Selecting Your Gear: Learning About Materials

NFPA-certified turnout gear consists of three layers of materials – together called a composite – which is made up of an outer shell, a moisture barrier, and a ... FindaDistributorHome / SelectingYourGear:LearningAboutMaterialsSelectingYourGear:LearningAboutMaterialsLearningAboutMaterialsGlobeinventedandpatentedtheoriginalthree-layermaterialsystemover100yearsago.Technology,design,andprotectionhaveobviouslychangeddramaticallysincethoseearlydays,buttheoriginalconceptofmakingturnoutgearfromthesethreelayersstillprovidesthefoundationofcurrentturnoutgear.Whatmaterialsgointomakingturnoutgear?NFPA-certifiedturnoutgearconsistsofthreelayersofmaterials–togethercalledacomposite–whichismadeupofanoutershell,amoisturebarrier,andathermalliner.Thisthree-layersystemwasoriginallyinventedandpatentedbythefounderofGlobeover100yearsago.Technology,design,andprotectionhaveobviouslychangeddramaticallysincethoseearlydays,buttheoriginalconceptofmakingturnoutgearfromthesethreelayersstillprovidesthefoundationofcurrentturnoutgear.Viewourselectionofturnoutgearfabrics.Whatisthefunctionoftheoutershell?Thepurposeoftheoutershellistoprotectthefirefighterfromdirectflamewhileprovidingabrasionandtearresistanceandsomethermalprotection.Outershellfabriccomesinavarietyoffiberblends,weaves,andweights,whichimpactsbreak-openresistance,strength,abrasionresistance,flexibility,anddurability.Whatisthefunctionofthemoisturebarrier?ThemoisturebarrierprotectsthefirefighterfromwaterandNFPA“commonliquids”(chlorine,batteryacids,aqueousfilmformingfoam,gasoline,hydraulicfluid,andantifreezefluid)andisalsotestedforresistancetobloodbornepathogens.Themoisturebarrierisrequiredtoprovide"breathability”–lettingperspirationmoveawayfromthewearer.Thislayerismadefromanengineeredmembranelaminatedtoawovenornon-wovensubstrate.Whatisthefunctionofthethermalliner?Thethermallinerprovidesmostofthethermalprotectionfromambientheat–themorethermalprotection,thelongeritwilltakeforthefirefightertofeeltheheat.Thermallinerstypicallyconsistofalightweightwovenfaceclothliningfacingyourbodyquiltedtooneormorelayersofinsulatingnon-wovenbatting.Thefaceclothismadefromavarietyoffibersinspun(likecotton)formorfilament(likefishingline)oracombinationofthetwo.Withmorefilamentfiber,theliningfabricslidesmoreeasilyagainstyourbody,whichmakesthegearmorecomfortableaswellasmakingiteasiertoslideinandoutofyourgear.Thebattingistypicallyaone-layerneedlepunch(likefelt)ortwoormorelayersofaspunlace(hydro-entangled)whichislighterandmoreflexible.Howarethermalperformanceandbreathabilitytested?Boththethermalprotectiveperformanceandthe“breathability”aretestedonthebasethree-layercompositethatmakesuptheturnoutgear.TheTPPtestwasintroducedinthe1986editionofNFPA1971,withaminimumperformanceratingof35,whichremainstherequiredtestvaluetoday.Inthistest,samplesofthethree-layercompositearesubjectedtoabankofquartzlampssimultaneouslywithdirectflameexposure,simulatingflashoverconditions.TheTPPvalueisdeterminedstrictlybythethreemateriallayersspecifiedandisnotimpactedbydesignorconstruction.Differentcombinationswillyielddifferentresultsand,roughlyspeaking,ifyoutaketheTPPvalueofanythree-layerensembleanddivideitinhalf,thiswouldbethenumberofsecondsofescapetimeforafirefightercaughtinthisenvironmentbeforehewouldreceiveaseconddegreeburn.Thesecondtest,totalheatloss(THL)isoftenreferredtoasthebreathabilitytest.TheTHLtestwasfirstintroducedinthe1997editionofNFPA1971asanannexitemandbecamearequirementinthe2000edition.Thistestisrunonaguardedsweatinghotplateandmeasurestheabilityofthesamethreebaselayerstoallowheattopassthroughthecomposite.Notsurprisingly,thesetwotestsarelikeaseesaw;intheTPPtestwearemeasuringtheabilityofthelayerstodeterheatfromtheoutsideenvironmententeringthroughthesystem,andintheTHLtestwearemeasuringtheabilityofthesesamethreelayerstodissipatebodyheatfromtheinsidetotheoutside.MaterialSelectionGuideExploreourselectionofoutershells,moisturebarriers,thermalliners,andmore.ViewtheguideNext:Evaluating,Specifying,&PurchasingSelectingYourGear1UnderstandingStandards2CreatingaRiskAssessment3SelectingaStyle,Features,&Options4LearningAboutMaterials5Evaluating,Specifying,&PurchasingContactyourGlobedistributorTurnoutGearBootsFindaDistributorFindADistributorAccessMSA'snetworkofGlobedistributors.StayInformedStayInformedSignuptogetthelatestindustryresources,productinformation,monthlynewsletter,andrelatedtopics.SignUpFOLLOWUS: