ASTM D7777-13(2018)e1
(Test Method)Standard Test Method for Density, Relative Density, or API Gravity of Liquid Petroleum by Portable Digital Density Meter
Standard Test Method for Density, Relative Density, or API Gravity of Liquid Petroleum by Portable Digital Density Meter
SIGNIFICANCE AND USE
5.1 The density, relative density, or API gravity of petroleum products are important quality indicators and are used in quantity calculations or to satisfy application, transportation, storage, and regulatory requirements.
5.2 This test method should not be used to determine density for custody transfer quantity calculations, particularly where mass or weight is the unit of quantity measurement. Test Method D4052 is appropriate for these applications.
SCOPE
1.1 This test method covers the determination of the density, relative density, or API gravity of liquid petroleum products using portable digital density meters at test temperatures between 0 °C and 40 °C (32 °F to 104 °F). Its application is restricted to samples with a dry vapor pressure equivalent up to 80 kPa (11.6 psi) and a viscosity below 100 mm2/s (cSt) at the test temperature.
1.2 This test method is suitable for determining the density to the nearest 1 kg/m3. To determine the density to the nearest 0.1 kg/m3, use Test Method D4052.
1.3 This test method is easily calibrated and primarily suitable for field applications. It is important for the user to know and understand the electrical classification of the area in which the analyzer is to be used and to select an analyzer appropriate for that classification.
1.4 Test Methods D287, D1298, and D6822 are used in field applications. This test method provides an alternative field method that is easily calibrated and does not pose the hazard of hydrometer glass breakage present in current field methods.
1.5 Portable digital density meters measure the density and temperature of the filled-in sample at the sample temperature. The measured density and temperature are automatically converted into:
Density at 15 °C / density at 60 °F
Relative density 15 °C/15 °C / relative density 60 °F/60 °F
API gravity 15 °C / API gravity 60 °F
by the instrument using the calculation routines for Generalized Products as defined in Guide D1250.
1.6 If the density meter does not have in-built software to calculate the density at the reference temperature, this is calculated from the observed density at test temperature using the Petroleum Measurement Tables.
1.7 The accepted units of measure for density are kilograms per cubic metre (SI unit) or grams per cubic centimetre. Values in SI units are to be regarded as the standard. Values in parentheses are for information only. Both SI and customary units have been rounded; they may not be exactly equivalent.
1.8 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
General Information
Relations
Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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Designation: D7777 − 13 (Reapproved 2018)
Designation 559/12
Standard Test Method for
Density, Relative Density, or API Gravity of Liquid Petroleum
by Portable Digital Density Meter
This standard is issued under the fixed designation D7777; 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 (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—The formatting of SI units was corrected editorially in November 2018.
1. Scope by the instrument using the calculation routines for Gener-
alized Products as defined in Guide D1250.
1.1 Thistestmethodcoversthedeterminationofthedensity,
relative density, or API gravity of liquid petroleum products 1.6 If the density meter does not have in-built software to
calculate the density at the reference temperature, this is
using portable digital density meters at test temperatures
between 0 °C and 40 °C (32 °F to 104 °F). Its application is calculated from the observed density at test temperature using
the Petroleum Measurement Tables.
restricted to samples with a dry vapor pressure equivalent up to
80 kPa (11.6 psi) and a viscosity below 100 mm /s (cSt) at the
1.7 The accepted units of measure for density are kilograms
test temperature.
per cubic metre (SI unit) or grams per cubic centimetre.Values
in SI units are to be regarded as the standard. Values in
1.2 This test method is suitable for determining the density
parentheses are for information only. Both SI and customary
to the nearest 1 kg⁄m . To determine the density to the nearest
units have been rounded; they may not be exactly equivalent.
0.1 kg⁄m , use Test Method D4052.
1.8 This standard does not purport to address all of the
1.3 This test method is easily calibrated and primarily
safety concerns, if any, associated with its use. It is the
suitable for field applications. It is important for the user to
responsibility of the user of this standard to establish appro-
know and understand the electrical classification of the area in
priate safety, health, and environmental practices and deter-
which the analyzer is to be used and to select an analyzer
mine the applicability of regulatory limitations prior to use.
appropriate for that classification.
1.9 This international standard was developed in accor-
1.4 Test MethodsD287, D1298, and D6822are used in field
dance with internationally recognized principles on standard-
applications. This test method provides an alternative field
ization established in the Decision on Principles for the
method that is easily calibrated and does not pose the hazard of
Development of International Standards, Guides and Recom-
hydrometer glass breakage present in current field methods.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.5 Portable digital density meters measure the density and
temperature of the filled-in sample at the sample temperature.
2. Referenced Documents
The measured density and temperature are automatically con-
verted into:
2.1 ASTM Standards:
Density at 15 °C / density at 60 °F
D287 Test Method for API Gravity of Crude Petroleum and
Relative density 15 °C⁄15 °C / relative density 60 °F⁄60 °F
Petroleum Products (Hydrometer Method)
API gravity 15 °C / API gravity 60 °F
D1193 Specification for Reagent Water
D1250 Guide for Use of the Petroleum Measurement Tables
D1298 Test Method for Density, Relative Density, or API
1 Gravity of Crude Petroleum and Liquid Petroleum Prod-
This test method is under the jurisdiction of ASTM Committee D02 on
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of ucts by Hydrometer Method
Subcommittee D02.04.0D on Physical and Chemical Methods.
D4052 Test Method for Density, Relative Density, and API
Current edition approved Oct. 1, 2018. Published November 2018. Originally
approved in 2012. Last previous edition approved in 2013 as D7777 – 13.
DOI:10.1520/D7777-13R18E01.
This standard has been developed through the cooperative effort betweenASTM For referenced ASTM standards, visit the ASTM website, www.astm.org, or
International and the Energy Institute, London. The EI and ASTM International contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
logos imply that the ASTM International and EI standards are technically Standards volume information, refer to the standard’s Document Summary page on
equivalent, but does not imply that both standards are editorially identical. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7777 − 13 (2018)
Gravity of Liquids by Digital Density Meter ture. If the density meter does not have in-built software to
D4057 Practice for Manual Sampling of Petroleum and calculate the density at the reference temperature, this is
Petroleum Products calculated from the observed density at test temperature using
D4177 Practice for Automatic Sampling of Petroleum and the Petroleum Measurement Tables. The apparatus’ system is
Petroleum Products regularly checked using reagent grade water.
D6822 Test Method for Density, Relative Density, and API
Gravity of Crude Petroleum and Liquid Petroleum Prod- 5. Significance and Use
ucts by Thermohydrometer Method
5.1 The density, relative density, or API gravity of petro-
2.2 Energy Institute Standards:
leum products are important quality indicators and are used in
IP 475 Petroleum Liquids – Manual Sampling
quantity calculations or to satisfy application, transportation,
2.3 ASTM Adjuncts:
storage, and regulatory requirements.
Adjunct to D1250-04 Temperature and Pressure Volume
5.2 This test method should not be used to determine
Correction Factors for Generalized Crude Oils, Refined
density for custody transfer quantity calculations, particularly
Products, and Lubricating Oils
where mass or weight is the unit of quantity measurement.Test
Method D4052 is appropriate for these applications.
3. Terminology
3.1 Definitions:
6. Apparatus
3.1.1 adjustment, n—operation of bringing the portable
6.1 Portable Digital Density Meter—Capable, once
digital density meter to a state of performance suitable for its
calibrated, of determining density with an accuracy of
use, by setting or adjusting the instrument constants.
61kg⁄m , fitted with a temperature sensing device capable of
3.1.2 API gravity, n—special function of relative density
measuring temperatures to 60.5 °C, a pump mechanism for
(specific gravity) SG60° F⁄60 °F, represented by:
filling and emptying the U-tube and a digital display of the
°API 5 141.5/ SG60 °F/60 °F 2 131.5
~ !
results. Some density meters have in-built software for calcu-
3.1.2.1 Discussion—Relative density SG15 °C⁄15 °C is also
lating the density at 15 °C from the observed density at test
applied.
temperature. Some density meters have a mechanism for
3.1.3 calibration, n—operation that establishes the relation- adjusting the meter during calibration; for others, this adjust-
ment is carried out using the in-built software.
ship between the reference density of standards and the
corresponding reading of the instrument.
NOTE 1—The meter may also have a memory for storing results, or a
facility for connecting the meter to either a printer or a computer, or both.
3.1.3.1 validation, n—operation of checking the calibration
of the portable digital density meter at a single point close to
6.1.1 If the meter has in-built software it shall have been
the required operating point.
type tested to ensure that its firmware duplicates the Petroleum
3.1.4 density, n—mass per unit volume at a given tempera- Measurement Tables over the working temperatures and den-
sity ranges of the test method.
ture.
3.1.4.1 Discussion—Standard units of density are kg/m (SI 6.1.2 If the meter is to be used in an environment where a
risk assessment has identified that a flammable atmosphere is
unit) or mg/cm . Less preferred units, for example, kg/L or
g/mL, are still in use. likely to be present, the use of a portable digital density meter
with proper safety rating for the zone the instrument is being
3.1.5 relative density (specific gravity), n—ratio of the mass
operated in and the gas group that is being handled is
of a given volume of a liquid at a temperature t to the mass of
mandatory.
an equal volume of pure water at a temperature t . Both
6.1.3 The instrument shall be capable of converting the
temperatures shall be explicitly stated.
measured density and temperature into:
3.1.5.1 Discussion—The unit SG has no dimension. Com-
Density at 15 °C / density at 60 °F
mon reference temperatures include 15 °C⁄15 °C, 60 °F⁄60 °F,
Relative density 15 °C⁄15 °C / relative density 60 °F⁄60 °F
20 °C⁄20 °C, and 20 °C⁄4 °C.
API gravity 15 °C / API gravity 60 °F
according to Guide D1298. The instrument shall be capable
4. Summary of Test Method
of meeting the precision requirements described in this test
4.1 The test sample is brought to a temperature close to that
method.
of the density meter. If present, the density meter’s software
6.2 Source of Low-Pressure Air—For drying the U-tube.
program for calculating the density at the reference tempera-
ture is selected, and the oscillating U-tube of the density meter
NOTE2—Anaquariumairpumpfittedwithatubefilledwithadesiccant
is filled with the test portion in accordance with the manufac-
has been found to be suitable.
turer’s instructions. After stabilizing, the density meter’s in-
6.3 Density Meter Stand—(Optional).
built software calculates the density at the reference tempera-
6.4 Syringe—Glass or plastic (see Note 3), approximately
10 mL capacity with a Luer fitting (optional).
Available from Energy Institute, 61 New Cavendish St., London, WIG 7AR,
NOTE 3—Many plastic syringes designed for medical use are supplied
U.K., http://www.energyinst.org.
Available from ASTM International Headquarters. Order Adjunct No. with a coating of lubricant in the barrel. Some of these coatings can
ADJD1250CD or ADJD1250CS. Original adjunct produced in 2004. dissolve in the test portion samples altering the sample density. It is
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D7777 − 13 (2018)
therefore recommended that only syringes specified as non-lubricated
rinsing with proper solvent. The rinsing solvent has to be
should be used.
selected according to its ability to dissolve residues of the
measured sample. If the solvent used to remove sample
7. Reagents and Materials
residues is not volatile by itself, the use of a volatile second
7.1 Water—Conforming to Specification D1193, Type III.
solvent to remove residues of the first solvent is recommended.
7.2 Cleaning Solvent—General purpose reagent grade, for Follow the manufacturer’s instructions for further cleaning
cleaning the U-tube. requirements.
NOTE 4—Heptane or 40-60 Petroleum Spirit have been found to be
9. Calibration and Adjustment of the Instrument
suitable.
9.1 At least once every 12 months, verify the correct
7.3 Propan-2-ol—General purpose reagent for cleaning the
functioning of the meter using a Certified Reference Material
U-tube.
(CRM) (see 7.4 and Note 5).
7.4 Certified Reference Material (CRM)—With a density
NOTE 6—It is recommended that this apparatus verification is carried
approximating to the material under test, whose expansivity is
out either by the manufacturer or a qualified third party laboratory
in accordance with the Petroleum Measurement Tables (see
specializing in the measurement of density.
Note 5).
9.2 Check that the U-tube is clean and dry and if necessary
NOTE 5—While single compound hydrocarbons such as dodecane are
clean and dry in accordance with the recommended cleaning
suitable, it has been found that their expansivity is not described well by
procedure given in Appendix X1.
either the Petroleum Measurement Table 54 or ADJD1250CD ), and a
9.3 Clean the outside of the filling tube with cleaning
correction has to be applied. See Table A1.2 on predicted densities at
various temperatures for dodecane.
solvent and wipe dry.
9.4 Bring the CRM and the density meter to thermal
8. Sampling
equilibrium.
8.1 Use only representative samples obtained as described
9.5 Meters with In-Built Software:
in the Practices D4057, D4177, or IP 475 unless otherwise
9.5.1 Select the density at reference temperature program in
specified for test specimens and test units. The sampling
accordance with the manufacturer’s instructions.
procedure for the calibration or adjustment of the apparatus, or
both, and for testing is as follows: 9.5.2 Fill the U-tube with the CRM and check that there are
no air bubbles present. If there are bubbles, empty and refill.
8.1.1 Make sure that the portable digital density meter is in
thermal equilibrium with the ambient temperature. If the Allow the meter to stabilize. Record the density of the CRM.
If the CRM is a single compound hydrocarbon, apply a
instrument has been transferred from a much warmer or much
colder place immediately before use, wait for several minutes correction to the result, see Note 5 and Table A1.2. The result
obtained shall be equal to or less than R/1.414 from the
before measuring. Do not transfer the instrument frequently
between places with very different ambient temperatures, as certified value of the CRM, where R is the reproducibility of
this test method.
humidity condensations may cause measuring errors.
8.1.2 Make sure to have the samples at or above ambient 9.5.3 If the value obtained does not meet these criteria,
clean the U-tube and reverify using the CRM. If the value
temperature. Do not fill samples which are much colder
(5 °C⁄9 °F) than the ambient temperature. This may generate obtained still fails to meet this criteria, either carry out a
recalibration following the manufacturer’s instructions or re-
humidity condensation on the oscillating U-tube sensor, caus-
turn the meter to the manufacturer for servicing and adjust-
ing incorrect measurements and potentially harming the instru-
ment.
ment.
8.1.3 Follow the manufacturer’s instructions for filling
9.6 Meters without In-Built Software:
samples into the instrument. If the sampling system of the
9.6.1 Fill the U-tube with the CRM and check that there are
portable density meter is not completely free of liquid, drain it
no air bubbles present. If there are bubbles, empty and refill.
first as much as possible. Then fill a first portion of the sample
Allow the meter to stabilize. Record the density of the CRM
and drain it im
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