ASTM D5191-99
(Test Method)Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method)
Standard Test Method for Vapor Pressure of Petroleum Products (Mini Method)
SCOPE
1.1 This test method covers the use of automated vapor pressure instruments to determine the total vapor pressure exerted in vacuum by air-containing, volatile, liquid petroleum products. This test method is suitable for testing samples with boiling points above 0oC (32oF) that exert a vapor pressure between 7 and 130 kPa (1.0 and 18.6 psi) at 37.8oC (100oF) at a vapor-to-liquid ratio of 4:1. Measurements are made on liquid sample sizes in the range from 1 to 10 mL. No account is made for dissolved water in the sample.
Note 1--Samples can also be tested at other vapor-to-liquid ratios, temperatures, and pressures, but the precision and bias statements need not apply.
1.1.1 Some gasoline-oxygenate blends may show a haze when cooled to 0 to 1oC. If a haze is observed in , it shall be indicated in the reporting of results. The precision and bias statements for hazy samples have not been determined (see Note 10).
1.2 This test method is suitable for calculation of the dry vapor pressure equivalent (DVPE) of gasoline and gasoline-oxygenate blends by means of a correlation equation (see ). The calculated DVPE very closely approximates the dry vapor pressure that would be obtained on the same material when tested by Test Method D4953.
1.3 The values stated in SI units are regarded as standard. The inch-pound units given in parentheses are provided for information only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific warning statements, see 7.2 through 7.7.
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Designation: D 5191 – 99 An American National Standard
Standard Test Method for
Vapor Pressure of Petroleum Products (Mini Method)
This standard is issued under the fixed designation D 5191; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope D 2892 Test Method for Distillation of Crude Petroleum
(15-Theoretical Plate Column)
1.1 This test method covers the use of automated vapor
D 4057 Practice for Manual Sampling of Petroleum and
pressure instruments to determine the total vapor pressure
Petroleum Products
exerted in vacuum by air-containing, volatile, liquid petroleum
D 4953 Test Method for Vapor Pressure of Gasoline and
products. This test method is suitable for testing samples with
Gasoline-Oxygenate Blends (Dry Method)
boiling points above 0°C (32°F) that exert a vapor pressure
D 5190 Test Method for Vapor Pressure of Petroleum Prod-
between 7 and 130 kPa (1.0 and 18.6 psi) at 37.8°C (100°F) at
ucts (Automatic Method)
a vapor-to-liquid ratio of 4:1. Measurements are made on liquid
sample sizes in the range from 1 to 10 mL. No account is made
3. Terminology
for dissolved water in the sample.
3.1 Definition of Terms Specific to This Standard:
NOTE 1—Samples can also be tested at other vapor-to-liquid ratios,
3.1.1 absolute pressure—the pressure of the air-free sample.
temperatures, and pressures, but the precision and bias statements need not
It is calculated from the total pressure of the sample by
apply.
subtracting out the partial pressure of the dissolved air.
1.1.1 Some gasoline-oxygenate blends may show a haze
3.1.2 dry vapor pressure equivalent (DVPE)—a value cal-
when cooled to 0 to 1°C. If a haze is observed in 8.5, it shall
culated by a correlation equation (see 13.2) from the total
be indicated in the reporting of results. The precision and bias
pressure.
statements for hazy samples have not been determined (see
3.1.2.1 Discussion—The DVPE is expected to be equivalent
Note 12).
to the value obtained on the sample by Test Method D 4953,
1.2 This test method is suitable for calculation of the dry
Procedure A.
vapor pressure equivalent (DVPE) of gasoline and gasoline-
3.1.3 total pressure—the observed pressure measured in the
oxygenate blends by means of a correlation equation (see
experiment that is the sum of the partial pressure of the sample
13.2). The calculated DVPE very closely approximates the dry
and the partial pressure of the dissolved air.
vapor pressure that would be obtained on the same material
4. Summary of Test Method
when tested by Test Method D 4953.
1.3 The values stated in SI units are regarded as standard.
4.1 A known volume of chilled, air-saturated sample is
The inch-pound units given in parentheses are provided for
introduced into an evacuated, thermostatically controlled test
information only.
chamber, the internal volume of which is five times that of the
1.4 This standard does not purport to address all of the
total test specimen introduced into the chamber. After injection
safety concerns, if any, associated with its use. It is the
into the test chamber, the test specimen is allowed to reach
responsibility of the user of this standard to establish appro-
thermal equilibrium at the test temperature, 37.8°C (100°F).
priate safety and health practices and determine the applica-
The resulting rise in pressure in the chamber is measured using
bility of regulatory limitations prior to use. For specific
a pressure transducer sensor and indicator. Only total pressure
warning statements, see Note 5.
measurements (sum of the partial pressure of the sample and
the partial pressure of the dissolved air) are used in this test
2. Referenced Documents
method, although some instruments can measure the absolute
2.1 ASTM Standards:
pressure of the sample as well.
4.2 The measured total vapor pressure is converted to a dry
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee
D02.08 on Volatility.
Current edition approved Dec. 10, 1998 and Jan. 10, 1999. Published March Annual Book of ASTM Standards, Vol 05.02.
1999. Originally published as D 5191 – 91. Last previous edition D 5191 – 96. Annual Book of ASTM Standards, Vol 05.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
D 5191
vapor pressure equivalent (DVPE) by use of a correlation better, at the same elevation relative to sea level as the
equation (see 13.2). apparatus in the laboratory.
6.5.1 When a mercury manometer is not used as the
5. Significance and Use
pressure measuring device, the calibration of the pressure
5.1 Vapor pressure is a very important physical property of
measuring device employed shall be periodically checked
volatile liquids.
(with traceability to a nationally recognized standard) to ensure
5.2 The vapor pressure of gasoline and gasoline-oxygenate
that the device remains within the required accuracy specified
blends is regulated by various government agencies.
in 6.5.
5.3 Specifications for volatile petroleum products generally
6.6 McLeod Vacuum Gage, to cover at least the range from
include vapor pressure limits to ensure products of suitable
0 to 0.67 kPa (0 to 5 mm Hg). Calibration of the McLeod gage
volatility performance.
is checked in accordance with Annex A6 of Test Method
5.4 This test method is more precise than Test Method
D 2892.
D 4953, uses a small sample size (1 to 10 mL), and requires
7. Reagents and Materials
about 7 min to complete the test.
7.1 Purity of Reagents—Use chemicals of at least 99 %
6. Apparatus
purity for quality control checks (see Section 10). Unless
6.1 Vapor Pressure Apparatus—The type of apparatus suit-
otherwise indicated, it is intended that all reagents conform to
able for use in this test method employs a small volume test
the specifications of the Committee on Analytical Reagents of
chamber incorporating a transducer for pressure measurements
the American Chemical Society where such specifications are
and associated equipment for thermostatically controlling the
available. Lower purities can be used, provided it is first
chamber temperature and for evacuating the test chamber prior
ascertained that the reagent is of sufficient purity to permit its
to sample introduction.
use without lessening the accuracy of the determination.
6.1.1 The test chamber shall be designed to contain between
NOTE 4—The chemicals in this section are suggested for use in quality
5 and 50 mL of liquid and vapor and be capable of maintaining
control procedures (see 11.2) and are not used for instrument calibration.
a vapor-to-liquid ratio between 3.95 to 1.00 and 4.05 to 1.00.
7.2 Cyclohexane (Warning—See Note 5.)
NOTE 2—The test chamber employed by the instruments used in
7.3 Cyclopentane (Warning—See Note 5.)
generating the precision and bias statements were constructed of stainless
7.4 2,2-Dimethylbutane (Warning—See Note 5.)
steel or aluminum.
7.5 2,3-Dimethylbutane (Warning—See Note 5.)
NOTE 3—Test chambers exceeding a 15 mL capacity can be used, but
the precision and bias statements (see Section 14) are not known to apply.
7.6 2-Methylpentane (Warning—See Note 5.)
7.7 Toluene (Warning—See Note 5.)
6.1.2 The pressure transducer shall have a minimum opera-
tional range from 0 to 177 kPa (0 to 25.7 psi) with a minimum
NOTE 5—Warning: Cyclohexane, toluene, cyclopentane, 2,2-
resolution of 0.1 kPa (0.01 psi) and a minimum accuracy of
dimethylbutane, 2,3-dimethylbutane, and 3-methylpentane are flammable.
60.8 kPa (60.12 psi). The pressure measurement system shall Health Hazard.
include associated electronics and readout devices to display
8. Sampling
the resulting pressure reading.
8.1 General Requirements:
6.1.3 A thermostatically controlled heater shall be used to
8.1.1 The extreme sensitivity of vapor pressure measure-
maintain the test chamber at 37.8 6 0.1°C (100 6 0.2°F) for
ments to losses through evaporation and the resulting changes
the duration of the test.
in composition is such as to require the utmost precaution and
6.1.4 A platinum resistance thermometer shall be used for
the most meticulous care in the drawing and handling of
measuring the temperature of the test chamber. The minimum
samples.
temperature range of the measuring device shall be from
8.1.2 Obtain a sample and test specimen in accordance with
ambient to 75°C (167°F) with a resolution of 0.1°C (0.2°F) and
Practice D 4057, except do not use the “Sampling by Water
an accuracy of 0.1°C (0.2°F).
Displacement” section for fuels containing oxygenates. Use a 1
6.1.5 The vapor pressure apparatus shall have provisions for
L (1 qt) sized container filled between 70 and 80 with sample.
introduction of the test specimen into an evacuated test
chamber and for the cleaning or purging of the chamber
NOTE 6—The present precision statement was derived using samples in
following the test.
1 L (1 qt) containers. However, samples in containers of other sizes, as
6.2 Vacuum Pump, capable of reducing the pressure in the prescribed in Practice D 4057, can be used, with the same ullage
requirement, if it is recognized that the precision can be affected.
test chamber to less than 0.01 kPa (0.001 psi) absolute.
6.3 Syringe, (optional, depending on sample introduction
8.1.3 In the case of referee testing, the 1 L (1 qt) sample
mechanism employed with each instrument) gas-tight, 1 to 20
container is mandatory.
mL capacity with a 61 % or better accuracy and a 61% or
better precision. The capacity of the syringe should not exceed
two times the volume of the test specimen being dispensed.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
6.4 Iced Water Bath or Air Bath, for chilling the samples
listed by the American Chemical Society, see Analar Standards for Laboratory
and syringe to temperatures between 0 to 1°C (32 to 34°F).
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
6.5 Pressure Measuring Device, capable of measuring local
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
station pressure with an accuracy of 0.20 kPa (0.03 psi), or MD.
D 5191
8.1.4 Perform the vapor pressure determination on the first test specimen and injecting it into the instrument for analysis,
test specimen withdrawn from a sample container. Do not use check the remaining sample for phase separation. If the sample
the remaining sample in the container for a second vapor is contained in a transparent container, this observation can be
pressure determination. If a second determination is necessary, made prior to sample transfer. If the sample is contained in a
obtain a new sample. non-transparent container, mix the sample thoroughly and
8.1.5 Protect samples from excessive temperatures prior to immediately pour a portion of the remaining sample into a
testing. This can be accomplished by storage in an appropriate clear glass container and observe for evidence of phase
ice bath or refrigerator. separation. A hazy appearance is to be carefully distinguished
8.1.6 Do not test samples stored in leaky containers. Discard from separation into two distinct phases. The hazy appearance
and obtain a new sample if leaks are detected. shall not be considered grounds for rejection of the fuel. If a
second phase is observed, discard the test and the sample. Hazy
8.2 Sampling Handling Temperature— Cool the sample
container and contents in an ice bath or refrigerator to the 0 to samples may be analyzed (see Report section ).
1°C (32 to 34°F) range prior to opening the sample container.
9. Preparation of Apparatus
Allow sufficient time to reach this temperature. Verify the
9.1 Prepare the instrument for operation in accordance with
sample temperature by direct measurement of the temperature
the manufacturer’s instructions.
of a similar liquid in a similar container placed in the cooling
9.2 Clean and dry the test chamber as required to avoid
bath or refrigerator at the same time as the sample.
contamination of the test specimen. Prior to sample introduc-
8.3 Verification of Sample Container Filling—With the
tion, visually determine from the instrument display that the
sample at a temperature of 0 to 1°C, take the container from the
test chamber pressure is stable and does not exceed 0.1 kPa
cooling bath or refrigerator, and wipe dry with absorbent
(0.01 psi). When the pressure is not stable or exceeds this
material. If the container is not transparent, unseal it and using
value, check that the chamber is clean of volatile materials
a suitable gage, confirm that the sample volume equals 70 to
remaining in the chamber from a previous sample or check the
80 % of the container capacity (see Note 7). If the sample is
calibration of the transducer.
contained in a transparent glass container, verify that the
9.3 If a syringe is used for introduction of the sample
container is 70 to 80 % full by suitable means (see Note 7).
specimen, chill it to between 0 and 4.5°C (32 and 40°F) in a
8.3.1 Discard the sample if the container is filled to less than
refrigerator or ice bath before drawing in the sample. Avoid
70 %, by volume, of the container capacity.
water contamination of the syringe reservoir by sealing the
8.3.2 If the container is more than 80 % by volume full,
outlet of the syringe during the cooling process.
pour out enough sample to bring the container contents within
9.4 Prior to introduction of the test specimen, check that the
the 70 to 80 % by volume range. Do not return any sample to
temperature of the test chamber is within the required range of
the container once it has been withdrawn.
37.86 0.1°C (100 6 0.2°F).
8.3.3 Reseal the container if necessary, and return the
sample container the cooling bath or refrigerator.
10. Calibration
NOTE 7—For non-transparent containers, one way to confirm that the
10.1 Pressure Transducer:
sample volume equals 70 to 80 % of the container capacity is to use a
10.1.1 Check the calibration of the transducer on a monthly
dipstick that has been pre-marked to indicate the 70 and 80 % container
basis or when needed as indicated from the quality control
capacities. The dipstick should be of such material that it shows wetting
checks (see Section 11). The calibration of the transducer is
after being immersed and withdrawn from the sample. To confi
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