ASTM D1657-12(2017)
(Test Method)Standard Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Hydrometer
Standard Test Method for Density or Relative Density of Light Hydrocarbons by Pressure Hydrometer
SIGNIFICANCE AND USE
5.1 The density or relative density of light hydrocarbons and liquefied petroleum gases is used in custody transfer quantity calculations or to satisfy transportation, storage, and regulatory requirements.
SCOPE
1.1 This test method covers the determination of the density or relative density of light hydrocarbons including liquefied petroleum gases (LPG) having Reid vapor pressures exceeding 101.325 kPa (14.696 psi).
1.2 The prescribed apparatus should not be used for materials having vapor pressures higher than 1.4 MPa (200 psi) at the test temperature. This pressure limit is dictated by the type of equipment. Higher pressures can apply to other equipment designs.
1.3 The initial pressure hydrometer readings obtained are uncorrected hydrometer readings and not density measurements. Readings are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are corrected for the meniscus effect, the thermal glass expansion effect, alternate calibration temperature effects and to the reference temperature by means of calculations and Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable.
1.4 Values determined as density or relative density can be converted to equivalent values in the other units or alternative reference temperatures by means of Interconversion Procedures API MPMS Chapter 11.5, or Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable.
1.5 The calculations required in Section 11 shall be applied to the initial pressure hydrometer reading with observations and results reported as required by Section 11 prior to use in a subsequent calculation procedure (measurement ticket calculation, meter factor calculation, or base prover volume determination).
1.6 Annex A1 contains a procedure for verifying or certifying the equipment for this test method.
1.7 The values in SI units are to be regarded as the standard. US Customary values shown in adjacent parentheses are for information only and may not be exactly equivalent. Both SI and customary units have been rounded so that 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 and health 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
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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: D1657 − 12 (Reapproved 2017)
Manual of Petroleum Measurement Standards (MPMS), Chapter 9.2
Standard Test Method for
Density or Relative Density of Light Hydrocarbons by
Pressure Hydrometer
This standard is issued under the fixed designation D1657; 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.
1. Scope and results reported as required by Section 11 prior to use in a
subsequent calculation procedure (measurement ticket
1.1 This test method covers the determination of the density
calculation, meter factor calculation, or base prover volume
or relative density of light hydrocarbons including liquefied
determination).
petroleum gases (LPG) having Reid vapor pressures exceeding
101.325 kPa (14.696 psi). 1.6 AnnexA1 contains a procedure for verifying or certify-
ing the equipment for this test method.
1.2 The prescribed apparatus should not be used for mate-
rials having vapor pressures higher than 1.4 MPa (200 psi) at 1.7 The values in SI units are to be regarded as the standard.
the test temperature. This pressure limit is dictated by the type US Customary values shown in adjacent parentheses are for
of equipment. Higher pressures can apply to other equipment information only and may not be exactly equivalent. Both SI
designs. andcustomaryunitshavebeenroundedsothattheymaynotbe
exactly equivalent.
1.3 The initial pressure hydrometer readings obtained are
1.8 This standard does not purport to address all of the
uncorrected hydrometer readings and not density measure-
safety concerns, if any, associated with its use. It is the
ments. Readings are measured on a hydrometer at either the
responsibility of the user of this standard to establish appro-
reference temperature or at another convenient temperature,
priate safety and health practices and determine the applica-
and readings are corrected for the meniscus effect, the thermal
bility of regulatory limitations prior to use.
glass expansion effect, alternate calibration temperature effects
1.9 This international standard was developed in accor-
and to the reference temperature by means of calculations and
dance with internationally recognized principles on standard-
Adjunct to D1250 Guide for Petroleum Measurement Tables
ization established in the Decision on Principles for the
(API MPMS Chapter 11.1) orAPI MPMS Chapter 11.2.4 (GPA
Development of International Standards, Guides and Recom-
TP-27), as applicable.
mendations issued by the World Trade Organization Technical
1.4 Values determined as density or relative density can be
Barriers to Trade (TBT) Committee.
converted to equivalent values in the other units or alternative
reference temperatures by means of Interconversion Proce-
2. Referenced Documents
duresAPI MPMS Chapter 11.5, orAdjunct to D1250 Guide for
2.1 ASTM Standards:
Petroleum Measurement Tables (API MPMS Chapter 11.1) or
D1250 Guide for Use of the Petroleum Measurement Tables
API MPMS Chapter 11.2.4 (GPA TP-27), as applicable.
D1265 Practice for Sampling Liquefied Petroleum (LP)
1.5 The calculations required in Section 11 shall be applied
Gases, Manual Method
to the initial pressure hydrometer reading with observations
D1298 Test Method for Density, Relative Density, and API
Gravity of Crude Petroleum and Liquid Petroleum Prod-
This test method is under the jurisdiction of ASTM Committee D02 on
ucts by Hydrometer Method (API MPMS Chapter 9.1)
Petroleum Products, Liquid Fuels, and Lubricants and the API Committee on
E1 Specification for ASTM Liquid-in-Glass Thermometers
Petroleum Measurement, and is the direct responsibility of Subcommittee D02.02
/COMQ, the joint ASTM-API Committee on Hydrocarbon Measurement for
Custody Transfer (Joint ASTM-API). This test method has been approved by the
sponsoring committees and accepted by the Cooperating Societies in accordance
with established procedures. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 15, 2017. Published July 2017. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1939. Last previous edition approved in 2012 as D1657 – 12. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/D1657-12R17. the ASTM website.
© Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
D1657 − 12 (2017)
E100 Specification for ASTM Hydrometers pressure cylinder is filled to a level at which the enclosed
2.2 API Standards: hydrometer floats freely, and the cylinder is then placed in a
MPMS Chapter 9.1 Test Method for Density, Relative constant-temperature bath (if needed). When the temperature
Density, and API Gravity of Crude Petroleum and Liquid has reached equilibrium, the hydrometer reading and the
Petroleum Products by Hydrometer Method (ASTM Test temperature of the sample are read. The observed hydrometer
Method D1298) reading is corrected for the meniscus effect, alternate calibra-
MPMS Chapter 11.1 Temperature and Pressure Volume Cor- tion temperature effects and reduced to the reference tempera-
rection Factors for Generalized Crude Oils, Refined Prod- ture by means of the volume correction factors or tables as
ucts and Lubricating Oils (Adjunct to ASTM D1250) applicable by use of the appropriate Adjunct to D1250 Guide
MPMS Chapter 11.2.2 Compressibility Factors for Hydro- for Petroleum Measurement Tables (API MPMS Chapter 11.1)
carbons: 0.350-0.0637 Relative Density (60°F/60°F) and orAPI MPMS Chapter 11.2.4 (GPATP-27), as applicable, and
-50°F to 140°F Metering Temperature observed temperature from the thermometer.
MPMS Chapter 11.2.2M Compressibility Factors for Hydro-
5. Significance and Use
carbons: 350-637 Kilograms per Cubic Meter Density
15°C and -46°C to 60°C Metering Temperatures
5.1 Thedensityorrelativedensityoflighthydrocarbonsand
MPMSChapter 11.2.4 Temperature Correction for the Vol-
liquefied petroleum gases is used in custody transfer quantity
ume of NGL and LPG Tables 23E, 24E, 53E, 54E, 59E
calculations or to satisfy transportation, storage, and regulatory
and 60E (joint standard with GPA TP-27)
requirements.
MPMS Chapter 11.5 Density/Weight/Volume Intraconver-
sion
6. Apparatus
2.3 GPA Standards:
6.1 Hydrometers, graduated in density with a range from
GPA Technical Publication TP-27 Temperature Correction
3 3
500 kg⁄m to 650 kg⁄m , or in relative density with a range
for the Volume of NGL and LPG, Tables 23E, 24E, 53E,
from 0.500 to 0.650, and conforming to the dimensions in
54E, 59E and 60E (joint standard with API MPMS
Specification E100.
Chapter 11.2.4)
6.1.1 Thermohydrometers, for field applications, thermohy-
2.4 ASTM Adjuncts:
drometers may be more convenient than hydrometers with
AdjuncttoD1250GuideforPetroleumMeasurementTables
separate thermometers. They shall conform to Specification
(API MPMS Chapter 11.1)
E100, Thermohydrometer Nos. 101H or 310H.
6.1.1.1 Thermohydrometers shall be of suitable range and
3. Terminology
have dimensions to float freely within the pressure hydrometer
3.1 Definitions:
cylinder with clearances of 5 mm at the wall and 25 mm at the
3.1.1 density, n—themassofliquidperunitvolumeat15 °C
top and bottom.
and its saturation pressure with the standard unit of measure-
6.1.1.2 The test report shall state that a thermohydrometer
ment being kilograms per cubic metre.
was used.
3.1.1.1 Discussion—Other reference temperatures, such as
6.1.1.3 The user should ascertain that the instruments used
20 °C may be used for some products or in some locations.
for this procedure conform to the requirements set out above
Less preferred units of measurement; for example, kg/L or
with respect to materials, dimensions, and scale errors. In cases
g/mL, are still in use.
where the instrument is provided with a calibration certificate
3.1.2 relative density (specific gravity), n—the ratio of the
issued by a recognized standardizing body, the instrument is
mass of a given volume of liquid at a specific temperature to
classed as certified and the appropriate corrections for the
the mass of an equal volume of pure water at the same or
meniscus effect, the thermal glass expansion effect, and alter-
different temperature. Both reference temperatures shall be
native calibration temperature effects shall be applied to the
explicitly stated.
observed readings prior to corrections. Instruments that satisfy
3.1.2.1 Discussion—Common reference temperatures in-
the requirements of this test method, but are not provided with
clude 60/60 °F, 20⁄20 °C, 20/4 °C. The historic deprecated
a recognized calibration certificate, are classed as uncertified
term “specific gravity” may still be found.
and the appropriate corrections for the meniscus effect, the
thermal glass expansion effect, and alternative calibration
3.1.3 thermohydrometer, n—a glass hydrometer with a self-
temperature effects shall be applied to the observed readings
contained mercury thermometer.
prior to corrections.
4. Summary of Test Method
6.2 Hydrometer Cylinder, constructed of transparent plastic;
4.1 The apparatus is purged with a portion of the sample
for example, poly(methyl methacrylate) or equivalent material,
before filling with the portion to be used for testing. The
conforming to the design and recommended dimensions given
in Fig. 1. The cylinder shall be of such dimensions that the
hydrometer shall float freely within it.The ends shall be tightly
Available from American Petroleum Institute (API), 1220 L. St., NW,
Washington, DC 20005-4070, http://www.api.org.
sealed with neoprene gaskets and metal end plates as shown in
Available from Gas ProcessorsAssociation (GPA), 6526 E. 60th St., Tulsa, OK
Fig. 1.(Warning—A protective shield shall be placed around
74145, http://www.gpaglobal.org.
the cylinder. Replace any cylinders that show signs of fogging,
Available from ASTM International Headquarters. Order Adjunct No.
ADJD1250. Original adjunct produced in 1983. crazing, cracking, or etching.)
D1657 − 12 (2017)
FIG. 1 Pressure Hydrometer Cylinder
NOTE 1—Certain compounds attack plastics and cloud the inner surface however, to clean the cylinder thoroughly after each determination.
of the cylinder, making it difficult or impossible to read the hydrometer. Ketones and alcohols should not be used for cleaning as they attack and
Tests showed no attack by ethane, ethene (ethylene), propane, propylene, weaken plastics while aromatics also tend to attack the surface of plastics
butane, methylpropane (isobutane), butenes (normal butylenes), methyl- and should similarly not be used. A light aliphatic hydrocarbon is
propene (isobutylene), pentane, and methylbutane (isopentane), and no recommended for cleaning. (Warning—Extremely flammable. Harmful if
attack is expected from butadiene and acetaldehyde. Users are cautioned, inhaled. Vapors may cause flash fire.)
D1657 − 12 (2017)
6.2.1 The liquid inlet valve and the liquid outlet valve shall pressure in the cylinder be allowed to rise above a gage
be tightly connected to a base plate that shall be bored to give pressure of 1.4 MPa (200 psi).
both valves a common inlet to the cylinder. The vapor vent 8.1.3 When the cylinder has been filled, close the inlet valve
valve shall be similarly connected to the top plate, which shall and open the outlet and vent valves, permitting the contents of
be bored to provide a vapor outlet from the pressure cylinder. the cylinder to be withdrawn completely and the pressure
All valves shall be 6 mm ( ⁄4 in.) or equivalent needle valves. inside the cylinder to be returned to atmospheric pressure.
8.1.4 Close the outlet and vent valves and open the inlet
6.2.2 The cylinder shall not be operated at a gage pressure
greater than 1.4 MPa (200 psi). A hydrostatic test at 2.8 MPa valve, filling the cylinder to a level at which the enclosed
hydrometer floats freely. If it is necessary to accomplish this
(400 psi) shall be carried out at intervals no greater than
12 months. filling by venting vapor through the vent valve, repeat the
purging to cool the cylinder sufficiently to permit its being
NOTE 2—For Safety—The cylinder should be equipped with appropri-
filled without venting.
ate safety devices to prevent over-pressure. Consideration should be given
8.1.5 With all valves closed, examine the apparatus for
to pressure testing the cylinder at 1.25 to 1.5 times its normal maximum
operating pressure on a periodic basis, not to exceed two years. leaks. If leaks are detected, discard the sample, reduce the
pressure to atmospheric and repair the leaks. Repeat the
6.3 Thermometers, conforming to ASTM 12C or 12F in
sampling procedure.
Specification E1. The thermometer shall be held firmly inside
the hydrometer cylinder by a clip in such a manner that it does
9. Verification of Apparatus
not interfere with the free movement of the hydrometer.
9.1 Carefully clean and dry the hydrometer and the inside
6.4 Constant-Temperature Bath, of dimensions such that it
wall of the pressure cylinder.
canaccommodatethehydrometercylinderwiththetestportion
9.2 Insert the hydrometer in the pressure cylinder and attach
fully immersed below the test portion liquid surface, and a
the thermometer and cover plate. Connect the source of supply
temperature control system capable of maintaining the bath
of the reference liquid to the inlet valve and ascertain that the
temperature within 0.25 °C of the test temperature throughout
connections are free of leaks. Fill the hydrometer with one of
the duration of the test.
the reference fluids (see Section 7) by the procedure given in
8.1.2 – 8.1.5.
7. Reference Liquids
9.3 Disconnect the hydrometer cylinder from the source of
7.1 The following reference liquids are required for stan-
supply of liquid and place it in the constant-temperature bath
dardization of the hydrometer:
maintained within 0.2 °C of the test temperature until thermal
7.1.1 Propane, pure grade, having a nominal density of
equilibrium has been obtained. To accelerate thermal
507.6 kg⁄m at 15 °C or a relative density 60/60 °F of 0.50699.
adjustment, occasionally remove the hydrometer cylinder from
(Warning—Extremely flammable. Harmful if inhaled. Vapors
the constant-temperature bath, tilt to a horizontal position, rock
may cause flash fire.) The density of the reference liquid used
gently a few times to ensure mixing, and r
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
´1
Designation: D1657 − 12 D1657 − 12 (Reapproved 2017)
Manual of Petroleum Measurement Standards (MPMS), Chapter 9.2
Standard Test Method for
Density or Relative Density of Light Hydrocarbons by
Pressure Hydrometer
This standard is issued under the fixed designation D1657; 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—Corrected API MPMS naming convention throughout editorially in October 2012.
1. Scope*Scope
1.1 This test method covers the determination of the density or relative density of light hydrocarbons including liquefied
petroleum gases (LPG) having Reid vapor pressures exceeding 101.325 kPa (14.696 psi).101.325 kPa (14.696 psi).
1.2 The prescribed apparatus should not be used for materials having vapor pressures higher than 1.4 MPa (200 psi) 1.4 MPa
(200 psi) at the test temperature. This pressure limit is dictated by the type of equipment. Higher pressures can apply to other
equipment designs.
1.3 The initial pressure hydrometer readings obtained are uncorrected hydrometer readings and not density measurements.
Readings are measured on a hydrometer at either the reference temperature or at another convenient temperature, and readings are
corrected for the meniscus effect, the thermal glass expansion effect, alternate calibration temperature effects and to the reference
temperature by means of calculations and Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1)
or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable.
1.4 Values determined as density or relative density can be converted to equivalent values in the other units or alternative
reference temperatures by means of Interconversion Procedures API MPMS Chapter 11.5, or Adjunct to D1250 Guide for
Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as applicable.
1.5 The calculations required in Section 11 shall be applied to the initial pressure hydrometer reading with observations and
results reported as required by Section 11 prior to use in a subsequent calculation procedure (measurement ticket calculation, meter
factor calculation, or base prover volume determination).
1.6 Annex A1 contains a procedure for verifying or certifying the equipment for this test method.
1.7 The values in SI units are to be regarded as the standard. US Customary values shown in adjacent parentheses are for
information only and may not be exactly equivalent. Both SI and customary units have been rounded so that 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 and health 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.
2. Referenced Documents
2.1 ASTM Standards:
D1250 Guide for Use of the Petroleum Measurement Tables
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and the API Committee on Petroleum
Measurement, and is the direct responsibility of Subcommittee D02.02 /COMQ, the joint ASTM-API Committee on Hydrocarbon Measurement for Custody Transfer (Joint
ASTM-API). This test method has been approved by the sponsoring committees and accepted by the Cooperating Societies in accordance with established procedures.
Current edition approved June 1, 2012July 15, 2017. Published August 2012July 2017. Originally approved in 1939. Last previous edition approved in 20072012 as
D1657–02(2007).D1657 – 12. DOI: 10.1520/D1657-12E01.10.1520/D1657-12R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
© Jointly copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, USA and the American Petroleum Institute (API), 1220 L Street NW, Washington DC 20005, USA
D1657 − 12 (2017)
D1265 Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method
D1298 Test Method for Density, Relative Density, and API Gravity of Crude Petroleum and Liquid Petroleum Products by
Hydrometer Method (API MPMS Chapter 9.1)
E1 Specification for ASTM Liquid-in-Glass Thermometers
E100 Specification for ASTM Hydrometers
2.2 API Standards:
MPMS Chapter 9.1 Test Method for Density, Relative Density, and API Gravity of Crude Petroleum and Liquid Petroleum
Products by Hydrometer Method (ASTM Test Method D1298)
MPMS Chapter 11.1 Temperature and Pressure Volume Correction Factors for Generalized Crude Oils, Refined Products and
Lubricating Oils (Adjunct to ASTM D1250)
MPMS Chapter 11.2.2 Compressibility Factors for Hydrocarbons: 0.350-0.0637 Relative Density (60°F/60°F) and -50°F to
140°F Metering Temperature
MPMS Chapter 11.2.2M Compressibility Factors for Hydrocarbons: 350-637 Kilograms per Cubic Meter Density 15°C and
-46°C to 60°C Metering Temperatures
MPMSChapter 11.2.4 Temperature Correction for the Volume of NGL and LPG Tables 23E, 24E, 53E, 54E, 59E and 60E (joint
standard with GPA TP-27)
MPMS Chapter 11.5 Density/Weight/Volume Intraconversion
2.3 GPA Standards:
GPA Technical Publication TP-27 Temperature Correction for the Volume of NGL and LPG, Tables 23E, 24E, 53E, 54E, 59E
and 60E (joint standard with API MPMS Chapter 11.2.4)
2.4 ASTM Adjuncts:
Adjunct to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1)
3. Terminology
3.1 Definitions:
3.1.1 density, n—the mass of liquid per unit volume at 15°C15 °C and its saturation pressure with the standard unit of
measurement being kilograms per cubic metre.
Available from American Petroleum Institute (API), 1220 L. St., NW, Washington, DC 20005-4070, http://www.api.org.
Available from Gas Processors Association (GPA), 6526 E. 60th St., Tulsa, OK 74145, http://www.gpaglobal.org.
Available from ASTM International Headquarters. Order Adjunct No. ADJD1250. Original adjunct produced in 1983.
3.1.1.1 Discussion—
Other reference temperatures, such as 20°C20 °C may be used for some products or in some locations. Less preferred units of
measurement; for example, kg/L or g/mL, are still in use.
3.1.2 relative density (specific gravity), n—the ratio of the mass of a given volume of liquid at a specific temperature to the mass
of an equal volume of pure water at the same or different temperature. Both reference temperatures shall be explicitly stated.
3.1.2.1 Discussion—
Common reference temperatures include 60/60°F, 20/20°C,60/60 °F, 20 20/4°C.⁄20 °C, 20/4 °C. The historic deprecated term
“specific gravity” may still be found.
3.1.3 thermohydrometer, n—a glass hydrometer with a self-contained mercury thermometer.
4. Summary of Test Method
4.1 The apparatus is purged with a portion of the sample before filling with the portion to be used for testing. The pressure
cylinder is filled to a level at which the enclosed hydrometer floats freely, and the cylinder is then placed in a constant-temperature
bath (if needed). When the temperature has reached equilibrium, the hydrometer reading and the temperature of the sample are
read. The observed hydrometer reading is corrected for the meniscus effect, alternate calibration temperature effects and reduced
to the reference temperature by means of the volume correction factors or tables as applicable by use of the appropriate Adjunct
to D1250 Guide for Petroleum Measurement Tables (API MPMS Chapter 11.1) or API MPMS Chapter 11.2.4 (GPA TP-27), as
applicable, and observed temperature from the thermometer.
5. Significance and Use
5.1 The density or relative density of light hydrocarbons and liquefied petroleum gases is used in custody transfer quantity
calculations or to satisfy transportation, storage, and regulatory requirements.
D1657 − 12 (2017)
6. Apparatus
3 3
6.1 Hydrometers, graduated in density with a range from 500500 kg ⁄m to 650 650 kg kg/m⁄m , or in relative density with a
range from 0.500 to 0.650, and conforming to the dimensions in Specification E100.
6.1.1 Thermohydrometers, for field applications, thermohydrometers may be more convenient than hydrometers with separate
thermometers. They shall conform to Specification E100, Thermohydrometer Nos. 101H or 310H.
6.1.1.1 Thermohydrometers shall be of suitable range and have dimensions to float freely within the pressure hydrometer
cylinder with clearances of 5 mm 5 mm at the wall and 25 mm 25 mm at the top and bottom.
6.1.1.2 The test report shall state that a thermohydrometer was used.
6.1.1.3 The user should ascertain that the instruments used for this procedure conform to the requirements set out above with
respect to materials, dimensions, and scale errors. In cases where the instrument is provided with a calibration certificate issued
by a recognized standardizing body, the instrument is classed as certified and the appropriate corrections for the meniscus effect,
the thermal glass expansion effect, and alternative calibration temperature effects shall be applied to the observed readings prior
to corrections. Instruments that satisfy the requirements of this test method, but are not provided with a recognized calibration
certificate, are classed as uncertified and the appropriate corrections for the meniscus effect, the thermal glass expansion effect, and
alternative calibration temperature effects shall be applied to the observed readings prior to corrections.
6.2 Hydrometer Cylinder, constructed of transparent plastic; for example, poly(methyl methacrylate) or equivalent material,
conforming to the design and recommended dimensions given in Fig. 1. The cylinder shall be of such dimensions that the
hydrometer shall float freely within it. The ends shall be tightly sealed with neoprene gaskets and metal end plates as shown in
Fig. 1. (Warning—A protective shield shall be placed around the cylinder. Replace any cylinders that show signs of fogging,
crazing, cracking, or etching.)
NOTE 1—Certain compounds attack plastics and cloud the inner surface of the cylinder, making it difficult or impossible to read the hydrometer. Tests
showed no attack by ethane, ethene (ethylene), propane, propylene, butane, methylpropane (isobutane), butenes (normal butylenes), methylpropene
(isobutylene), pentane, and methylbutane (isopentane), and no attack is expected from butadiene and acetaldehyde. Users are cautioned, however, to clean
the cylinder thoroughly after each determination. Ketones and alcohols should not be used for cleaning as they attack and weaken plastics while aromatics
also tend to attack the surface of plastics and should similarly not be used. A light aliphatic hydrocarbon is recommended for cleaning.
(Warning—Extremely flammable. Harmful if inhaled. Vapors may cause flash fire.)
6.2.1 The liquid inlet valve and the liquid outlet valve shall be tightly connected to a base plate that shall be bored to give both
valves a common inlet to the cylinder. The vapor vent valve shall be similarly connected to the top plate, which shall be bored
to provide a vapor outlet from the pressure cylinder. All valves shall be 6 mm 6 mm ( ⁄4 in.) in.) or equivalent needle valves.
6.2.2 The cylinder shall not be operated at a gage pressure greater than 1.4 MPa (200 psi). 1.4 MPa (200 psi). A hydrostatic test
at 2.8 MPa (400 psi) 2.8 MPa (400 psi) shall be carried out at intervals no greater than 12 months.12 months.
NOTE 2—For Safety—The cylinder should be equipped with appropriate safety devices to prevent over-pressure. Consideration should be given to
pressure testing the cylinder at 1.25 to 1.5 times its normal maximum operating pressure on a periodic basis, not to exceed two years.
6.3 Thermometers, conforming to ASTM 12C or 12F in Specification E1. The thermometer shall be held firmly inside the
hydrometer cylinder by a clip in such a manner that it does not interfere with the free movement of the hydrometer.
6.4 Constant-Temperature Bath, of dimensions such that it can accommodate the hydrometer cylinder with the test portion fully
immersed below the test portion liquid surface, and a temperature control system capable of maintaining the bath temperature
within 0.25°C0.25 °C of the test temperature throughout the duration of the test.
7. Reference Liquids
7.1 The following reference liquids are required for standardization of the hydrometer:
7.1.1 Propane, pure grade, having a nominal density of 507.6 507.6 kg kg/m⁄m at 15°C15 °C or a relative density
60/60°F60/60 °F of 0.50699. (Warning—Extremely flammable. Harmful if inhaled. Vapors may cause flash fire.) The density of
the reference liquid used shall be known.
7.1.2 Butane, pure grade, having a nominal density of 584.1 kg ⁄m at 15°C15 °C or a relative density 60/60°F60/60 °F of
0.5840. (Warning—Extremely flammable. Harmful if inhaled. Vapors may cause flash fire.) The density of the reference liquid
used shall be known.
8. Sampling
8.1 Unless otherwise specified, samples of liquid hydrocarbons shall be obtained by the procedures described in Practice D1265.
The procedure for sampling for verification of the apparatus and for subsequent testing is described as follows.
8.1.1 Connect the source of supply of the liquid to be tested to the inlet valve by suitable fittings so that a representative sample
can be introduced into the cylinder. Ascertain that these connections are free of leaks. Open the outlet and vent valves and purge
the sampling connections by opening the inlet valve slightly, permitting the product to flow through the outlet valve at the bottom
of the cylinder and the vent valve at the top of the cylinder.
D1657 − 12 (2017)
FIG. 1 Pressure Hydrometer Cylinder
8.1.2
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