ASTM_D_6468_-_22.pdf

Designation:D646822Standard Test Method forHigh Temperature Stability of Middle Distillate Fuels1This standard is issued under the fixed designation D6468;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This test method covers relative stability of middledistillate fuels under high temperature aging conditions withlimited air exposure.This test method is suitable for all No.1and No.2 grades in Specifications D396,D975,D2880,andD3699.It is also suitable for similar fuels meeting otherspecifications.1.2 This test method is not suitable for fuels whose flashpoint,as determined by Test Methods D56,D93,or D3828,isless than 38 C.This test method is not suitable for fuelscontaining residual oil.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.3.1 ExceptionThe maximum vacuum includes inch-pound units in 6.5 and 11.2.1.4 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2D56 Test Method for Flash Point by Tag Closed Cup TesterD93 Test Methods for Flash Point by Pensky-MartensClosed Cup TesterD396 Specification for Fuel OilsD975 Specification for Diesel FuelD1500 Test Method for ASTM Color of Petroleum Products(ASTM Color Scale)D2274 Test Method for Oxidation Stability of Distillate FuelOil(Accelerated Method)D2880 Specification for Gas Turbine Fuel OilsD3699 Specification for KerosineD3828 Test Methods for Flash Point by Small Scale ClosedCup TesterD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4175 Terminology Relating to Petroleum Products,LiquidFuels,and LubricantsD4625 Test Method for Middle Distillate Fuel StorageStability at 43 C(110 F)D5452 Test Method for Particulate Contamination in Avia-tion Fuels by Laboratory Filtration3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this test method,referto Terminology D4175.3.2 Definitions of Terms Specific to This Standard:3.2.1 adherent insolubles,nmaterial that is produced inthe course of stressing distillate fuel under the conditions ofthis test,and that adheres to the glassware after fuel has beenflushed from the system.3.2.2 filterable insolubles,nmaterial that is produced inthe course of stressing distillate fuel under the conditions ofthis test,and that is capable of being removed from the fuel byfiltration.3.2.3 inherent stability,nthe resistance to change whenexposed to air,in the absence of other environmental factorssuch as water,reactive metal surfaces,and dirt.3.2.4 storage stability,nthe resistance of fuel to formationof degradation products when stored at ambient temperatures.3.2.5 thermal stability,nthe resistance of fuel to formationof degradation products when thermally stressed.4.Summary of Test Method4.1 Two 50 mL volumes of filtered middle distillate fuel areaged for 90 min or 180 min at 150 C in open tubes with air1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products,Liquid Fuels,and Lubricants and is the direct responsibility ofSubcommittee D02.14 on Stability,Cleanliness and Compatibility of Liquid Fuels.Current edition approved May 1,2022.Published May 2022.Originallyapproved in 1999.Last previous edition approved in 2019 as D6468 08(2019).DOI:10.1520/D6468-22.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1exposure.After aging and cooling,the fuel samples are filteredand the average amount of filterable insolubles is estimated bymeasuring the light reflectance of the filter pads.The 100%and