLC/TR 50404
RAPPORT TECHNIQUE
TECHNISCHER BERICHT June 2003
English version
Electrostatics -
Code of practice for the avoidance of hazards
due to static electricity
This Technical Report was approved by CENELEC on 2003-04-19.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Czech Republic,
Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta,
Netherlands, Norway, Portugal, Slovakia, 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
© 2003 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TR 50404:2003 E
Foreword
This CENELEC code of practice gives information about the product and process properties necessary
to avoid electrostatic hazards as well as operational requirements to be written in the users manual to
ensure safe use of the product or process. It can be used in a risk assessment of electrostatic hazards
or for the preparation of product family or dedicated product standards for machines (i.e. type C
standards in CEN, as defined in EN 414:1992, 3.1).
This CENELEC document is based on a number of documents including two national Codes of
Practice: from the UK, BS 5958: Parts 1 & 2:1991, Control of undesirable static electricity; and from
Germany, ZH 1/200: October 1989, Code of Practice for preventing risks of ignition due to electrostatic
charges: Guidelines in static electricity, and a document published by Shell International Petroleum:
Static electricity - Technical and safety aspects. It gives the best available accepted state of the art
guidance for the avoidance of hazards due to static electricity.
This document is mainly written for designers of processes, manufacturers and test houses.
Appropriate information about the procedures necessary to avoid electrostatic hazards shall be written
in the users manual or on the product to ensure safety. This document can also be used by suppliers
of equipment (e.g. machines) when no product family or dedicated product standard exists or where
the existing standard does not deal with electrostatic hazards.
This CENELEC document was originally prepared by the Technical Committee CENELEC TC 44X,
Safety of machinery: electrotechnical aspects. The text of the first edition approved by CLC/TC 44X on
1997-11-07 and its publication was authorised by the CENELEC Technical Board on 1999-01-01.
Following a decision by CENELEC BT, the maintenance of the document was undertaken by the
Technical Committee CENELEC TC 31, Electrical apparatus for explosive atmospheres - General
requirements, which has delegated the revision to its Working Group 20 dealing with electrostatic
hazards.
The text of the draft was submittted to the National Committees for approval by correspondence and was
approved by CENELEC as CLC/TR 50404 on 2003-04-19.
This Technical Report supersedes R044-001:1999.
____________
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Contents
Clause Page
1 Scope. 5
2 Definitions. 5
3 General. 7
3.1 Standard approaches. 7
3.2 Alternative approaches . 8
4 Static electricity in non-conductive solid materials . 8
4.1 General considerations . 8
4.2 Dissipative solid materials. 8
4.3 The use of conductive or dissipative materials in place of non-conductive ones. 9
4.4 Precautions required when using non-conductive solid materials . 9
4.5 Conveyor belts and transmission belts . 12
5 Static electricity in liquids . 13
5.1 General considerations . 13
5.2 Ignition hazard. 14
5.3 Precautions against ignition hazards during liquid handling operations. 15
5.4 Tanks and Containers. 16
5.5 Pipes and hoses for liquids . 31
5.6 Special filling procedures . 34
5.7 Plant processes (blending, stirring, mixing and crystallisation). 36
5.8 Spraying liquids and tank cleaning. 38
5.9 Glass systems. 39
6 Static electricity in gases. 40
6.1 General. 40
6.2 Grit blasting . 41
6.3 Fire extinguishers. 41
6.4 Inerting. 41
6.5 Steam cleaning . 41
6.6 Accidental leakage of compressed gas . 41
6.7 Spraying of flammable paints and powders . 42
6.8 Extraction systems. 42
6.9 Vacuum cleaners, fixed and mobile. 42
7 Static electricity in powders. 43
7.1 General. 43
7.2 Powders in the absence of flammable gases and vapours. 43
7.3 Powders in the presence of flammable gases or vapours . 50
8 Static electricity when handling explosives and electro-explosive devices. 52
8.1 Explosives manufacture, handling and storage . 52
8.2 Handling of electro-explosive devices. 54
9 Static electricity on persons . 55
9.1 General considerations . 55
9.2 Conducting floor. 55
9.3 Dissipative and conductive footwear. 55
9.4 Clothing. 55
9.5 Protective gloves. 56
9.6 Other items. 56
10 Electric shock. 56
10.1 Introduction. 56
10.2 Discharges relevant to electric shock . 56
10.3 Sources of electric shock . 57
10.4 Precautions to avoid electric shocks. 57
10.5 Precautions in special cases. 57
11 Earthing and bonding . 58
11.1 General. 58
11.2 Criteria for the dissipation of static electricity from a conductor. 59
11.3 Earthing requirements in practical systems . 60
11.4 The establishment and monitoring of earthing systems. 62
Annexes
Annex A (informative) Fundamentals of static electricity . 64
Annex B (informative) Electrostatic discharges in specific situations. 73
Annex C (informative) Igniteability properties of substances . 77
Annex D (informative) Classification of hazardous areas. 79
Bibliography. 80
Figures
Figure A.1 - Equivalent electrical circuit for an electrostatically charged conductor. 67
Tables
Table 1 - Restriction on area or width values of non-conductive solid materials in hazardous
areas containing potentially explosive atmospheres of groups IIA, IIB and IIC. 10
Table 2 - Conductivities and relaxation times of some liquids. 14
Table 3 - Precautions for filling large metal tanks with low conductivity liquids. 18
Table 4 - Maximum filling velocities for loading low conductivity liquids other
than petroleum products into road tankers. 22
Table 5 - Vehicles and compartments suitable for high-speed loading for ADR compliant vehicles. 22
Table 6 - Influence of the sulphur content on vd limits for road tankers. 23
Table 7 - Flow rate limits for road tankers . 23
Table 8 - vd and flow rate limits for loading rail tankers with non-petroleum liquids. 24
Table 9 - Flow rate limits for loading rail tankers with petroleum fuels. 25
Table 10 - Use of different types of FIBC . 49
Table 11 - Summary of maximum earthing resistances for the control of static electricity . 62
Table A.1 - Charge build up on medium resistivity powders. 66
Table A.2 - Values of capacitances for typical conductors. 70
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1 Scope
This document is a code of practice for avoiding ignition and electric shock hazards arising from static
electricity. The processes that most commonly give rise to problems of static electricity are described
in detail. They include the handling of solids, liquids, powders, gases, sprays and explosives. In each
case, the source and nature of the electrostatic hazard is identified and specific rec
...
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