1、Designation: D891 18Standard Test Methods forSpecific Gravity, Apparent, of Liquid Industrial Chemicals1This standard is issued under the fixed designation D891; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revi
2、sion. 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 These test methods cover the determinati
3、on of thespecific gravity, apparent, of liquid industrial chemicals. Twotest methods are covered as follows:1.1.1 Test Method A, specific gravity, apparent, by means ofa hydrometer.1.1.2 Test Method B, specific gravity, apparent, by means ofa pycnometer.NOTE 1Test Method D4052 describes an instrumen
4、tal procedure.1.2 In common usage the term specific gravity, apparent, isunderstood to mean specific gravity.1.3 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thesetest methods with the exception of Fahrenheit (F) in 5.1 as anexample of a
5、possible industrial specification unit.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
6、 of regulatory limitations prior to use.For specific hazard statements, see Sections 8 and 16.1.5 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 Stan
7、dards, Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2D1193 Specification for Reagent WaterD4052 Test Method for Density, Relative Density, and APIGravity of Liquids by Digital Density MeterD680
8、9 Guide for Quality Control and Quality AssuranceProcedures for Aromatic Hydrocarbons and Related Ma-terialsE1 Specification for ASTM Liquid-in-Glass ThermometersE100 Specification for ASTM HydrometersE202 Test Methods for Analysis of Ethylene Glycols andPropylene GlycolsE302 Test Methods for Monoba
9、sic Organic Acids (With-drawn 2001)3E346 Test Methods for Analysis of Methanol (Withdrawn2017)32.2 Other Document:4OSHA Regulations, 29 CFR paragraphs 1910.1000 and1910.12003. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 specific gravity, apparentthe ratio of the weight inair
10、of a unit volume of a material at a stated temperature to theweight in air of equal density of an equal volume of gas-freedistilled water (see Note 2) at a stated temperature. It shall bestated as follows:Specific gravity, apparent, x/yoC (1)where x is the temperature of the material and y is thetem
11、perature of the water.NOTE 2Gas-free distilled water is distilled water that has been boiledto eliminate dissolved gases.4. Significance and Use4.1 Specific gravity, apparent, may be used as a qualitativetest in establishing the identity of a chemical. It may be used tocalculate the volume occupied
12、by a product whose weight isknown, or to calculate the weight of a product from its volume.It may be used to determine the composition of binary mixtures1These test methods are under the jurisdiction of ASTM Committee D16 onAromatic, Industrial, Specialty and Related Chemicals and are the direct res
13、ponsi-bility of Subcommittee D16.15 on Industrial and Specialty General Standards.Current edition approved Aug. 1, 2018. Published August 2018. Originallyapproved in 1946. Last previous edition approved in 2009 as D891 09 which waswithdrawn January 2018 and reinstated in August 2018. DOI: 10.1520/D0
14、891-18.2For 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.3The last approved version of this historical standard
15、 is referenced onwww.astm.org.4Available from U.S. Government Printing Office, Superintendent ofDocuments, 732 N. Capitol St., NW, Washington, DC 20401-0001, http:/www.access.gpo.gov.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive,
16、 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 issue
17、d by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1of pure chemicals. In the case of most refined industrialchemicals specific gravity, apparent, is of minimal value indefining quality, although it may detect gross contamination.4.2 Of the two test methods described, the
18、pycnometermethod (Test Method B, 1.1.2) is the most accurate andprecise. For this reason it is the preferred method in case ofdisputes. The hydrometer method (Test MethodA, 1.1.1)istheleast accurate and precise, but it is also the simplest and fastestto perform and is often entirely satisfactory for
19、 many purposes.If the sample is too viscous to permit the hydrometer to floatfreely, the pycnometer test method should be used.5. Test Temperatures5.1 Specifications for industrial chemicals often specifydifferent temperatures at which specific gravity, apparent, shallbe measured, for example:Specif
20、ic gravity, apparent, at 15.56/15.56C,Specific gravity, apparent, at 20/20C,Specific gravity, apparent, at 25/25C, orSpecific gravity, apparent, at 60/60F.Where precision is desired, it is necessary to determine thespecific gravity, apparent, at the temperature prescribed in thespecifications for th
21、e material to be tested and to use instru-ments that have been calibrated and standardized at thespecified temperature.5.2 The expression “specific gravity, apparent, at 25.0/15.56C,” for example, means the ratio of the weight in air ofa unit volume of a material at 25.0C to the weight in air ofequa
22、l density of an equal volume of gas-free distilled water at15.56C.5.3 It is possible to convert the specific gravity, apparent, atx/T1C to the corresponding value at x/T2C by multiplying thevalue at T1by the factor given in Table 1. For example, a liquidhas a specific gravity, apparent, of 0.9500 at
23、 20/20C and thevalue at 20/4C is desired: 0.9500 0.9982336 = 0.9483, thevalue at 20/4C. The values in Table 1 are the ratios of thedensity of water at the appropriate temperatures.5.4 If the change in specific gravity, apparent, with tempera-ture of the liquid is known, the specific gravity, apparen
24、t, atT1/y may be converted to that at T2/y by the following equation:Specific gravity, apparent, at T2/y 5 T12 T2!k1specific gravity, apparent, at T1/y(2)where:T1= original temperature, C,T2= the second temperature, C, andk = change in specific gravity, apparent, per C.Example: The specific gravity,
25、 apparent, of n-butanol at20/20C is 0.8108 and the change in specific gravity, apparent,is 0.00074/C. What is the specific gravity, apparent, at4/20C?Specific gravity, apparent, at 4/20C 5 20 2 4!0.00074#10.81085 0.8226 (3)TEST METHOD ASPECIFIC GRAVITY,APPARENT, BY MEANS OF A HYDROMETER6. Summary of
26、 Test Method6.1 The specific gravity, apparent, of the sample is deter-mined by immersing a calibrated hydrometer in the sample atthe test temperature. The displacement of the hydrometer is afunction of the specific gravity, apparent, of the sample that isread on the hydrometer scale at the level of
27、 the meniscus of thesample.7. Apparatus7.1 HydrometerThe hydrometers to be used shall be thosespecified in Specification E100, as follows:Nominal Apparent SpecificGravity RangeASTMHydrometer No.0.650 to 0.700 82H-620.700 to 0.750 83H-620.750 to 0.800 84H-620.800 to 0.850 85H-620.850 to 0.900 86H-620
28、.900 to 0.950 87H-620.950 to 1.000 88H-621.000 to 1.050 89H-621.050 to 1.100 90H-621.100 to 1.150 113H-621.150 to 1.200 114H-621.200 to 1.250 115H-62NOTE 3TheASTM hydrometers prescribed in Test MethodA, 7.1, arecalibrated as if all weights are in vacuum. Equivalent values at the sametemperature for
29、all weights in air may be approximated for ambientconditions as follows:apparent specific gravity 5 1.00120 3 sp gr! 2 0.00120where:sp gr = specific gravity determined by ASTM hydrometer.7.2 Hydrometer CylinderThe vessel in which the samplefor the gravity test is confirmed shall be made of clear gla
30、ss andshall be cylindrical in shape. For convenience in pouring, itmay have a lip on the rim. The inside diameter shall be at least25 mm greater than the outside diameter of the hydrometerused in it. The height of the cylinder shall be such that afterequilibrium has been reached, the lowest point on
31、 the hydrom-eter will be at least 25 mm off the bottom of the cylinder.7.3 ThermometerThe thermometers used shall be thosespecified in Specification E1. Thermometer 90C, a 76-mmTABLE 1 Conversion of Specific Gravities, Apparent, from Basis x/T1to Basis x/ T2CSpecific Gravities,Apparent, on Basis x/T
32、1Multiplied by This Factor Gives Specific Gravities, Apparent, on Basis x/T2t/4 t/15 t/15.56 t/20 t/25t/4 1 1.0008722 1.0009586 1.0017695 1.0029335t/15 0.9991286 1 1.0000864 1.0008966 1.0020595t/15.56 0.9990423 0.9999136 1 1.0008101 1.0019730t/20 0.9982336 0.9991042 0.9991905 1 1.0011619t/25 0.99707
33、51 0.9979447 0.9980309 0.9988395 1D891 182immersion thermometer, covering 0 to 30C with 0.1Cgraduations, is recommended for most work. Thermometer63C is similar except it is a total immersion type and covers 8to 30C with 0.1C graduations.7.4 Water BathA water bath capable of maintaining theselected
34、test temperature 60.05C. The depth of the bath mustbe sufficient to immerse the hydrometer cylinder so that thecontained liquid is completely below the surface of the liquidin the bath.8. Hazards8.1 Consult current OSHA regulations,4suppliers SafetyData Sheets, and local regulations for all material
35、s used in thistest method.9. Procedure9.1 Cool the sample in the original container to about 2Cbelow the temperature at which the specific gravity, apparent,is to be determined. Rinse each piece of equipment with aportion of the sample and discard the rinse liquid. Pour thesample into the clean hydr
36、ometer cylinder without splashing,so as to avoid formation of air bubbles. Remove any airbubbles adhering to the surface by touching them with a pieceof clean filter paper. Select a location that is free from aircurrents. Place the cylinder vertically in the waterbath and letthe temperature of the s
37、ample reach the temperature of the bath60.05C as follows: Stir the contents of the cylinder, beingcareful to avoid formation of air bubbles. When the tempera-ture of the sample is about 0.2C below that of the bath, slowlyand carefully lower the hydrometer into the sample to a leveltwo smallest scale
38、 divisions below that at which it will floatand then release the hydrometer. After it has come to rest andfloats freely away from the walls of the cylinder, read thegravity as the point at which the surface of the sampleapparently cuts the hydrometer scale. When the temperature ofthe sample matches
39、that of the bath, make this observation byplacing the eye slightly below the level of the liquid and slowlyraise the eye until the surface of the sample first seen as adistorted ellipse seems to become a straight line cutting thehydrometer scale. Determine the temperature of the sample justbefore an
40、d also, for referee tests, just after reading thehydrometer.9.2 Repeat 9.1 and average the results.10. Report10.1 Report the reading obtained in 9.1 plus any calibrationcorrection as the specific gravity, apparent, of the sample to thenearest 0.0001 unit.11. Precision and Bias11.1 Precision:11.1.1 T
41、he precision of this test method should be deter-mined for each chemical to provide criteria for judging theacceptability of results. The following precision data reportedin Test Method E302 for monobasic organic acids are typical.11.1.2 Repeatability (Single Analyst)The standard devia-tion for a si
42、ngle determination has been estimated to be0.00020 unit at 24 DF. The 95 % limit for the differencebetween two such runs is 0.0005 unit.11.1.3 Within-Laboratory, Between-Days VariabilityThestandard deviation of results (each the average of duplicates),obtained by the same analyst on different days,
43、has beenestimated to be 0.00016 unit at 12 DF. The 95 % limits for thedifference between two such averages is 0.005 unit.11.1.4 Reproducibility (Multilaboratory)The standard de-viation of results (each the average of duplicates), obtained byanalysts in different laboratories, has been estimated to b
44、e0.00057 unit at 5 DF. The 95 % limit for the difference betweentwo such averages is 0.0015 unit.11.2 BiasThe bias of this test method has not beendetermined due to the unavailability of suitable referencematerials. However, the bias is dependent upon the calibrationof the hydrometer and the degree
45、of control of the temperatureof the hydrometer bath.12. Quality Guidelines12.1 Laboratories shall have a quality control system inplace.12.1.1 Confirm the performance of the test instrument ortest method by analyzing a quality control sample followingthe guidelines of standard statistical quality co
46、ntrol practices.12.1.2 A quality control sample is a stable material isolatedfrom the production process and representative of the samplebeing analyzed,12.1.3 When QA/QC protocols are already established inthe testing facility, these protocols are acceptable when theyconfirm the validity of test res
47、ults.12.1.4 When there are no QA/QC protocols established inthe testing facility, use the guidelines described in GuideD6809 or similar statistical quality control practices.TEST METHOD BSPECIFIC GRAVITY, APPARENT,BY MEANS OF A PYCNOMETER513. Summary of Test Method13.1 A tared pycnometer is filled w
48、ith freshly boiled waterthat has been cooled to the specified test temperature andweighed to determine the weight of water in the filledpycnometer. The same pycnometer is filled with the sample atthe test temperature and weighed. The ratio of the weight ofsample to water in air is the specific gravi
49、ty, apparent.14. Apparatus14.1 PycnometerA pycnometer of 25-mL capacity with aground-glass stopper having a capillary opening, a chamber toprovide for expansion up to room temperature, and a cap toprevent evaporation.14.2 Water BathA water bath capable of maintaining thetest temperature at 60.05C during the test.5For a high degree of accuracy, the following paper discusses an apparatus andmethod of much merit: Lipkin and Associates, “Pycnometer for Volatile Liquids,”Industrial and Engineering Chemistry,Analytical Edition, Vol 3
