1、Designation: D5188 14D5188 16Standard Test Method forVapor-Liquid Ratio Temperature Determination of Fuels(Evacuated Chamber and Piston Based Method)1This standard is issued under the fixed designation D5188; the number immediately following the designation indicates the year oforiginal adoption or,
2、 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 the determination of the temperature at which the vapor
3、 formed from a selected volume of volatilepetroleum product saturated with air at 0 C to 1 C (32 F to 34 F) produces a pressure of 101.3 kPa 101.3 kPa (one atmosphere)against vacuum.This test method is applicable to samples for which the determined temperature is between 36 C and 80 C (97 Fand 176 F
4、) and the vapor-liquid ratio is between 8 to 1 and 75 to 1.NOTE 1When the vapor-liquid ratio is 20:1, the result is intended to be comparable to the results determined by Test Method D2533.NOTE 2This test method may also be applicable at pressures other than one atmosphere, but the stated precision
5、may not apply.1.2 This test method is applicable to both gasoline and gasoline-oxygenate blends.1.2.1 Some gasoline-oxygenate blends may show a haze when cooled to 0 C to 1 C. If a haze is observed in 12.5, it shall beindicated in the reporting of results. The precision and bias statements for hazy
6、samples have not been determined (see Note 1012).1.3 The values stated in SI units are to be regarded as standard. The values given in parentheses are provided for informationonly.1.3.1 ExceptionThe values given in parentheses are provided for information only.1.4 This standard does not purport to a
7、ddress all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. For specific warnings, see Section 7.27 and subsection
8、8.1.1.2. Referenced Documents2.1 ASTM Standards:2D2533 Test Method for Vapor-Liquid Ratio of Spark-Ignition Engine Fuels (Withdrawn 2008)3D2892 Test Method for Distillation of Crude Petroleum (15-Theoretical Plate Column)D4057 Practice for Manual Sampling of Petroleum and Petroleum ProductsD6299 Pra
9、ctice for Applying Statistical Quality Assurance and Control Charting Techniques to Evaluate Analytical Measure-ment System PerformanceD6708 Practice for Statistical Assessment and Improvement of Expected Agreement Between Two Test Methods that Purportto Measure the Same Property of a Material3. Ter
10、minology3.1 Definitions of Terms Specific to This Standard:3.1.1 T(V/L = 20), nthe equilibrium temperature at which the partial pressure of a sample under test conditions is equal to 101.3kPa (14.69 psia) and the vapor-liquid ratio is 20.3.1.2 vapor-liquid ratio of a fuel, nthe ratio at a specified
11、temperature and pressure of the volume of vapor in equilibrium withliquid to the volume of sample charged, as a liquid, at 0 C (32 F).1 This test method is under the jurisdiction ofASTM Committee D02 on Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Subcommittee
12、D02.08 on Volatility.Current edition approved Jan. 1, 2014April 1, 2016. Published March 2014April 2016. Originally approved in 1991. Last previous edition approved in 20132014 asD5188D5188 14.13. DOI: 10.1520/D5188-14.10.1520/D5188-16.2 For referencedASTM standards, visit theASTM website, www.astm.
13、org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard a
14、nd is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only
15、 the current versionof the standard as published by ASTM is to be considered the official document.*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 States14. Summary of Test Met
16、hod4.1 A known volume of chilled, air-saturated sample is introduced into an evacuated, thermostatically controlled test chamberof known volume or a test chamber with moveable piston that expands the volume after sample introduction, the internal volumeof which is V/L+1 times of that of the total te
17、st specimen introduced into the chamber. The sample volume is calculated to givethe desired vapor-liquid ratio for the chamber volume in use. After injection, the chamber temperature is adjusted until a stablechamber pressure of 101.3 kPa (14.69 psia) is achieved.5. Significance and Use5.1 The tende
18、ncy of a fuel to vaporize in automotive engine fuel systems is indicated by the vapor-liquid ratio of the fuel.5.2 Automotive fuel specifications generally include T(V/L = 20) limits to ensure products of suitable volatility performance. Forhigh ambient temperatures, a fuel with a high value of T(V/
19、L = 20), indicating a fuel with a low tendency to vaporize, is generallyspecified; conversely for low ambient temperatures, a fuel with a low value of T(V/L = 20) is specified.6. Apparatus6.1 Apparatus suitable for use shall employ a small volume test chamber incorporating a transducer for pressure
20、measurementsand associated equipment for thermostatically controlling the chamber temperature, evacuating the test chamber prior to sampleintroduction, or expanding the volume after sample introduction by a moveable piston, and cleaning and purging the chamberfollowing the test. Critical elements of
21、 the apparatus shall meet the following specifications:6.1.1 Test Chamber, constructed of stainless steel or aluminum, designed to contain between 5 mL and 50 mL of liquid plusvapor with a tolerance of 61 % of the nominal capacity.NOTE 3The test chamber volumes of the instruments used for the 1991 c
22、ooperative test program to determine the precision and bias statements werebetween 5 mL and 15 mL of liquid plus vapor with a tolerance of 61 % of the nominal capacity.6.1.2 Pressure Transducer, minimum operational range from 1 kPa to 177 kPa (0 psia to 25.6 psia) with minimum resolutionof 0.1 kPa (
23、0.01 psi) and minimum accuracy of 60.8 kPa (60.12 psi). The pressure measurement system shall include associatedelectronics and readout devices to display the resulting pressure reading.6.1.3 Heater, thermostatically controlled heater capable of maintaining the test chamber within 0.1 C of the set t
24、emperature fora minimum of 5 minutes.NOTE 4The use of automated instruments that automatically adjust the temperature, after sample injection, to give a pressure of 101.3 kPa (14.69psia) is allowed.6.1.4 Platinum Resistance Thermometer, used to measure the temperature of the test chamber, having a m
25、inimum temperaturerange of 36 C to 80 C, minimum resolution of 0.1 C (0.2 F) and minimum accuracy of 60.1 C (60.2 F).6.2 Vacuum Pump, (when required to produce the vacuum), capable of reducing the pressure in the test chamber to less than0.01 kPa (0.001 psia).6.3 Syringes, (if required for sample in
26、troduction), gas-tight, 1 mL to 20 mL capacity with minimum accuracy and precision of61 %.6.4 Bath, iced water or air, for chilling the samples and syringe (if required) to between 0 C and 1 C (32 F to 34 F).6.5 Pressure Measuring Device, capable of measuring local station pressure with an accuracy
27、of 0.20 kPa (0.03 psi) or better,at the same elevation relative to sea level as the apparatus in the laboratory.6.5.1 When a mercury manometer is not used as the pressure measuring device, the calibration of the pressure measuring deviceemployed shall be periodically checked (with traceability to a
28、nationally recognized standard) to ensure that the device remainswithin the required accuracy specified in 6.5.6.6 McLeod Vacuum Gage or Calibrated Electronic Vacuum Measuring Device for Calibration, to cover at least the range from0.01 kPa to 0.67 kPa (0.1 mm Hg to 5 mm Hg). The calibration of the
29、electronic vacuum measuring device shall be regularlyverified in accordance with the annex section on Vacuum Sensors (A6.3) of Test Method D2892.7. Reagents and Materials7.1 Purity of ReagentsUnless otherwise indicated, all reagents shall conform to the specifications of the Committee onAnalytical R
30、eagents of the American Chemical Society4 where such specifications are available. Lower purities can be used,provided it is first ascertained that the reagent is of sufficient purity to permit its use without lessening the accuracy of thedetermination. Reagents used for performance checks (see 10.3
31、) shall be of at least 99 % purity.4 Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washington, DC. For Suggestions on the testing of reagents not listed bythe American Chemical Society, see Annual Standards for Laboratory Chemicals, BDH Ltd., Poole, Dorset,
32、U.K., and the United States Pharmacopeia and NationalFormulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville, MD.D5188 1627.2 Propan-2-ol, Anhydrous, (less than 0.1 % H2O). (WarningFlammable.)NOTE 5It has been reported that, if not originally inhibited against it, propan-2-ol can contain pe
33、roxides. When this occurs, an explosion is possiblewhen the storage of the vessel or other equipment such as a dispensing bottle, is near empty and approaching dryness.7.3 Toluene, (WarningToluene is flammable and a health hazard.)7.4 n -pentane, (WarningFlammable, health hazard.)8. Sampling8.1 Gene
34、ral:8.1.1 Conduct bulk sampling to obtain the laboratory samples in accordance with Practice D4057 except for gasoline-oxygenateblends where water displacement is not used. The extreme sensitivity of T(V/L) measurements to losses through evaporation andthe resulting changes in composition is such as
35、 to require the utmost precaution and the most meticulous care in the handling ofsamples. (WarningExtremely flammable, harmful if inhaled or ingested. Skin irritant on repeated contact. Aspiration hazard.)8.1.2 The size of the sample container from which the sample is taken shall be 1 L (1 qt). It s
36、hall be 70 % to 80 % filled withsample.8.1.3 The precision statement will be derived using samples in 1 L (1 qt) containers. However, samples taken in containers ofother sizes as prescribed in Practice D4057 can be used if it is recognized that the precision could be affected. In the case of referee
37、testing, the 1 L (1 qt) sample is mandatory.8.1.4 Perform the T(V/L) determination on the first test specimen withdrawn from the sample container. Do not use the remainingsample in the container for a second T(V/L) determination. If a second determination is necessary, obtain a new sample.8.1.5 Prot
38、ect samples from excessive temperature prior to testing. This can be accomplished by storage in an appropriate icebath or refrigerator.8.1.6 Do not test samples stored in leaky containers. Discard and obtain a new sample if leaks are detected.8.2 Sampling Handling TemperatureCoolPlace the sample con
39、tainer and contents in an icedice bath or refrigerator to between0 C and 1 C (32 F to 34 F) the 0 C to 1 C (32 F to 34 F) range prior to opening the sample container. EnsureAllow sufficienttime to reach this temperature by direct measurement of the temperature of a similar liquid in a like container
40、 placed in the coolingbath at the same time as the sample.temperature.NOTE 6One way to verify the sample temperature is by direct measurement of the temperature of a similar liquid in a similar container placed inthe cooling bath or refrigerator at the same time as the sample. Alternatively, tempera
41、ture-monitoring studies conducted by laboratories have determinedthe minimum amount of time necessary to achieve the required temperature requirements stated in 8.2, based upon typical sample receipt temperaturesand cooling capacities of the instrumentation employed by the laboratory on samples incl
42、uded in such studies. The results of such studies havesubsequently been applied to additional samples submitted for analysis. Typical minimum time durations reported by laboratories have ranged betweenapproximately 30 min and 45 min, however, laboratories choosing this option need to determine the m
43、inimum cooling time required for their specificoperation by conducting their own temperature-monitoring study.8.3 Verification of Sample Container Filling:8.3.1 With the sample at a temperature of 0 C to 1 C, take the container from the cooling bath or refrigerator and wipe drywith absorbent materia
44、l. If the container is not transparent, unseal it and using a suitable gage, confirm that the sample volumeequals 70 % to 80 % of the container capacity (see Note 57). If the sample is contained in a transparent glass container, verify thatthe container is 70 % to 80 % full by suitable means (see No
45、te 57).8.3.2 Discard the sample if the container is filled to less than 70 % by volume of the container capacity.8.3.3 If the container is filled to more than 80 % by volume, pour out enough sample to bring the container contents to withinthe 70 % to 80 % by volume range. Do not return any sample to
46、 the container once it has been withdrawn.NOTE 7For non-transparent containers, one way to confirm that the sample volume equals 70 % to 80 % of the container capacity is to use a dipstickthat has been pre-marked to indicate the 70 % and 80 % container capacities. The dipstick should be of such mate
47、rial that it shows wetting after beingimmersed and withdrawn from the sample. To confirm the sample volume, insert the dipstick into the sample container so that it touches the bottom ofthe container at a perpendicular angle, before removing the dipstick. For transparent containers, using a marked r
48、uler or by comparing the samplecontainer to a like container which has the 70 % and 80 % levels clearly marked, has been found suitable.8.3.4 Reseal the container, if necessary, and return the sample container to the cooling bath or refrigerator.8.4 Air Saturation of the Sample in the Sample Contain
49、er:8.4.1 Transparent Container OnlySince 8.3.1 does not require that the sample container be opened to verify the samplecapacity, it is necessary to unseal the cap momentarily before resealing it, so that samples in transparent containers are treated thesame as samples in non-transparent containers.8.4.2 With the sample again at a temperature of 0 C to 1 C, take the container from the cooling bath or refrigerator, wipe itdry with an absorbent material, remove the cap momentarily, taking care that no water enters, reseal and shak
