ASTM D6378-10(2016)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D6378 − 10 (Reapproved 2016)
Standard Test Method for
Determination of Vapor Pressure (VP ) of Petroleum
X
Products, Hydrocarbons, and Hydrocarbon-Oxygenate
Mixtures (Triple Expansion Method)
This standard is issued under the fixed designation D6378; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the use of automated vapor
responsibility of the user of this standard to establish appro-
pressureinstrumentstodeterminethevaporpressureexertedin
priate safety and health practices and determine the applica-
vacuum by volatile, liquid petroleum products, hydrocarbons,
bility of regulatory limitations prior to use. For specific
and hydrocarbon-oxygenate mixtures. This test method is
warning statements, see 7.2 – 7.8.
suitable for testing samples with boiling points above 0°C
(32°F) that exert a vapor pressure between 7kPa and 150kPa
2. Referenced Documents
(1.0psi and 21psi) at 37.8°C (100°F) at a vapor-to-liquid
2.1 ASTM Standards:
ratio of 4:1. The liquid sample volume size required for
D323TestMethodforVaporPressureofPetroleumProducts
analysis is dependent upon the vapor-to-liquid ratio chosen
(Reid Method)
(see Note 1) and the measuring chamber volume capacity of
D2892Test Method for Distillation of Crude Petroleum
the instrument (see 6.1.1 and Note 3).
(15-Theoretical Plate Column)
NOTE 1—The test method is suitable for the determination of the vapor
D4057Practice for Manual Sampling of Petroleum and
pressure of volatile, liquid petroleum products at temperatures from 0°C
Petroleum Products
to 100°C at vapor to liquid ratios of 4:1 to 1:1 (X=4to1)and pressures
D4177Practice for Automatic Sampling of Petroleum and
up to 500kPa (70psi), but the precision statement (see Section 16) may
Petroleum Products
not be applicable.
D4953Test Method for Vapor Pressure of Gasoline and
1.2 Thistestmethodalsocoverstheuseofautomatedvapor
Gasoline-Oxygenate Blends (Dry Method)
pressureinstrumentstodeterminethevaporpressureexertedin
D5191Test Method for Vapor Pressure of Petroleum Prod-
vacuum by aviation turbine fuels. This test method is suitable
ucts (Mini Method)
for testing aviation turbine fuel samples with boiling points
D5842Practice for Sampling and Handling of Fuels for
above 0°C (32°F) that exert a vapor pressure between 0kPa
Volatility Measurement
and 110kPa (0psi and 15.5psi) at a vapor-to-liquid ratio of
D5854Practice for Mixing and Handling of Liquid Samples
4:1, in the temperature range from 25°C to 100°C (77°F to
of Petroleum and Petroleum Products
212°F).
D6299Practice for Applying Statistical Quality Assurance
1.3 The vapor pressure (VP ) determined by this test
X
and Control Charting Techniques to Evaluate Analytical
method at a vapor-liquid ratio of 4:1 (X = 4) of gasoline and
Measurement System Performance
gasoline-oxygenate blends at 37.8°C can be correlated to the
D6300Practice for Determination of Precision and Bias
dry vapor pressure equivalent (DVPE) value determined by
Data for Use in Test Methods for Petroleum Products and
Test Method D5191 (see 16.3). This condition does not apply
Lubricants
when the sample is aviation turbine fuel.
D6708Practice for StatisticalAssessment and Improvement
of Expected Agreement Between Two Test Methods that
1.4 The values stated in SI units are to be regarded as the
standard. The values given in parentheses are for information Purport to Measure the Same Property of a Material
only.
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.08 on Volatility. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Oct. 1, 2016. Published November 2016. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1999. Last previous edition approved in 2010 as D6378–10 DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D6378-10R16. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6378 − 10 (2016)
3.1.1 dry vapor pressure equivalent (DVPE)—a value cal- associated equipment to control the chamber temperature
culated by a correlation equation from the total pressure (Test within the range from 0°C to 100°C.The measuring chamber
Method D5191), which is equivalent to the value obtained on
shall contain a movable piston with a maximum dead volume
the sample by Test Method D4953, Procedure A.
of less than 1% of the total volume at the lowest position to
allow sample introduction into the measuring chamber and
3.1.2 partial pressure from dissolved air (PPA), n—the
expansion to the desired vapor-liquid ratio. A static pressure
pressure exerted in vacuum from dissolved air that escapes
transducer shall be incorporated in the piston. The measuring
from the liquid phase into the vapor phase.
chamber shall contain an inlet/outlet valve combination for
3.1.3 Reid vapor pressure equivalent (RVPE)—a value cal-
sample introduction and expulsion. The piston and the valve
culated by a correlation equation from the TP , which is
X
combinationshallbeatthesametemperatureasthemeasuring
equivalenttothevalueobtainedonthesamplebyTestMethod
chamber to avoid any condensation or excessive evaporation.
D323.
6.1.1 The measuring chamber shall be designed to contain
3.1.4 total pressure (TP ), n—the pressure exerted in
X
between5mLand15mLofliquidandvaporandbecapableof
vacuum by air- and gas-containing petroleum products, com-
maintaining a vapor-liquid ratio of 4:1 to 1:1. The accuracy of
ponents and feedstocks, and other liquids, in the absence of
the adjusted vapor-liquid ratio shall be within 0.05.
undissolved water at a vapor-liquid ratio of X:1.
3.1.5 vapor pressure (VP ), n—the total pressure minus the
X
NOTE 3—The measuring chamber employed by the instruments used in
PPA in the liquid at a vapor-liquid ratio of X:1.
generating the precision and bias statements were constructed of nickel
plated aluminum and stainless steel with a total volume of 5mL.
VP 5TP 2PPA (1)
X X
Measuring chambers exceeding a 5mL capacity can be used, but the
precision and bias statements (see Section 16) are not known to apply.
4. Summary of Test Method
4.1 Employing a measuring chamber with a built-in piston, 6.1.2 The pressure transducer shall have a minimum opera-
a sample of known volume is drawn into the temperature
tional range from 0kPa to 200kPa (0psi to 29psi) with a
controlled chamber at 20°C or higher. After sealing the minimum resolution of 0.1kPa (0.01psi) and a minimum
chamber, the temperature of the chamber is increased to a
accuracy of 60.2kPa (60.03psi). The pressure measurement
specified value simultaneously with the first expansion. Two
systemshallincludeassociatedelectronicsandreadoutdevices
further expansions are performed to a final volume of (X+1)
to display the resulting pressure reading.
times that of the test specimen.After each expansion, the TP
X
6.1.3 Electronic temperature control shall be used to main-
isdetermined.ThePPAandthesolubilityofairinthespecimen
tain the measuring chamber at the prescribed temperature
are calculated from the three resulting pressures. The (VP )is
X
within 60.1°Cforthedurationofthevaporpressuremeasure-
calculated by subtracting the PPA in the liquid from TP .
X
ment.
NOTE 2—For liquids containing very low levels of high vapor pressure
6.1.4 A platinum resistance thermometer shall be used for
contaminants, which behave like a gas, this test method of determination
of the PPAand gases may lead to wrong results since the partial pressure measuring the temperature of the measuring chamber. The
ofthecontaminantswillbeincludedinthePPA.Thiseffectisshownwhen
minimum temperature range of the measuring device shall be
the value of the PPA and gases exceeds the average maximum limit of
from 0°C to 100°C with a resolution of 0.1°C and an
7kPa (1psi).
accuracy of 60.1°C.
5. Significance and Use
6.1.5 Thevaporpressureapparatusshallhaveprovisionsfor
5.1 Vapor pressure is a very important physical property of
rinsing the measuring chamber with a solvent of low vapor
volatile liquids for shipping and storage.
pressure or with the next sample to be tested.
5.2 The vapor pressure of gasoline and gasoline-oxygenate
6.2 Vacuum Pump for Calibration, capable of reducing the
blends is regulated by various government agencies.
pressure in the measuring chamber to less than 0.01kPa
5.3 Specifications for volatile petroleum products generally
(0.001psi) absolute.
include vapor pressure limits to ensure products of suitable
6.3 McLeod Vacuum Gauge or Calibrated Electronic
volatility performance.
Vacuum Measuring Device for Calibration,tocoveratleastthe
5.4 In this test method, an air saturation procedure prior to
range from 0.01kPa to 0.67kPa (0.1mm to 5mm Hg). The
the measurement is not required, thus eliminating losses of
calibration of the electronic vacuum measuring device shall be
high volatile compounds during this step. This test method is
regularly verified in accordance with Annex A6.3 on Vacuum
faster and minimizes potential errors from improper air satu-
Sensors in Test Method D2892.
ration. This test method permits VP determinations in the
X
6.4 Pressure Measuring Device for Calibration, capable of
field.
measuring local station pressure with an accuracy and a
5.5 Thistestmethodcanbeappliedinonlineapplicationsin
resolution of 0.1kPa (1mm Hg), or better, at the same
which an air saturation procedure prior to the measurement
elevationrelativetosealevelastheapparatusinthelaboratory.
cannot be performed.
NOTE 4—This test method does not give full details of instruments
6. Apparatus
suitableforcarryingoutthistest.Detailsontheinstallation,operation,and
6.1 The apparatus suitable for this test method employs a
maintenance of each instrument may be found in the manufacturer’s
small volume, cylindrically shaped measuring chamber with manual.
D6378 − 10 (2016)
TABLE 1 Accepted Reference Value (ARV) and Acceptable Testing Range for Reference Fluids (Note 16)
Recommended Instrument Acceptable Testing Range for
ARV [VP (37.8 °C)] ± Uncertainty,
Reference Fluid Manufacturer Tolerance, Reference Fuel [VP (37.8 °C)],
(kPa)
(kPa) (kPa)
Pentane 107.9 ± 0.2 ±1.0 107.9 ± 1.2 (106.7 to 109.1)
2,2 Dimethylbutane 68.8 ± 0.2 ±1.0 68.8 ± 1.2 (67.6 to 70.0)
2,3 Dimethylbutane 51.7 ± 0.2 ±1.0 51.7 ± 1.2 (50.5 to 52.9)
Recommended Instrument Acceptable Testing Range for
ARV [VP (37.8 °C)] ± Uncertainty,
(37.8 °C)],
Reference Fluid Manufacturer Tolerance, Reference Fuel [VP
(psi)
(psi) (psi)
Pentane 15.65 ± 0.03 ±0.14 15.65 ± 0.17 (15.48 to 15.82)
2,2 Dimethylbutane 9.98 ± 0.03 ±0.14 9.98 ± 0.17 (9.81 to 10.15)
2,3 Dimethylbutane 7.50 ± 0.03 ±0.14 7.50 ± 0.17 (7.33 to 7.67)
7. Reagents and Materials 8. Sampling and Sample Introduction
7.1 Purity of Reagents—Use chemicals of at least 99% 8.1 General Requirements:
purity for verification of instrument performance (see Section 8.1.1 The extreme sensitivity of vapor pressure measure-
11). Unless otherwise indicated, it is intended that all reagents ments to losses through evaporation and the resulting changes
conform to the specifications of the Committee of Analytical in composition is such as to require the utmost precaution and
Reagents of the American Chemical Society where such the most meticulous care in the drawing and handling of
specifications are available. Lower purities can be used, samples.
provided it is first ascertained that the reagent is of sufficient 8.1.2 Obtainasampleandtestspecimeninaccordancewith
purity to permit its use without lessening the accuracy of the Practice D4057, D4177, D5842,or D5854 when appropriate,
determination. exceptdonotusetheSamplingbyWaterDisplacementsection
7.1.1 The chemicals in 7.3, 7.4, and 7.7 are suggested for for fuels containing oxygenates. Use either a 250mL or 1L
verification of instrument performance (see Section 11), based (1qt) sized container filled between 70% and 80% with
on the reference fuels analyzed in the 2003 interlaboratory sample. See Note 6 on effect of sample size on testing
study (ILS) (see 16.1, Table 1, and Note 16). Such reference precision.
fuels are not to be used for instrument calibration. Table 1 8.1.2.1 When the sample is aviation turbine fuel, use of
identifies the accepted reference value (ARV) and uncertainty 100mL size containers are suitable when they are filled to a
limits, as well as the acceptable testing range for each of the minimum of 80%.
reference fuels listed.
NOTE 6—The current precision statements for gasoline and gasoline-
oxygenate blends were derived from the 2003 ILS (see 16.1) using
NOTE 5—Verification fluids reported by 12 of the D6378 data set
samples in 250mL and 1L (1qt) clear glass containers. However,
participants in the 2003 ILS (see 16.1) included the following (with
samples in containers of other sizes as prescribed in Practice D4057 may
number of data sets identified in parentheses): 2,2-dimethylbutane (11),
be used, with the same filling requirement, but the precision can be
and 2,3-dimethylbutane (1).
affected. The differences in precision results obtained from 250mL and
7.2 Cyclopentane, (Warning—Cyclopentane is flammable
1L containers were found to be statistically significant, in addition to
and a health hazard).
having a statistically observable bias being detected between 250mLand
1L containers. See Tables2 and 3, as well as Figs. 1 and 2 for more
7.3 2,2-Dimethylbutane, (Warning—2,2-dimethylbutane is
specificdetailsonprecisiondifferencesasafunctionofVP (37.8°C)and
flammable and a health hazard).
container size, as well as 16.3.3 for specific details on the relative bias
between 250mL and 1L containers. In general, numerically better
7.4 2,3-Dimethylbutane, (Warning—2,3-dimethylbutane is
repeatability values were determined at VP (37.8°C) values < 64.3kPa
flammable and a health hazard).
(9.3psi) for samples in 1L containers versus 250mL containers.
Secondly, numerically better reproducibility values were determined at
7.5 Methanol, (Warning—Methanol is flammable and a
VP (37.8°C) values < 60.2kPa (8.7psi) for samples in 1L containers
health hazard).
versus 250mL containers.
NOTE 7—The curren
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