第43卷第4期2023年7月辐射防护RadiationProtectionVol.43No.4July2023HealthPhys.Abstracts,Volume124,Number5AligningExposureLimitsforContactCurrentswithExposureLimitsforElectricFieldsRobertKavet1andRichardA.Tell2(1.KavetConsultingLLC,4455WordenWay,Oakland,CA94619;2.RichardTellAssociates,Inc.,10037LongMeadowRoad,Madison,AL35756.)Abstract:TheInstituteforElectricalandElectronicEngineers(IEEE)andtheInternationalCommissiononNon-ionizingRadiationProtection(ICNIRP)haveestablishedlimitsforexposurestoelectromagneticfieldsacrossthe0-300GHz(non-ionizing)spectrum,includinglimitsoncontactcurrents(CC)specifiedbyIEEEfor0-110MHz(ICNIRPissuedaCC“guidancelevel”).Bothsetsoflimitsseektoprotectagainstpotentiallyadverseeffects,includingaversiveelectrostimulationatfrequencies100kHz.Forthemostpart,CCislinkedtoelectricfield(E-field)exposuresforanungroundedpersoncontactingagroundedobject,withtheshort-circuitcurrent(ISC)throughthecontactpoint(usuallythehand)equivalenttothecurrentthroughthegroundedfeetofafree-standingpersonexposedtoaverticallypolarizedE-field.Thephysicallinkagebetweenthesetwoquantitiesdictatesthattheirrespectiveexposurelimitsalignwithoneanother,whichispresentlynotthecase,especiallywithrespecttofrequenciesfrom100kHzto110MHz.HerewefocusspecificallyonrecommendationsforrevisionstotheIEEEstandard,IEEEStdC95.1TM-2019(“IEEEC95.1”),inwhichtheE-fieldexposurelimit(E-fieldexposurereferencelevels,ERLs)>100kHzinducessubstantiallygreatercurrentsthantheCCERLscurrentlyprescribed.Themostimportantscenariodeservingofattentionconcernsfingercontactthrougha1cm2cross-sectionalinterfacebetweentheskinandagroundedconductorinwhichtherateoftemperatureriseinthepresenceofanE-fieldERLcanberapidenoughtocauseaburninjury.Thisrateishighlydependentonthemoistness/drynessoftheskinatthecontactpoint(i.e.,itsimpedance)—ahighlyvariablevalue—withtemperatureincreasingmorerapidlywithincreasingdryness(greatercontactimpedance).Thetwomainremediestoalleviatethepossibilityofinjuryinthis“touch”scenarioareto(a)limitthetim...
