Designation:D4525−13´2StandardTestMethodforPermeabilityofRocksbyFlowingAir1ThisstandardisissuedunderthefixeddesignationD4525;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ε1NOTE—EditorialcorrectionsweremadethroughoutinFebruary2014.ε2NOTE—EditoriallyupdatedunitsofmeasurementstatementinApril2018.1.Scope*1.1Thistestmethodcoversthedeterminationofthecoef-ficientofspecificpermeabilityfortheflowofairthroughrocks.Themethodestablishesrepresentativevaluesofthecoefficientofpermeabilityofrocksorwell-induratedsoils.1.2Thistestmethodislimitedtopermeabilityvaluesgreaterthan9.869×10-18m2(0.01millidarcy),andislimitedtorocksfreeofoilorunctuousmatter.1.3ThevaluesstatedinSIunitsaretoberegardedasstandard.ThevaluesgiveninparenthesesafterSIunitsareprovidedforinformationonlyandarenotconsideredstandard.ReportingoftestresultsinunitsotherthanSIshallnotberegardedasnonconformancewiththistestmethod.1.4AllobservedandcalculatedvaluesshallconformtotheguidelinesforsignificantdigitsandroundingestablishedinPracticeD6026.1.4.1Theproceduresusedtospecifyhowdataarecollected/recordedorcalculated,inthisstandardareregardedastheindustrystandard.Inaddition,theyarerepresentativeofthesignificantdigitsthatgenerallyshouldberetained.Theproce-duresuseddonotconsidermaterialvariation,purposeforobtainingthedata,specialpurposestudies,oranyconsider-ationsfortheuser’sobjectives;anditiscommonpracticetoincreaseorreducesignificantdigitsofreporteddatatobecommensuratewiththeseconsiderations.Itisbeyondthescopeofthisstandardtoconsidersignificantdigitsusedinanalyticalmethodsforengineeringdesign.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafety,health,andenvironmentalpracticesanddeter-minetheapplicabili...
