Designation: D4052 − 18Standard Test Method forDensity, Relative Density, and API Gravity of Liquids byDigital Density Meter1This standard is issued under the fixed designation D4052; 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.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope*1.1 This test method covers the determination of the density,relative density, and API Gravity of petroleum distillates andviscous oils that can be handled in a normal fashion as liquidsat the temperature of test, utilizing either manual or automatedsample injection equipment. Its application is restricted toliquids with total vapor pressures (see Test Method D5191)typically below 100 kPa and viscosities (see Test Method D445or D7042) typically below about 15 000 mm2/s at the tempera-ture of test. The total vapor pressure limitation however can beextended to 100 kPa provided that it is first ascertained thatno bubbles form in the U-shaped, oscillating tube, which canaffect the density determination. Some examples of productsthat may be tested by this procedure include: gasoline andgasoline-oxygenate blends, diesel, jet, basestocks, waxes, andlubricating oils.1.1.1 Waxes and highly viscous samples were not includedin the 1999 interlaboratory study (ILS) sample set that wasused to determine the current precision statements of themethod, since all samples evaluated at the time were analyzedat a test temperature of 15 °C. Wax and highly viscous samplesrequire a temperature cell operated at elevated temperaturesnecessary to ensure a liquid test specimen is introduced foranalysis. Consult instrument manufacturer instructions forappropriate guidance and precautions when attempting toanalyze wax or highly viscous samples. Refer to the Precisionand Bias section of the method and Note 9 for more detailedinformation about the 1999 ILS that was conducted.1.2 In cases of dispute, the referee method is the one wheresamples are introduced manually as in 6.3 or 6.4, as appropri-ate for sample type.1.3 When testing opaque samples, and when not usingequipment that is capable of automatic bubble detection,proper procedure shall be established so that the absence of airbubbles in the sample cell can be established with certainty.For the determination of density in crude oil samples use TestMethod D5002.1.4 The values stated in SI units are regarded as thestandard, unless stated otherwise. The accepted units of mea-sure for density are grams per millilitre (g/mL) or kilogramsper cubic metre (kg/m3).1.5 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.For specific warning statements, see 7.4, 7.5, and 10.3.1.6 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:2D287 Test Method for API Gravity of Crude Petroleum andPetroleum Products (Hydrometer Method)D445 Test Method for Kinematic Viscosity of Transparentand Opaque Liquids (and Calculation of Dynamic Viscos-ity)D1193 Specification for Reagent WaterD1250 Guide for Use of the Petroleum Measurement TablesD1298 Test Method for Density, Relative Density, or APIGravity of Crude Petroleum and Liquid Petroleum Prod-ucts by Hydrometer MethodD4057 Practice for Manual Sampling of Petroleum andPetroleum ProductsD4177 Practice for Automatic Sampling of Petroleum andPetroleum Products1This test method is under the jurisdiction of ASTM Committee D02 onPetroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility ofSubcommittee D02.04.0D on Physical and Chemical Methods.Current edition approved May 1, 2018. Published May 2018. Originallyapproved in 1981. Last previous edition approved in 2016 as D4052 – 16. DOI:10.1520/D4052-18.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at
[email protected] For Annual Book of ASTMStandards volume information, refer to the standard’s 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.1D4377 Test Method for Water in Crude Oils by Potentiomet-ric Karl Fischer TitrationD5002 Test Method for Density and Relative Density ofCrude Oils by Digital Density AnalyzerD5191 Test Method for Vapor Pressure of Petroleum Prod-ucts (Mini Method)D7042 Test Method for Dynamic Viscosity and Density ofLiquids by Stabinger Viscometer (and the Calculation ofKinematic Viscosity)3. Terminology3.1 Definitions:3.1.1 density, n—mass per unit volume at a specified tem-perature.3.1.2 relative density, n—the ratio of the density of amaterial at a stated temperature to the density of water at astated temperature.3.2 Definitions of Terms Specific to This Standard:3.2.1 adjustment, v—the operation of bringing the instru-ment to a state of performance suitable for its use, by setting oradjusting the density meter constants.3.2.1.1 Discussion—On some digital density analyzerinstruments, an adjustment may be made rather than calibratingthe instrument. The adjustment procedure uses air and freshlyboiled reagent water (Warning—Handling water at boiling ornear boiling temperature can present a safety hazard. Wearappropriate personal protective equipment.) as standards toestablish the linearity of measurements over a range ofoperating temperatures.3.2.2 calibration, v—set of operations that establishes therelationship between the reference density of standards and thecorresponding density reading of the instrument.4. Summary of Test Method4.1 A small volume, approximately 1 mL to 2 mL, of liquidsample is introduced into an oscillating sample tube and thechange in oscillating frequency caused by the change in themass of the tube is used in conjunction with calibration data todetermine the density, relative density, or API Gravity of thesample. Both manual and automated injection techniques aredescribed.5. Significance and Use5.1 Density is a fundamental physical property that can beused in conjunction with other properties to characterize boththe light and heavy fractions of petroleum and petroleumproducts.5.2 Determination of the density or relative density ofpetroleum and its products is necessary for the conversion ofmeasured volumes to volumes at the standard temperature of15 °C.6. Apparatus6.1 Digital Density Analyzer—A digital analyzer consistingof a U-shaped, oscillating sample tube and a system forelectronic excitation, frequency counting, and display. Theanalyzer shall accommodate the accurate measurement of thesample temperature during measurement or shall control thesample temperature as described in 6.2.The instrument shall becapable of meeting the precision requirements described in thistest method.6.2 Circulating Constant-Temperature Bath, (optional), ca-pable of maintaining the temperature of the circulating liquidconstant to 60.05 °C in the desired range. Temperature controlcan be maintained as part of the density analyzer instrumentpackage.6.3 Syringes, for use primarily in manual injections, at least2 mL in volume with a tip or an adapter tip that will fit theopening of the oscillating tube.6.4 Flow-Through or Pressure Adapter, for use as an alter-native means of introducing the sample into the densityanalyzer either by a pump, by pressure, or by vacuum.NOTE 1—It is highly recommended that a vacuum not be applied tosamples prone to light-end loss, as it can easily lead to the formation ofbubbles. It is recommended to fabricate a special cap or stopper for samplecontainers so that air, such as from a squeeze pump, is used to displace atest specimen to the U-tube measuring cell by the flow-through method.6.5 Autosampler, required for use in automated injectionanalyses. The autosampler shall be designed to ensure theintegrity of the test specimen prior to and during the analysisand be equipped to transfer a representative portion of testspecimen to the digital density analyzer.6.6 Temperature Sensing Device (TSD), capable of monitor-ing the observed test temperature to within an accuracy of6 0.05 °C. If a liquid-in-glass thermometer is used as the TSD,it shall be calibrated and graduated to 0.1 °C, and have a holderthat can be attached to the instrument for setting and observingthe test temperature. In calibrating the thermometer, the icepoint and bore connections should be estimated to the nearest0.05 °C. For non-mercurial thermometers, the TSD deviceshall be calibrated at least annually against a certified andtraceable standard.6.7 Ultrasonic Bath, Unheated, (optional), of suitable di-mensions to hold container(s) placed inside of bath, for use ineffectively dissipating and removing air or gas bubbles thatmay be entrained in viscous sample types prior to analysis.7. Reagents and Materials7.1 Purity of Reagents—Reagent grade chemicals shall beused in all tests. Unless otherwise indicated, it is intended thatall reagents shall conform to the specifications of the Commit-tee on Analytical Reagents of the American Chemical Society,where such specifications are available.3Other grades may beused, provided it is first ascertained that the reagent is ofsufficiently high purity to permit its use without lessening theaccuracy of the determination.3Reagent Chemicals, American Chemical Society Specifications, AmericanChemical Society, Washington, DC. For suggestions on the testing of reagents notlisted by the American Chemical Society, see Analar Standards for LaboratoryChemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeiaand National Formulary, U.S. Pharmaceutical Convention, Inc. (USPC), Rockville,MD.D4052 − 1827.2 Purity of Water—Unless otherwise indicated, referencesto water shall be understood to mean reagent water as definedby Type II of Specification D1193 or higher.7.3 Water, reagent water, freshly boiled to remove dissolvedgasses, for use as primary calibration standard. (Warning—Handling water at boiling or near boiling temperature canpresent a safety hazard. Wear appropriate personal protectiveequipment.)7.4 Cleaning Solvent, such as petroleum naphtha4(Warning—Petroleum naphtha is extremely flammable), orother materials that are capable of flushing and removingsamples entirely from the sample tube.7.5 Acetone, for flushing and drying the sample tube.(Warning—Extremely flammable.)7.6 Dry Air, for drying the oscillator tube.8. Sampling, Test Specimens, and Test Units8.1 Sampling is defined as all the steps required to obtain analiquot of the contents of any pipe, tank, or other system, andto place the sample into the laboratory test container. Thelaboratory test container and sample volume shall be ofsufficient capacity to mix the sample and obtain a homoge-neous sample for analysis.8.2 Laboratory Sample—Use only representative samplesobtained as specified in Practices D4057 or D4177 for this testmethod.8.3 Test Specimen—Aportion or volume of sample obtainedfrom the laboratory sample and delivered to the densityanalyzer sample tube. The test specimen is obtained as follows:8.3.1 Mix the sample if required to homogenize, taking careto avoid the introduction of air bubbles. The mixing may beaccomplished as described in Practice D4177 or Test MethodD4377. Mixing at room temperature in an open container canresult in the loss of volatile material from certain sample types(for example, gasoline samples), so mixing in closed, pressur-ized containers or at least 10 °C below ambient temperature isrequired for such sample types where loss of volatile materialis a potential concern. For some sample types, such as viscouslube oils that are prone to having entrained air or gas bubblespresent in the sample, the use of an ultrasonic bath (see 6.7)without the heater turned on (if so equipped), has been foundeffective in dissipating bubbles typically within 10 min.NOTE 2—When mixing samples with volatile components, consider thesample properties in relation to both ambient temperature and pressure.8.3.2 For manual injections, draw the test specimen from aproperly mixed laboratory sample using an appropriate sy-ringe. If the proper density analyzer attachments and connect-ing tubes are used, as described in 6.4, then the test specimencan be delivered directly to the analyzer’s sample tube from themixing container. For automated injections, it is necessary tofirst transfer a portion of sample by appropriate means from aproperly mixed laboratory sample to the autosampler vials, andtake the necessary steps to ensure the integrity of the testspecimen prior to and during the analysis. Sample vials for theautosampler shall be sealed immediately after filling up to80 % 6 5 % and shall be kept closed until the auto samplertransfers the test specimen into the measuring cell. For highlyvolatile samples, cool the sample prior to measurement. Followthe manufacturer’s instructions.NOTE 3—Overfilled sample vials can result in cross-contaminationbetween sample vials.9. Preparation of Apparatus9.1 Set up the density analyzer (including the constanttemperature bath and related attachments, if necessary) follow-ing the manufacturer’s instructions. Adjust the bath or internaltemperature control so that the desired test temperature isestablished and maintained in the sample compartment of theanalyzer. Calibrate the instrument at the same temperature atwhich the density or relative density of the sample is to bemeasured or perform an adjustment (see 3.2.1–Discussion) inpreparation of analyzing samples. (Warning—Precise settingand control of the test temperature in the sample tube isextremely important. An error of 0.1 °C can result in a changein density of one in the fourth decimal when measuring in unitsof grams per millilitre.)10. Calibration of Apparatus10.1 As a minimum requirement, calibration of the instru-ment is required when first set up, whenever the test tempera-ture is changed (unless the instrument is capable of performingan
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