Designation:C912−93(Reapproved2013)StandardPracticeforDesigningaProcessforCleaningTechnicalGlasses1ThisstandardisissuedunderthefixeddesignationC912;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversinformationthatwillpermitdesignofarationalcleaningprocedurethatcanbeusedwithaglassthatissomewhatsolubleinmanyaqueouschemicalsolutions.Typically,thistypeofglassisusedinapplicationssuchasopticalware,glass-to-metalseals,lowdielectriclossproducts,glassfibers,infraredtransmittingproducts,andproductsresis-tanttometallicvapors.1.2Inmostcases,thistypeofglasscontainshighconcen-trationsofoxidesthattendtoreactwithanumberofaqueouschemicals.SuchoxidesincludeB2O3,Al2O3,R2O,RO,La2O3,ZnO,PbO,P2O5,andFe2O3.Themoreconventionalhigh-silicaglassesareusuallymorechemicallyresistant,butthecleaningprinciplesoutlinedherealsoapplytothem.1.3Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.SpecifichazardstatementsaregiveninSection4andTable1.2.Terminology2.1DefinitionsofTermsSpecifictoThisStandard:2.1.1technicalglass—glassesdesignedwithsomespecificpropertyessentialforamechanical,industrial,orscientificdevice.3.SignificanceandUse3.1Manyofthelow-silicatechnicalglasseswhichcontainsolubleorreactiveoxidesrequireprocessingorinvolveappli-cationsthatrequirecleaning.Veryoftenthesecleaningproce-dureshaveevolvedoverseveraldecadesandareconsideredanart.Theyusuallycontainnumeroussteps,someofquestionablevalidity.Itisthepremiseofthispracticethatcleaningglasscanbemorescientific.Designofacleaningprocedureshouldinvolve(1)adefinitionofthesoiltoberemoved,(2)anawarenessoftheconstraintsimposedbytheglas...
