Atex.stat.Glor Static Electricity Iss

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<ul><li><p>Systematic Assessment of Ignition Hazard Satic Electricity</p><p>Dr. Martin GlorSwiss Institute for the Promotion of Safety and Security, </p><p>Switzerland</p><p>www.swissi.ch</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 2</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 3</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 4</p><p>Zones and Ignition Sources (ATEX)Assessment of the probability of explosions Coincidence in space and time of</p><p> Explosive atmosphere Effective ignition source</p><p>Effectiveness</p><p>Fuel</p><p>Ignition Source</p><p>Oxyg</p><p>en</p><p>Coincidence</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 5</p><p>Zones and Ignition Sources (ATEX)</p><p>explosive atmosphere </p><p>ignition source </p><p>Zone 2,22 </p><p>Zone 1,21 </p><p>Zone 0,20 </p><p>during normal operation </p><p>no no no </p><p>from time to time yes no no </p><p>seldom yes yes no </p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 6</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 7</p><p>Charge Build-up in Industrial Processes</p><p>Most frequent charging mechanismsContact and frictional charging </p><p> (tribo charging) solids, granules, powders</p><p>++++ +</p><p>++ +</p><p>_</p><p>_</p><p>_</p><p>_</p><p>_</p><p>_</p><p>_</p><p>_</p><p>++ ++</p><p>+</p><p>- --</p><p>- -</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 8</p><p>Charge Build-up in Industrial Processes</p><p>Most frequent charging mechanismsDouble layer charging</p><p> liquids, suspensions, emulsions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 9</p><p>Charge Build-up in Industrial Processes</p><p>Most frequent charging mechanisms Induction charging</p><p> conductive objects exposed to electrical fields</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 10</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 11</p><p>Basic Scheme of Static Electricity</p><p>charge separation</p><p>chargedissipation</p><p>chargedissipation</p><p>charge accumulationon equipment etc.</p><p>charge accumulationon product</p><p>discharge</p><p>ignition</p><p>explosive atmosphere</p><p>discharge</p><p>ignition</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 12</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 13</p><p>Flammable Liquids, Suspensions and Emulsions Is all conductive equipment properly</p><p>earthed? Are all conductive parts of equipment properly </p><p>earthed? Are there insulating gaskets or fittings? Do such gaskets or fittings prevent earthing </p><p>and bonding of conductive parts? Are there insulating coatings or paintings? Do such coatings or paintings prevent</p><p>earthing and bonding of conductive parts? Is the personnel properly earthed? Are all conductive mobile parts as well as all </p><p>conductive packaging (containers, bags, etc.) and auxiliary devices properly earthed during transfer?</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 14</p><p> Is any equipment or parts of it made from insulating material?</p><p> Can this be tolerated with respect to the zoning and the explosion group as well as with respect to the size of the insulating areas?</p><p> Are there insulating coatings or paintings? Can these be tolerated with respect to the </p><p>zoning and the explosion group as well as with respect to their thickness and possible charging mechanisms?</p><p> Are there used insulating packaging and auxiliary devices?</p><p> Can these be tolerated with respect to the zoning and the explosion group as well as with respect to their size?</p><p>Flammable Liquids, Suspensions and Emulsions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 15</p><p> What is the conductivity of the liquid? Are the limits for the filling velocity</p><p>depending on liquid conductivity, pipe diameter and tank size met in case of pure liquids?</p><p> In case of suspensions or emulsions of low or medium conductivity: Is the tank inerted or has there been made a comprehensive assessment of electrostatic ignition hazards?</p><p> Is the liquid of high viscosity? In this case the charge build-up may be very high and a special hazard assessment is required.</p><p> Are there performed washing or cleaning operations with high pressure liquid jets? In this case special guidance is recommended.</p><p>Flammable Liquids, Suspensions and Emulsions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 16</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 17</p><p>Gases and Vapours Pure gases and vapours do not become charged However, as soon as gases or vapours contain even </p><p>small amounts of droplets or particles these may become highly charged.</p><p> This becomes obvious e.g. during the release of high pressure oversaturated water vapour.</p><p> Depending on the nature of the gas or the vapour the recommendations for liquids and/or powders should be considered.</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 18</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 19</p><p>Hybrid Mixtures A hybrid mixture is commonly defined as a mixture of </p><p>flammable gases or vapours in combination with flammable powders.</p><p> From the point of view of an ignition hazard due to static electricity, hybrid mixtures require special precautions:</p><p>- Charge build-up may be as high as for pure powders.</p><p>- Minimum ignition energy may be as low as for pure gases or vapours.</p><p> Special guidance or expert advice is recommended.</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 20</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 21</p><p>Flammable Powders and Wet Cakes Is all conductive equipment properly</p><p>earthed? Are all conductive parts of equipment properly </p><p>earthed? Are there insulating gaskets or fittings? Do such gaskets or fittings prevent earthing </p><p>and bonding of conductive parts? Are there insulating coatings or paintings? Do such coatings or paintings prevent</p><p>earthing and bonding of conductive parts? Is the personnel properly earthed? Are all conductive mobile parts as well as all </p><p>conductive packaging (containers, bags, etc.) and auxiliary devices properly earthed during transfer?</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 22</p><p> Is any equipment or parts of it made from insulating material?</p><p> Can this be tolerated with respect to the zoning?</p><p> Are there insulating coatings or paintings? Can these be tolerated with respect to the </p><p>zoning as well as with respect to their thickness and possible charging mechanisms?</p><p> Are there used insulating packaging and auxiliary devices?</p><p> Can these be tolerated with respect to the zoning, the minimum ignition energy and the particle size distribution of the powder as well as with respect to their size?</p><p>Flammable Powders and Wet Cakes</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 23</p><p> What is the resistivity of the bulked powder? In case of high resistivity powder: Do </p><p>incendive cone discharges have to be expected? This depends on the resistivity, the particle size distribution and the minimum ignition energy of the powder as well as on the silo diameter and the way and rate of filling (see guidelines or ask experts for advice).</p><p> Are silos with a diameter larger than 3 m filled?</p><p> Does the powder contain more than 0.5%w/w of a flammable solvent?</p><p> Are there performed any further diminution processes?</p><p>Flammable Powders and Wet Cakes</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 24</p><p>Flammable Powders and Wet Cakes</p><p> In case of handling low minimum ignition energypowders in large amounts in plants of high complexity:</p><p> Are you sure that you can reliably ensure earthing and bonding of all your equipment and personnel?</p><p> The only application of the safety measure Avoidance of Effective Ignition Sourcesmay be very difficult.</p><p> Consider additional measures of explosion prevention or protection</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 25</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Flammable Liquids, Suspensions and Emulsions Flammable Gases and Vapours Hybrid Mixtures Flammable Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 26</p><p>Guidelines and Codes of Practice</p><p> CENELEC Technical Report CLC/TR 50404 Electrostatics - Code of practice for the avoidance of hazards due to static electricity, June 2003.</p><p> BGR 132 Vermeiden von Zndgefahren infolge elektrostatischer Aufladungen, Hauptverband der gewerblichen Berufsgenossenschaften, Fachausschuss Chemie der BGZ, 2004.</p><p> Expertenkommission fr Sicherheit in der Chemischen Industrie der Schweiz (ESCIS) Heft Nr.2 Static Electricity Rules for Plant Safety , revised2nd Edition, January 2005.</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 27</p><p>Contents</p><p> General Approach Zones and Ignition Sources (ATEX) Charge Build-up in Industrial Processes Basic Scheme of Static Electricity</p><p> Handling and Processing of Liquids, Suspensions and Emulsions Gases and Vapours Hybrid Mixtures Powders and Wet Cakes</p><p> Guidelines and Codes of Practice Summary and Conclusions</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 28</p><p>Summary and Conclusions</p><p>Is there a classified area?</p><p>Is the personnel earthed RE &lt; 100 MOhm?</p><p>Are all conductive parts earthed RE &lt; 1 MOhm?</p><p>Is all equipment including auxiliary devices and packaging, etc. made from conductive material?</p><p>Can equipment, etc. made from insulating material be tolerated with respect to the substances handled and processed as well as with respected to the zoning?</p><p>yes</p><p>Exchange equipment</p><p>Earth all conductive parts of equipment</p><p>no</p><p>Earth personnelno</p><p>yes</p><p>yes</p><p>no no</p><p>no No explosion hazard exists</p><p>yesyes</p><p>Short decision tree details have to be taken from guidelines</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 29</p><p>Are there insulating coatings or paintings?</p><p>no</p><p>Can these insulating coatings or paintings be tolerated with respect to the substances handled and processed as well as with respected to the zoning?</p><p>Remove or modify coatings or paintings</p><p>yes</p><p>no</p><p>Ensure earthing and bonding of all conductive parts</p><p>yes</p><p>Are there insulating gaskets, fittings, etc.?</p><p>no</p><p>Ensure earthing and bonding of all conductive parts</p><p>yes</p><p>No electrostatic ignition hazards associated with incendive discharges from equipment, packaging and personnel have to be expected.</p><p>Summary and ConclusionsShort decision tree details have to be taken from guidelines</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 30</p><p>Take additional measures of explosion prevention and/or protection.</p><p>Are there handled flammable liquids, suspensions or emulsions?</p><p>no</p><p>Assess occurrence and incendivity of discharges associated with liquids, suspensions, emulsions, mists, droplets, etc.</p><p>yes</p><p>no</p><p>Can the occurrence and incendivity of discharges be tolerated with respect to the substances handled and processed as well as with respect to the zoning?</p><p>yes</p><p>Summary and ConclusionsShort decision tree details have to be taken from guidelines</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 31</p><p>Are there handled granules, powders, dusts or hybrid mixtures?</p><p>No electrostatic ignition hazards associated with incendive discharges from the substances handled and processed have to be expected.</p><p>yesAssess occurrence and incendivity of discharges associated with granules, powders, dusts, hybrid mixtures, etc.</p><p>Take additional measures of explosion prevention and/or protection.</p><p>no</p><p>Can the occurrence and incendivity of discharges be tolerated with respect to the substances handled and processed as well as with respect to the zoning?</p><p>yes</p><p>no</p><p>Summary and ConclusionsShort decision tree details have to be taken from guidelines</p></li><li><p>Dr. Martin Glor Systematic Assessment of Ignition Hazard Static Electricity 32</p><p> This Presentation gives guidance to identify the most frequently encountered electrostatic ignition hazards in the process industry</p><p> It is far from being comprehensive</p><p> Details should be taken from existing guidelines and codes of practice</p><p> In case of further questions expert advice is strongly recommended</p><p>Summary and Conclusions</p></li></ul>