GuidelinesfortheCONTROLOFSTATICELECTRICITYININDUSTRYARCHIVEPublishedbytheOccupationalSafetyandHealthServiceDepartmentofLabourWellingtonNewZealandFirstpublished:1982Revised:1990PDFcreatedforwebsite:November1999ARCHIVECONTENTS1.INTRODUCTION.................................................42.GENERALHAZARDSANDPROBLEMS................................43.STATICELECTRICITYINTHEINDUSTRIALCONTEXT................53.1MajorIndustrialSourcesofStatic....................53.2GeneralMeansofControl...............................53.3DiscussionofSpecificControlMeasures...............63.4MaterialsHandlingProblems............................84.HAZARDCONTROLINSPECIALPROBLEMPROCESSESANDINDUSTRIES.114.1LiquidsinMotion.....................................114.2MovingBelts..........................................114.3GasDischarges........................................124.4ElectrostaticPaintandPowderApplication...........124.5CombustibleDusts.....................................134.6Explosives............................................145.ELECTROSTATICCHARGEDETECTION.............................14APPENDIX1:MINIMUMIGNITIONENERGIESFORSOMECOMMONCOMBUSTIBLEVAPOURSANDGASES...............................15APPENDIX2:MINIMUMIGNITIONENERGIESFORSOMECOMBUSTIBLEDUSTCLOUDS......................................16ARCHIVEGUIDELINESFORTHECONTROLOFSTATICELECTRICITYININDUSTRY4ARCHIVE1.INTRODUCTION1.1Staticelectricityisgeneratedbythecontactandseparationofmaterials,andclearlythisgenerationoftencannotbepreventedintheindustrialsetting.Wemustthereforeaimatcontrolmeasuresratherthanexpendenergy,timeandresourcestryingtopreventtheinevitable.1.2Toevaluatethepossibilityofhazardsfromstaticelectricityexistinginanindustriallocalityorinaparticularprocess,itisnecessarytounderstandthecausesandeffectsofthestaticelectricityphenomenon.1.3Matteriscomposedofatomsthatconsistofnegativelychargedelectronscirculatingaboutapositivelychargednucleus.Whenthesurfaceelectronsofamaterialaredisturbed,animbalanceofnegativeandpositivechargesarisesbetweentheinter-actingsurfaces,andresultsinthephenomenonknownasstaticelectricity.Adeficiencyorsurplusofasingleelectronamong100,000atomsissufficienttogiveadetectablestaticchargeonasurface.1.4Surfacedisturbancesleadingtotheformationofastaticchargecanbecausedinseveralwaysbuttheyallinvolvesomekindofmovement.Theycanresultfrominduction,fromthefrictionbetweentwosurfaces,orfromthefirmcontactandsubsequentseparationoftwomaterials.Oneofthematerialsbecomespositivelychargedandtheothernegativelychargedinthemannernotedaboveandanelectricalforceofattractionwillexistbetweenthemsince,ofcourse,unlikechargesattract.1.5Onanearthedconductingmaterial,thechargeflowsawaysorapidlyafterseparationthatitcannotbedetected.However,ifthematerialisanon-conductororaperfectlyinsulatedconductor,theelectricchargecannotleakaway.Asthischargeisunabletoflow,itiscalledstaticelectricity.Itisironicthatstaticelectricityrequiresmovementforgeneration.2.GENERALHAZARDSANDPROBLEMS2.1ThemajorhazardposedbystaticelectricityisthepossibleignitionofflammablevapoursorpowdersandthisproblemisdiscussedinmoredetailinSection2.4below.2.2Additionalhazardsaretheproductionofunexpectedshocksinhumansthatmightresultininjurycausedbyinvoluntaryreflexaction,andthepossibilitythatfalsereadingswillbeinducedinsensitiveinstrumentswherestaticispresent,Thesehazardsmaybelesssignificantwhe...
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