PDCENTR16148-2011

PDCEN/TR16148:2011BSIStandardsPublicationHeadandneckimpact,burnandnoiseinjurycriteriaAGuideforCENhelmetstandardscommitteesPDCEN/TR16148:2011PUBLISHEDDOCUMENTNationalforewordThisPublishedDocumentistheUKimplementationofCEN/TR16148:2011.TheUKparticipationinitspreparationwasentrustedtoTechnicalCommitteePH/6,Headprotection.Alistoforganizationsrepresentedonthiscommitteecanbeobtainedonrequesttoitssecretary.Thispublicationdoesnotpurporttoincludeallthenecessaryprovisionsofacontract.Usersareresponsibleforitscorrectapplication.BSI2011ISBN9780580718656ICS13.340.20CompliancewithaBritishStandardcannotconferimmunityfromlegalobligations.ThisPublishedDocumentwaspublishedundertheauthorityoftheStandardsPolicyandStrategyCommitteeon30June2011.AmendmentsissuedsincepublicationDateTextaffectedTECHNICALREPORTRAPPORTTECHNIQUETECHNISCHERBERICHTICS13.340.20PDCEN/TR16148:2011CEN/TR16148March2011EnglishVersionHeadandneckimpact,burnandnoiseinjurycriteria-AGuideforCENhelmetstandardscommitteesCritresrelatifsautraumatismecervico-facialetauxlsionsduesauxbrluresetaubruit-GuidedestinauxcomitsdesnormessurlescasquesdeprotectionduCENKriterienfrVerletzungendurchEinwirkungaufKopfundHals,VerbrennungenundLrmverletzungen-LeitfadenfrArbeitsgruppen,dieeuropischeHelmnormenerarbeitenThisTechnicalReportwasapprovedbyCENon27December2010.IthasbeendrawnupbytheTechnicalCommitteeCEN/TC158.CENmembersarethenationalstandardsbodiesofAustria,Belgium,Bulgaria,Croatia,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France,Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal,Romania,Slovakia,Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom.2011CENEUROPEANCOMMITTEEFORSTANDARDIZATIONCOMITEUROPENDENORMALISATIONEUROPISCHESKOMITEEFRNORMUNGManagementCentre:AvenueMarnix17,B-1000BrusselsAllrightsofexploitationinanyformandbyanymeansreservedworldwideforCENnationalMembers.Ref.No.CEN/TR16148:2011:EPDCEN/TR16148:2011CEN/TR16148:2011(E)ContentsPageForeword.3Introduction.412344.14.255.15.26788.18.29AnnexA.1A.2A.3A.4A.5A.6A.7Abbreviatedinjuryscale,AIS.5Peaklinearacceleration(A.3.1&A.4).9HeadinjurycriterionHIC(A.4).9Rotationalmotion(A.2.6,A.3.2&A.4.3).10PeakRotationalAcceleration.10Tangentialforceatthehelmetsurface.10Skullcrushingandpenetrationforce(A.2.2&A.3.3).11Crushingforce.11Penetrationforce.11Neckinjury.11Noise(AppendixsectionA5.0).12Heat:burnsandfatigue(A.6).12Burns.12Heatfatigue.13References.14ABiomechanicsofheadinjuryfromimpact,noiseandheat.15General.15Headinjuries.16Headinjurymechanisms.24Headinjurycriteria.29Noise.31Heat:burnsandfatigue.35Conclusions.41Bibliography.422PDCEN/TR16148:2011CEN/TR16148:2011(E)ForewordThisdocument(CEN/TR16148:2011)hasbeenpreparedbyTechnicalCommitteeCEN/TC158“Headprotection”,thesecretariatofwhichisheldbyBSI.Attentionisdrawntothepossibilitythatsomeoftheelementsofthisdocumentmaybethesubjectofpatentrights.CENand/orCENELECshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights.3PDCEN/TR16148:2011CEN/TR16148:2011(E)IntroductionMembersofhelmetStandardscommitteesfrequentlyneedtodefinelimitsfortestprocedures.Suchlimitsrelatetotestvaluesthatindicatethepotentialforinjuryandyetitisoftendifficultformemberstoknowthetypeandseverityofinjurythatisrepresentedbyagiventestvalue.Overtheyears,criteriahavebeendevelopedfordifferentbodyregionsandusuallythesehavebeenderivedfromacombinationofaccidentandcasualtydata,andtestsoncadavers,cadaverbodyparts,animalsandhumanvolunteers.However,suchcriteriaareoftenusedbytheautomotiveindustryaspass/failvalueswithoutaclearunderstandingofhumantolerancetoinjuriousforces.Thissometimesleadstothemistakenbeliefthatanyvaluebelowthestatedlimitimpliesuninjuredandallvaluesaboveimplyaseriousorfatalinjury.Thismisconceptiongivesverylittlefreedomtochoosevaluesthataredifferentfromtheofteninappropriateautomotivevalue.Thisisparticularlytrueforheadinjurycriteriaforwhichvaluesforahelmetedheadmaybedifferenttothosefortheunhelmetedhead.Manyaccidentstowearersofhelmets,whichcoverawiderangeofactivitiesfromhorseridingtodownhillskiing,resultinaclosedheadinjury.Thisiswhenthebrainisdamagedwithoutanyskullorexternaltissuedamage.Conversely,headinjuriesinautomotiveaccidentsaremuchmorefrequentlyopenheadinjurieswithskullfractureandsofttissuelesions.Othermisconceptionsarisebecauseofthefailuretounderstandthathumanresponsetoagivendoseorinjuriousparametervariesacrossarangeofthepopulation.ThedoseresponsecurvetendstobeS(sigmoid)shapedsuchthatasthemagnitudeoftheinjuriousparameterincreasessodoesthepercentofthepopulationthatsustainsaninjuryofagivenseverity.Thus,afamilyofScurvescanbegeneratedforarangeofinjuryseveritysuchasAISandameasurementorcriterionsuchasHIC,theHeadInjuryCriterion.Unfortunately,thedataforsuchananalysisisgenerallydifficulttoobtainbecausemeasurementsgeneratedbytestapparatusdonotrelatedirectlytoinjuryseveritybecauseaheadformforexampledoesnotrespondinanimpactlikeahumanhead.Hence,itisnecessarytofindarelationshipbetweenthesetestmeasurementsandinjuryseverity.Thispaperisdesignedtoprovideinformationtoconvenorsthatwillhelpinchoosingtestlimitsinrelationtoaparticularinjurytypeandseverity.ItisworthnotingthataccidentinvestigatorsuseascaleknownastheAbbreviatedInjuryScale,AIS(AAAM).Thiswasdeveloped(intheUSA)sothatinjuryseveritycouldberecordedindatabasesregardlessofthebodyregionandtypeofinjurythusavoidinglengthymedicaltermsthatwereunfamiliaranddifficulttointerpret.ThispaperbeginsbyreviewingtheAISscaleanditsapplicationtoheadandneckinjuriesandburninjuries.Thereafter,eachmeasurementtypeisreviewedandtheseverityofinjuryforgivenvaluesisidentifiedwherepossible.AsectiononburninjuriesandfatiguerelatedtoheatexposurehasbeenincludedtoassistwithStandardsforequipmenttoprotectfirefighters.TheAppendixdescribestheskinstructureandthecategoryandconsequenceofburninjuries.Prematuredeafnessbecauseofhighnoiselevelsandtheconverseproblemofoverattenuationofauditorywarningswasalsoconsidered.SuggestedlevelshavebeenincludedwithdetailsoftestmethodsinAnnexA.4PDCEN/TR16148:2011CEN/TR16148:2011(E)1Abbreviatedinjuryscale,AISThisisascalethatextendsfrom0to6where0isuninjuredand6isunsurviveable.EachlevelcanbeappliedtoanybodyregionaccordingtoacodingmanualdevelopedbytheAssociationfortheAdvancementofAutomotiveMedicine(AAAM).Tables1and2givethescaleandinjuryseverityandanindicationoftheheadandneckinjuriesthatwouldbeclassifiedateachlevel.Table3givessimilarinformationforburninjuriesbydegree,surfaceareaandregionofthebody.5AIS0uninjuredAIS1minorAIS2slightAIS3moderateAIS4seriousAIS5severeAIS6unsurviveableScalpsuperficialabrasions,contusions,lacerationsXmajorlacerationorminorbloodlossXbloodloss20%ortotalscalplossXIntracranialvessels(arteries)lacerationXXCranialnervescontusion,laceration,lossoffunctionXBrainswelling,contusions,haemorrhageXhaematoma,large15cccontusionXmassive30cccontusions,diffuseaxonalinjury,largehaematomaXcrush,penetratinginjuryXLossofconsciousness1hourX1-6hoursor24hours,or6-24hourswithneurologicaldeficitXSkullFracturesimpleXcompoundXcomplex,open,lossofbraintissueXPDCEN/TR16148:2011CEN/TR16148:2011(E)Table1AISscalewithheadinjuryseverity6AIS0uninjuredAIS1minorAIS2slightAIS3moderateAIS4seriousAIS5severeAIS6unsurviveableWholeareaSkinsuperficialabrasions,contusions,lacerationsXmajorlacerationorminorbloodlossXbloodloss20%XDecapitationXVessels(arteries)carotid,jugularandvertebrallacerationminorXcarotidjugularandvertebrallacerationmajorXNervesvagusinjuryXphrenicinjuryXSpinehyoidfractureXcordcontusionXincompletecordsyndromeXcompletecordsyndromeorlacerationC-4orbelowXcompletecordsyndromeorlacerationC-3oraboveXdiscinjurywithoutnerverootdamageXdiscinjurywithnerverootdamageXPDCEN/TR16148:2011CEN/TR16148:2011(E)Table2AISscalewithneckinjuryseverity7AIS0uninjuredAIS1minorAIS2slightAIS3moderateAIS4seriousAIS5severeAIS6unsurviveable1stdegreeunspecifiedX2nddegree10%TBS(TotalBodySurface)X3rddegree10%TBSX10%TBSwithface,handorgenitaliainvolvementX2ndor3rddegree10%to19%TBSX10%to19%TBSwithface,handorgenitaliainvolvementX20%to29%TBSX20%to29%TBSwithface,handorgenitaliainvolvementX30%to39%TBSX30%to39%TBSwithface,handorgenitaliainvolvementX40%to89%TBSX90%XTBS=TotalBodySurfacePDCEN/TR16148:2011CEN/TR16148:2011(E)Table3AISscalewithburninjuryseverity8PeakAccelerationAIS300gAIS6PDCEN/TR16148:2011CEN/TR16148:2011(E)2Peaklinearacceleration(A.3.1&A.4)Thisisthemostfrequentlyusedparameterinhelmettestingandisderivedusuallyfromatri-axialaccelerometermountedintheheadformunlesstheheadformisrigidlysupportedandthenthesourceisasingleaxisaccelerometer.Inbothtypes,thehelmetismountedontotheheadformandthentheapparatusallowedtofallunimpededontoarigidanvil.Table4isascalepublishedbyNewman(1980)andissupportedbyresearchthatismorerecent.Table4PeakaccelerationandtypicalAISEquivalentAlthoughnotspecificallystatedintheoriginalresearchpaperitshouldbeconsideredthattheabovevaluesrepresent50thpercentile,whichmeansthat50percentofthepopulationwouldsustainaninjuryofagivenAISseverityforthecorrespondingrangeofacceleration.Itisinterestingtonotethathistorically,valueshavebeensetwhichcorrespondtoAIS5andthatthishasresultedinhelmetsthathavegivenreasonableprotection.Insomestandards,thehelmetismountedontoafixedheadformandthenamassisdroppedontothehelmet.ValuesgiveninTable4maybeusedwithcautionprovidedthefallingmassisapproximately5kgandtheheadformisattachedtoanappropriateneck.Replacingthefixedheadformtestbyafallingheadform,guidedorfree-fall,shouldbeconsidered.3HeadinjurycriterionHIC(A.4)HIC=aresdt(t2t1)AnnexAgivesdetailsofthederivationofHICandtheformulaisgivenbelow.1t22,5t2t1t1maxThebenefitofHICoverpeaklinearaccelerationisthatHICisrelatedtotimeanditisknownthatpulseswiththesamepeakvaluebutdifferentdurationcangiveadifferentinjuryoutcome.Unfortunately,HICandAISvalueshaveneverbeensatisfactorilycorrelated.Although,recentresearch(COST327)hasprovidedtentativevaluesforAIS2andAIS3,seebelow.Nevertheless,researchershaveprovidedanassessmentoftheprobabilityofdeathforHICranges.AsummaryofthevariousfindingsisgiveninTable5.9HICProbabilityofdeathAIS(whereknown)100010%-15%2150035%3200035%-50%300055%400060%-65%PeakrotationalaccelerationAISProbabilityofinjury5000rad/s21-210000rad/s23-635%PeaktangentialforceAISProbabilityofinjury1000N1-2000N2-3500N(Reg22-05)350%4000N350%7000N4-PDCEN/TR16148:2011CEN/TR16148:2011(E)Table5ProbabilityofdeathforHICrangesItshouldbenotedthatwherearangeisgiven,thisisindicativeofmorethanonesource.ItshouldalsobenotedthatHICisderivedfromtheGSI(GaddSeverityIndex)(seeA.4.2)usedinsomeStandards.GSIandHICarepotentiallyinterchangeablebutonlyforregularpulseshapes.Therefore,itisrecommendedthatGSIbereplacedbyHIC.44.1Rotationalmotion(A.2.6,A.3.2&A.4.3)PeakRotationalAccelerationresearchshows,Table6,thatconcussionAIS1-2canoccurat5000rad/secandfatalinjuryAIS5-6canpotentiallyoccurat10000rad/sec.Thiscorrelateswithd