ASTM D5188-99
(Test Method)Standard Test Method for Vapor-Liquid Ratio Temperature Determination of Fuels (Evacuated Chamber Method)
Standard Test Method for Vapor-Liquid Ratio Temperature Determination of Fuels (Evacuated Chamber Method)
SCOPE
1.1 This test method covers the determination of the temperature at which the vapor formed from a selected volume of volatile petroleum product saturated with air at 0 to 1°C (32 to 34°F) produces a pressure of one atmosphere in an evacuated chamber of fixed volume. This test method is applicable to samples for which the determined temperature is between 36 and 80°C (97 and 176°F) and the vapor-liquid ratio is between 8 to 1 and 75 to 1. Note 1-When the vapor-liquid ratio is 20:1, the result is intended to be comparable to the results determined by Test Method D2533. Note 2-This test method may also be applicable at pressures other than one atmosphere, but the stated precision may not apply.
1.2 This test method is applicable to both gasoline and gasoline-oxygenate blends.
1.3 The values stated in SI units are to be regarded as the 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 warnings, see Notes 5 and 6.
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An American National Standard
Designation: D 5188 – 99
Standard Test Method for
Vapor-Liquid Ratio Temperature Determination of Fuels
(Evacuated Chamber Method)
This standard is issued under the fixed designation D 5188; 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.
1. Scope D 4057 Practice for Manual Sampling of Petroleum and
Petroleum Products
1.1 This test method covers the determination of the tem-
perature at which the vapor formed from a selected volume of
3. Terminology
volatile petroleum product saturated with air at 0 to 1°C (32 to
3.1 Definitions of Terms Specific to This Standard:
34°F) produces a pressure of one atmosphere in an evacuated
3.1.1 T , n—the equilibrium temperature at which
(V/L 5 20)
chamber of fixed volume. This test method is applicable to
the partial pressure of a sample under test conditions is equal
samples for which the determined temperature is between 36
to 101.3 kPa (14.69 psia) and the vapor-liquid ratio is 20.
and 80°C (97 and 176°F) and the vapor-liquid ratio is between
3.1.2 vapor-liquid ratio of a fuel, n—the ratio at a specified
8 to 1 and 75 to 1.
temperature and pressure of the volume of vapor in equilibrium
NOTE 1—When the vapor-liquid ratio is 20:1, the result is intended to
with liquid to the volume of sample charged, as a liquid, at 0°C
be comparable to the results determined by Test Method D 2533.
(32°F).
NOTE 2—This test method may also be applicable at pressures other
than one atmosphere, but the stated precision may not apply.
4. Summary of Test Method
1.2 This test method is applicable to both gasoline and
4.1 A known volume of chilled, air-saturated sample is
gasoline-oxygenate blends.
introduced into an evacuated, thermostatically controlled test
1.2.1 Some gasoline-oxygenate blends may show a haze
chamber of known volume. The sample volume is calculated to
when cooled to 0 to 1°C. If a haze is observed in 11.5, it shall
give the desired vapor-liquid ratio for the chamber volume in
be indicated in the reporting of results. The precision and bias
use. After injection, the chamber temperature is adjusted until
statements for hazy samples have not been determined (see
a stable chamber pressure of 101.3 kPa (14.69 psia) is
Note 11).
achieved.
1.3 The values stated in SI units are to be regarded as the
standard. The inch-pound units given in parentheses are 5. Significance and Use
provided for information only.
5.1 The tendency of a fuel to vaporize in automotive engine
1.4 This standard does not purport to address all of the
fuel systems is indicated by the vapor-liquid ratio of the fuel.
safety concerns, if any, associated with its use. It is the
5.2 Automotive fuel specifications generally include T
(V/
responsibility of the user of this standard to establish appro-
L 5 20) limits to ensure products of suitable volatility perfor-
priate safety and health practices and determine the applica-
mance. For high ambient temperatures, a fuel with a high value
bility of regulatory limitations prior to use. For specific
of T , indicating a fuel with a low tendency to
(V/L 5 20)
warnings, see Note 5 and Note 6.
vaporize, is generally specified; conversely for low ambient
temperatures, a fuel with a low value of T is specified.
(V/L 5 20)
2. Referenced Documents
2.1 ASTM Standards: 6. Apparatus
D 2533 Test Method for Vapor-Liquid Ratio of Spark-
6.1 Apparatus suitable for use shall employ a small volume
Ignition Engine Fuels
test chamber incorporating a transducer for pressure measure-
ments and associated equipment for thermostatically control-
ling the chamber temperature, evacuating the test chamber
This test method is under the jurisdiction of ASTM Committee D-2 on
prior to sample introduction, and cleaning and purging the
Petroleum Products and Lubricantsand is the direct responsibility of Subcommittee
D02.08on Volalitity.
Current edition approved Jan. 10, 1999. Published March 1999. Originally
published as D 5188 – 91. Last previous edition D 5188 – 98.
2 3
Annual Book of ASTM Standards, Vol 05.01. Annual Book of ASTM Standards, Vol 05.02.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 5188
chamber following the test. Critical elements of the apparatus sufficient purity to permit its use without lessening the accu-
shall meet the following specifications: racy of the determination. Reagents used for performance
6.1.1 Test Chamber, constructed of stainless steel or alumi- checks (see 10.3) shall be of at least 99 % purity.
num, designed to contain between 5 and 50 mL of liquid plus
7.2 n -Pentane, (Warning—see Note 5).
vapor with a tolerance of 6 1 % of the nominal capacity.
NOTE 5—Warning: Flammable, health hazard.
NOTE 3—The test chamber volumes of the instruments used for the
1991 cooperative test program to determine the precision and bias
8. Sampling
statements were between 5 and 15 mL of liquid plus vapor with a tolerance
8.1 General:
of6 1 % of the nominal capacity.
8.1.1 Conduct bulk sampling to obtain the laboratory
6.1.2 Pressure Transducer, minimum operational range
samples in accordance with Practice D 4057 except for
from 1 to 177 kPa (0 to 25.6 psia) with minimum resolution of
gasoline-oxygenate blends where water displacement is not
0.1 kPa (0.01 psi) and minimum accuracy of 6 0.8 kPa (6 0.12
used. The extreme sensitivity of T measurements to losses
(V/L)
psi). The pressure measurement system shall include associ-
through evaporation and the resulting changes in composition
ated electronics and readout devices to display the resulting
is such as to require the utmost precaution and the most
pressure reading.
meticulous care in the handling of samples.
6.1.3 Heater, thermostatically controlled heater capable of
maintaining the test chamber within 0.1°C of the set tempera-
NOTE 6—Warning: Extremely flammable, harmful if inhaled or in-
ture for a minimum of 5 min. gested. Skin irritant on repeated contact. Aspiration hazard.
NOTE 4—The use of automated instruments that automatically adjust 8.1.2 The size of the sample container from which the
the temperature, after sample injection, to give a pressure of 101.3 kPa
sample is taken shall be 1 L (1 qt). It shall be 70 to 80 % filled
(14.69 psia) is allowed.
with sample.
6.1.4 Platinum Resistance Thermometer, used to measure
8.1.3 The precision statement will be derived using samples
the temperature of the test chamber, having a minimum
in 1-L (1-qt) containers. However, samples taken in containers
temperature range of 36 to 80°C, minimum resolution of 0.1°C
of other sizes as prescribed in Practice D 4057 can be used if
(0.2°F) and minimum accuracy of 6 0.1°C (6 0.2°F).
it is recognized that the precision could be affected. In the case
6.2 Vacuum Pump, capable of reducing the pressure in the
of referee testing, the 1-L (1-qt) sample is mandatory.
test chamber to less than 0.01 kPa (0.001 psia).
8.1.4 Perform the T determination on the first test
(V/L)
6.3 Syringes, (if required for sample introduction), gas-
specimen withdrawn from the sample container. Do not use the
tight, 1- to 20-mL capacity with minimum accuracy and
remaining sample in the container for a second T deter-
(V/L)
precision of 6 1%.
mination. If a second determination is necessary, obtain a new
6.4 Bath, iced water or air, for chilling the samples and
sample.
syringe (if required) to between 0 and 1°C (32 to 34°F).
8.1.5 Protect samples from excessive temperature prior to
6.5 Pressure Measuring Device, capable of measuring local
testing. This can be accomplished by storage in an appropriate
station pressure with an accuracy of 0.20 kPa (0.03 psi) or
ice bath or refrigerator.
better, at the same elevation relative to sea level as the
8.1.6 Do not test samples stored in leaky containers. Discard
apparatus in the laboratory.
and obtain a new sample if leaks are detected.
6.5.1 When a mercury manometer is not used as the
8.2 Sampling Temperature—Cool the sample container and
pressure measuring device, the calibration of the pressure
contents in an iced bath or refrigerator to between 0 and 1°C
measuring device employed shall be periodically checked
(32 to 34°F) prior to opening the sample container. Ensure
(with traceability to a nationally recognized standard) to ensure
sufficient time to reach this temperature by direct measurement
that the device remains within the required accuracy specified
of the temperature of a similar liquid in a like container placed
in 6.5.
in the cooling bath at the same time as the sample.
6.6 McLeod Vacuum Gage, capable of measuring between 0
8.3 Verification of Sample Container Filling:
and 0.67 kPa (0 to 5 mm Hg).
8.3.1 With the sample at a temperature of 0 to 1°C, take the
7. Reagents and Materials container from the cooling bath or refrigerator and wipe dry
with absorbent material. If the container is not transparent,
7.1 Purity of Reagents—Unless otherwise indicated, all
unseal it and using a suitable gage, confirm that the sample
reagents shall conform to the specifications of the Committee
4 volume equals 70 to 80 % of the container capacity (see Note
on Analytical Reagents of the American Chemical Society
7). If the sample is contained in a transparent glass container,
where such specifications are available. Lower purities can be
verify that the container is 70 to 80 % full by suitable means
used, provided it is first ascertained that the reagent is of
(see Note 7).
8.3.2 Discard the sample if the container is filled to less than
70 % by volume of the container capacity.
Reagent Chemicals, American Chemical Society Specifications, American
Chemical Society, Washington, DC. For suggestions on the testing of reagents not
8.3.3 If the container is filled to more than 80 % by volume,
listed by the American Chemical Society, see Analar Standards for Laboratory
pour out enough sample to bring the container contents to
Chemicals, BDH Ltd., Poole, Dorset, U.K., and the United States Pharmacopeia
within the 70 to 80 % by volume range. Do not return any
and National Formulary, U.S. Pharmacopeial Convention, Inc. (USPC), Rockville,
MD. sample to the container once it has been withdrawn.
D 5188
NOTE 7—For non-transparent containers, one way to confirm that the
(0.8 mm Hg) adjust the indicator to zero or to the actual
sample volume equals 70 to 80 % of the container capacity is to use a
reading on the McLeod gage as dictated by the instrument
dipstick that has been pre-marked to indicate the 70 and 80 % container
design and manufacturer’s instructions.
capacities. The dipstick should be of such material that it shows wetting
10.1.2 Open the test chamber to the atmosphere and observe
after being immersed and withdrawn from the sample. To confirm the
sample volume, insert the dipstick into the sample container so that it the indicator reading. If the pressure reading is not equal to the
touches the bottom of the container at a perpendicular angle, before
ambient barometric pressure, adjust the indicator span control
removing the dipstick. For transparent containers, using a marked ruler or
until the appropriate reading is observed. Ensure that the
by comparing the sample container to a like container which has the 70
instrument is set to display the total pressure and not a
and 80 % levels clearly marked, has been found suitable.
calculated or corrected value.
8.3.4 Reseal the container, if necessary, and return the
10.1.3 Repeat 10.1.1 and 10.1.2 until the zero and baromet-
sample container to the cooling bath or refrigerator.
ric pressure read correctly without further adjustments.
8.4 Air Saturation of the Sample in the Sample Container:
10.2 Calibrate the platinum resistance thermometer and
8.4.1 Transparent Container Only—Since 8.3.1 does not
indicator used to monitor the temperature of the test chamber
require that the sample container be opened to verify the
at least every six months against a National Institute of
sample capacity, it is necessary to unseal the cap momentarily
Standards and Technology (NIST) traceable thermometer.
before resealing it, so that samples in transparent containers are
treated the same as samples in non-transparent containers. 10.3 Check the performance of the instrument each day it is
in use by running a sample consisting of air saturated
8.4.2 With the sample again at a temperature of 0 to 1°C,
take the container from the cooling bath or refrigerator, wipe it n-pentane, T 5 36.1°C (96.9°F). Handle the perfor-
(V/L 5 20)
dry with an absorbent material, remove the cap momentarily, mance check material in the same manner as a sample (see
taking care that no water enters, reseal and shake vigorously. Sections 8 and 11). If the observed T differs by more
V/L 5 20
Return it to the bath or refrigerator for a minimum of 2 min. than 0.5°C (1.0°F), check the instrument calibration (see 10.1
and 10.2).
9. Preparation of Apparatus
NOTE 9—Other pure compounds having vapor pressures within the
9.1 Prepare the instrument for operation in accordance with
range of fuels to be tested may be used.
the manufacturer’s instructions.
9.2 Clean and dry the test chamber to avoid contamination
11. Procedure
of the test sample.
11.1 Calculate the volume of sample required to give the
9.3 Prior to sample introduction, visually determine from
desired vapor-liquid ratio using Eq 1 (12.1).
the instrument display that the test chamber pressure is stable
11.2 Remove the sample from the cooling bath or refrigera-
and does not exceed 0.1 kPa (0.01 psia). If the pressure is not
tor, dry the exterior of the container with absorbent material,
stable or exceeds this value, check that the chamber contains
unseal and insert a chilled transfer tube or gas-tight syringe
no volatile materials from a previous sample, the seals are
satisfactory, the calibration of the transducer is correct, and the (9.4). Draw a bubble-free aliquot of sample into the syringe or
transfer tube and deliver this sample to the test chamber as
apparatus does not leak.
9.4 If a syringe is used for introduction of the sample, chill rapidly as possible. The total time between opening the chilled
the syringe to between 0 and 1.0°C (32 to 34°F) in a sample container and inserting/securing the syringe into the
refrigerator or ice bath before drawing in the sample. The sealed test chamber shall not exceed 1 min.
syringe must be kept completely dry during this cooling. Place
11.3 Perform the analysis in accordance with the manufac-
the clean and dry syringe in a water tight
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