ASTM D1267-23

Standard Test Method for Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method)

SIGNIFICANCE AND USE
5.1 Information on the vapor pressures of liquefied petroleum gas products under temperature conditions from 37.8 °C to 70 °C (100 °F to 158 °F) is pertinent to selection of properly designed storage vessels, shipping containers, and customer utilization equipment to ensure safe handling of these products.  
5.2 Determination of the vapor pressure of liquefied petroleum gas is important for safety reasons to ensure that the maximum operating design pressures of storage, handling, and fuel systems will not be exceeded under normal operating temperature conditions.  
5.3 For liquefied petroleum gases, vapor pressure can be considered a semi-quantitative measure of the amount of the most volatile material present in the product, and this can give an indication of low temperature operability.
SCOPE
1.1 This test method covers the determination of the gauge vapor pressures of liquefied petroleum gas products at temperatures of 37.8 °C (100 °F) up to and including a test temperature of 70 °C (158 °F). (Warning—Extremely flammable gas. May be harmful when inhaled.)
Note 1: An alternative method for measurement of vapor pressure of liquefied petroleum gases is Test Method D6897.  
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.3 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. For specific warning statements, see 1.1 and Annex A2.  
1.4 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

• Status: Published
• Publication Date: 28-Feb-2023
• ICS: 75.160.30 - Gaseous fuels
• Technical Committee: D02 - Petroleum Products, Liquid Fuels, and Lubricants
• Drafting Committee: D02.H0 - Liquefied Petroleum Gas

Relations

• Refers: ASTM D4175-23a - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 15-Dec-2023
• Refers: ASTM D1265-23a - Standard Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method
• Effective Date: 01-Dec-2023
• Refers: ASTM D4175-23e1 - Standard Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
• Effective Date: 01-Jul-2023
• Refers: ASTM D323-15 - Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)
• Effective Date: 01-Apr-2015
• Refers: ASTM D323-06 - Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)
• Effective Date: 01-Aug-2006
• Refers: ASTM D1265-04a - Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)
• Effective Date: 01-Nov-2004
• Refers: ASTM D1265-04 - Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)
• Effective Date: 01-May-2004
• Refers: ASTM D6897-03a - Standard Test Method for Vapor Pressure of Liquefied Petroleum Gases (LPG) (Expansion Method)
• Effective Date: 01-Dec-2003
• Refers: ASTM D6897-03 - Standard Test Method for Vapor Pressure of Liquefied Petroleum Gases (LPG) (Expansion Method)
• Effective Date: 10-Mar-2003
• Refers: ASTM D323-99a - Standard Test Method for Vapor Pressure of Petroleum Products (Reid Method)
• Effective Date: 10-Apr-1999
• Refers: ASTM D1265-97 - Standard Practice for Sampling Liquefied Petroleum (LP) Gases (Manual Method)
• Effective Date: 10-Nov-1997
• Referred By: ASTM D7901-23 - Standard Specification for Dimethyl Ether for Fuel Purposes
• Effective Date: 01-Mar-2023

Overview

ASTM D1267-23: Standard Test Method for Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases (LP-Gas Method) provides a reliable procedure for determining the gauge vapor pressure of liquefied petroleum gas (LPG) products at specific temperatures from 37.8 °C (100 °F) up to 70 °C (158 °F). Published by ASTM International, this method plays an essential role in ensuring the safety and quality of LPG products used in storage, transportation, and end-user equipment. By providing accurate vapor pressure data, ASTM D1267 helps stakeholders select appropriate storage vessels, shipping containers, and systems for safe handling and optimal performance of LP gases under various temperature conditions.

Key Topics

• Vapor Pressure Measurement: The standard describes a method for preparing LPG samples and using calibrated equipment to determine gauge vapor pressure at select temperatures. The method is essential for LPG with components such as propane, propylene, butanes, and butylenes.
• Safety Considerations: LP gases are extremely flammable and vapor can be hazardous if inhaled. The standard emphasizes safe sample handling, proper ventilation, and precautions against ignition sources.
• Equipment and Calibration: Precise guidelines are provided for using specific vapor pressure apparatus, including pressure gauges, water baths, and barometric pressure adjustments.
• Data Reporting: Results must be reported in appropriate SI units (kilopascals or pounds per square inch) and directly reference this standard for consistency and traceability.
• Quality Assurance: Regular verification of apparatus and adherence to procedures ensure test repeatability and reproducibility.

Applications

The ASTM D1267-23 test method is widely applicable within industries that manufacture, store, transport, or utilize liquefied petroleum gases. Key applications include:

• LPG Storage Design: Vapor pressure information determines the correct specification of storage tanks and pressure relief systems, reducing the risk of overpressure incidents.
• Shipping and Transport: Safe transfer and distribution of LPG rely on accurate pressure data to comply with safety standards and regulatory requirements.
• Equipment Selection: Suitable valves, regulators, and handling devices are chosen based on vapor pressure characteristics to ensure operability under different environmental conditions.
• Quality Control: Refineries, LPG distributors, and laboratories use this method to monitor product composition and guarantee compliance with commercial and safety specifications.
• Operational Safety: Understanding vapor pressure helps address hazards related to temperature fluctuations, preventing leaks and accidental releases.

Related Standards

ASTM D1267-23 references and aligns with several related standards, enhancing its relevance and applicability in the petroleum industry:

• ASTM D323: Test Method for Vapor Pressure of Petroleum Products (Reid Method); provides complementary techniques for different sample types.
• ASTM D1265: Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method; covers best practices for obtaining representative LPG samples.
• ASTM D4175: Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants; establishes key definitions used throughout the industry.
• ASTM D6897: Test Method for Vapor Pressure of Liquefied Petroleum Gases (Expansion Method); cited as an alternative approach for measuring LPG vapor pressure.
• International Principles: Developed in accordance with WTO guidelines on standardization to ensure global acceptance.

By adhering to ASTM D1267-23, organizations enhance safety, regulatory compliance, and product reliability within the liquefied petroleum gas sector.

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.
Designation: D1267 − 23
Standard Test Method for
Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases
(LP-Gas Method)
This standard is issued under the fixed designation D1267; 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* D6897 Test Method for Vapor Pressure of Liquefied Petro-
leum Gases (LPG) (Expansion Method)
1.1 This test method covers the determination of the gauge
vapor pressures of liquefied petroleum gas products at tem-
3. Terminology
peratures of 37.8 °C (100 °F) up to and including a test
temperature of 70 °C (158 °F). (Warning—Extremely flam- 3.1 Definitions:
mable gas. May be harmful when inhaled.) 3.1.1 For definitions of terms used in this test method, refer
to Terminology D4175.
NOTE 1—An alternative method for measurement of vapor pressure of
3.1.2 liquefied petroleum gas (LP gas, LPG), n—a narrow
liquefied petroleum gases is Test Method D6897.
boiling range mixture of hydrocarbons consisting of propane,
1.2 The values stated in SI units are to be regarded as
propylene, butanes, and butylenes, individually or in specified
standard. The values given in parentheses after SI units are
combinations, with limited amounts of other hydrocarbons
provided for information only and are not considered standard.
(such as ethane) and may contain naturally occurring,
1.3 This standard does not purport to address all of the
petroleum-derived non-hydrocarbons.
safety concerns, if any, associated with its use. It is the
3.1.3 vapor pressure, n—the pressure exerted by the vapor
responsibility of the user of this standard to establish appro-
of a liquid when in equilibrium with the liquid.
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
4. Summary of Test Method
For specific warning statements, see 1.1 and Annex A2.
4.1 The test apparatus, consisting of two interconnected
1.4 This international standard was developed in accor-
chambers and equipped with a suitable pressure gauge, is
dance with internationally recognized principles on standard-
purged with a portion of the sample which is then discarded.
ization established in the Decision on Principles for the
The apparatus is then filled completely with the portion of the
Development of International Standards, Guides and Recom-
sample to be tested. Thirty-three and one-third to forty volume
mendations issued by the World Trade Organization Technical
percent of the sample content of the apparatus is immediately
Barriers to Trade (TBT) Committee.
withdrawn to provide adequate free space for product expan-
2. Referenced Documents sion. The apparatus is then immersed in a water bath main-
2 tained at the standard test temperature of 37.8 °C (100 °F) or,
2.1 ASTM Standards:
optionally, at some higher test temperature up to and including
D323 Test Method for Vapor Pressure of Petroleum Products
a test temperature of 70 °C (158 °F).
(Reid Method)
D1265 Practice for Sampling Liquefied Petroleum (LP) 4.2 The observed gauge pressure at equilibrium, after cor-
Gases, Manual Method recting for gauge error and correcting to a standard barometric
D4175 Terminology Relating to Petroleum Products, Liquid pressure, is reported as the LPG Vapor Pressure at the selected
Fuels, and Lubricants test temperature.
5. Significance and Use
This test method is under the jurisdiction of ASTM Committee D02 on
5.1 Information on the vapor pressures of liquefied petro-
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.H0 on Liquefied Petroleum Gas.
leum gas products under temperature conditions from 37.8 °C
Current edition approved March 1, 2023. Published March 2023. Originally
to 70 °C (100 °F to 158 °F) is pertinent to selection of properly
approved in 1953. Last previous edition approved in 2018 as D1267 – 18. DOI:
designed storage vessels, shipping containers, and customer
10.1520/D1267-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or utilization equipment to ensure safe handling of these products.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
5.2 Determination of the vapor pressure of liquefied petro-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. leum gas is important for safety reasons to ensure that the
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1267 − 23
maximum operating design pressures of storage, handling, and 9. Procedure
fuel systems will not be exceeded under normal operating
9.1 Safe means for the disposal of vapors and liquids during
temperature conditions.
this operation and in the subsequent sampling operation shall
5.3 For liquefied petroleum gases, vapor pressure can be be provided.
considered a semi-quantitative measure of the amount of the
9.2 Purging—With the assembled apparatus in an upright
most volatile material present in the product, and this can give
position, connect the inlet valve of the lower chamber to the
an indication of low temperature operability.
sample source with the sampling connection (7.2). Open the
sample source valve to the apparatus. Cautiously open the
6. Apparatus
bleeder valve on the upper chamber, permitting the air or
6.1 Vapor Pressure Apparatus, constructed as illustrated in
vapors, or both, in the apparatus to escape until the apparatus
Fig. A1.1, and the various items of auxiliary equipment are
is full of liquid. Close the lower chamber inlet valve and open
completely described in Annex A1.
the bleeder valve to its wide-open position. Allow the con-
tained liquid to evaporate until the apparatus is covered with
6.2 The vapor chamber of Test Method D323 can be
white frost (may require more than one chilling), then invert
interchangeable with the upper chamber of this method.
the assembly, and expel any residual material through the
Similarly, the liquid chamber (two-opening type) of Test
bleeder valve. Allow the residual vapors to escape until the
Method D323 is interchangeable with the B, 20 % lower
pressure in the apparatus is essentially atmospheric, then close
chamber in A1.1.4 of this method. Because of this
the bleeder valve.
interchangeability, the apparatus assembly of Test Method
D323 shall pass, as a safety precaution, the hydrostatic test
9.3 Sampling—Return the apparatus, now containing only
specified in A1.1.6 before using it in testing liquefied petro-
vapors, to its normal upright position and open the inlet valve.
leum gas.
As soon as the apparatus attains essentially the same pressure
as the pressure of the sample source, momentarily open the
6.3 Water Bath, temperature controlled, of a size suitable for
bleeder valve. If liquid does not promptly emerge, repeat the
the vapor pressure apparatus. See A1.3.
purging step (9.2). If liquid appears immediately, close the
6.4 Temperature Measuring Device, of verified accuracy
bleeder and inlet valves in that order (Note 2). Close the valve
and capable of monitoring the desired test temperature in the
on the sample source, and disconnect the sampling line.
water bath in the range of 35 °C to 70 °C to within 60.1 °C.
Immediately close the straight-through valve between the two
6.5 Barometer—A pressure measuring device capable of
chambers and open the inlet valve, with the apparatus in an
measuring local station pressure with an accuracy of 0.1 kPa
upright position. Close the inlet valve as soon as no more liquid
(1 mm Hg) or better, at the same elevation relative to sea level
escapes, and immediately open the straight-through valve.
as the apparatus in the laboratory. (Warning—Do not take
NOTE 2—Transfer of the sample is facilitated by chilling the apparatus
readings from ordinary aneroid barometers, such as those used
with a portion of the material under test.
at weather stations and airports, since these are pre-corrected to
9.3.1 When using the 33 ⁄3 % lower chamber (A1.1.3),
give sea level readings.)
proceed to 9.4.
9.3.2 When using the 20 % lower chamber (A1.1.4), close
7. Sampling and Sample Handling
the straight-through valve and again open the inlet to permit
7.1 Samples shall be obtained and stored in accordance with
expulsion of the lower chamber contents. As soon as no more
Practice D1265 unless the test samples can be taken directly
liquid escapes from the lower chamber, close the inlet valve
from the source of the material to be tested.
and immediately open the straight-through valve.
7.2 Any method of coupling the vapor pressure apparatus to
9.3.3 The upper chamber, prior to this operation, is liquid
the sample source may be employed. Tubing, 6 mm to 7 mm
full at some temperature that is normally below the environ-
( ⁄4 in.) in diameter, of minimum length, of suitable working
mental temperature. Since any warming of the apparatus would
pressure, and made of material corrosion-resistant to the
cause expansion of the liquid content of the upper chamber,
products being sampled, is satisfactory for this purpose. A
leading to possible rupture of the chamber, it is necessary that
flexible tubing connection of a satisfactory type greatly facili-
the procedural steps of providing free space in the apparatus
tates the purging and sampling operations. The tubing should
be completed promptly.
be a conducting material or constructed with a built-in ground
9.4 Vapor Pressure Determination:
connection to minimize the effect of static electricity.
9.4.1 Invert the apparatus and shake it vigorously. Return
the apparatus to its normal upright position and immerse it in
8. Preparation of Apparatus
the constant-temperature water bath maintained at the test
8.1 If the apparatus has been used for testing products other
temperature (4.1). The apparatus including the bleeder valve
than the type of product to be tested, disassemble, clean
coupling, but not the pressure gauge, must be immersed.
thoroughly, and purge the parts in a stream of dry air.
Throughout the determination, the temperature of the water
8.2 Assemble the apparatus with the inlet valve of the lower bath shall be checked periodically by means of the temperature
chamber open, the straight-through valve between the two measuring device.
chambers open, the bleeder valve closed, and with the proper 9.4.1.1 At test temperatures from 37.8 °C (100 °F) up to and
range pressure gauge attached. including 50 °C (122 °F), maintain the bath at 60.1 °C
D1267 − 23
(0.2 °F). At test temperatures above 50 °C (122 °F), up to and 5corrected vapor pressure, psi 2 760 2 P 0.0193 (2)
~ !
including 70 °C (158 °F), maintain the bath at 60.3 °C
where:
(0.5 °F).
P = observed barometric pressure, mm Hg.
9.4.1.2 Observe the apparatus assembly throughout the test
period to ensure freedom from leaks. Discontinue the test and 10.2.2 LP-Gas Vapor Pressure:
discard the results at any time a leak is detected.
5corrected vapor pressure, kPa 2 29.92 2 P 3.3864 (3)
~ !
9.4.2 After 5 min have elapsed, withdraw the apparatus
5corrected vapor pressure, psi 2 ~29.92 2 P ! 0.4912 (4)
from the water bath, invert it, shake it vigorously, and then
return it to the bath. Perform the shaking operation quickly to
...

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.
Designation: D1267 − 18 D1267 − 23
Standard Test Method for
Gauge Vapor Pressure of Liquefied Petroleum (LP) Gases
(LP-Gas Method)
This standard is issued under the fixed designation D1267; 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*
1.1 This test method covers the determination of the gauge vapor pressures of liquefied petroleum gas products at temperatures
of 37.8 °C (100 °F) up to and including a test temperature of 70 °C (158 °F). (Warning—Extremely flammable gas. May be
harmful when inhaled.)
NOTE 1—An alternative method for measurement of vapor pressure of liquefied petroleum gases is Test Method D6897.
1.2 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for
information only and are not considered standard.
1.3 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. For specific warning statements, see 1.1 and Annex A2.
1.4 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:
D323 Test Method for Vapor Pressure of Petroleum Products (Reid Method)
D1265 Practice for Sampling Liquefied Petroleum (LP) Gases, Manual Method
D4175 Terminology Relating to Petroleum Products, Liquid Fuels, and Lubricants
D6897 Test Method for Vapor Pressure of Liquefied Petroleum Gases (LPG) (Expansion Method)
3. Terminology
3.1 Definitions:
3.1.1 For definitions of terms used in this test method, refer to Terminology D4175.
3.1.2 liquefied petroleum gas (LP gas, LPG), n—aa narrow boiling range mixture of hydrocarbons consisting of propane,
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.H0 on Liquefied Petroleum Gas.
Current edition approved July 1, 2018March 1, 2023. Published August 2018March 2023. Originally approved in 1953. Last previous edition approved in 20122018 as
D1267 – 12.D1267 – 18. DOI: 10.1520/D1267-18.10.1520/D1267-23.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. 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
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D1267 − 23
propylene, butanes, and butylenes, individually or in specified combinations, with limited amounts of other hydrocarbons (such
as ethane) and may contain naturally occurring, petroleum-derived non-hydrocarbons.
3.1.3 vapor pressure, n—the pressure exerted by the vapor of a liquid when in equilibrium with the liquid.
4. Summary of Test Method
4.1 The test apparatus, consisting of two interconnected chambers and equipped with a suitable pressure gauge, is purged with a
portion of the sample which is then discarded. The apparatus is then filled completely with the portion of the sample to be tested.
Thirty-three and one-third to forty volume percent of the sample content of the apparatus is immediately withdrawn to provide
adequate free space for product expansion. The apparatus is then immersed in a water bath maintained at the standard test
temperature of 37.8 °C (100 °F) or, optionally, at some higher test temperature up to and including a test temperature of 70 °C
(158 °F).
4.2 The observed gauge pressure at equilibrium, after correcting for gauge error and correcting to a standard barometric pressure,
is reported as the LPG Vapor Pressure at the selected test temperature.
5. Significance and Use
5.1 Information on the vapor pressures of liquefied petroleum gas products under temperature conditions from 37.8 °C to 70 °C
(100 °F to 158 °F) is pertinent to selection of properly designed storage vessels, shipping containers, and customer utilization
equipment to ensure safe handling of these products.
5.2 Determination of the vapor pressure of liquefied petroleum gas is important for safety reasons to ensure that the maximum
operating design pressures of storage, handling, and fuel systems will not be exceeded under normal operating temperature
conditions.
5.3 For liquefied petroleum gases, vapor pressure can be considered a semi-quantitative measure of the amount of the most volatile
material present in the product, and this can give an indication of low temperature operability.
6. Apparatus
6.1 Vapor Pressure Apparatus, constructed as illustrated in Fig. A1.1, and the various items of auxiliary equipment are completely
described in Annex A1.
6.2 The vapor chamber of Test Method D323 can be interchangeable with the upper chamber of this method. Similarly, the liquid
chamber (two-opening type) of Test Method D323 is interchangeable with the B, 20 % lower chamber in A1.1.4 of this method.
Because of this interchangeability, the apparatus assembly of Test Method D323 shall pass, as a safety precaution, the hydrostatic
test specified in A1.1.6 before using it in testing liquefied petroleum gas.
6.3 Water Bath, temperature controlled, of a size suitable for the vapor pressure apparatus. See A1.3.
6.4 Temperature Measuring Device, of verified accuracy and capable of monitoring the desired test temperature in the water bath
in the range of 35 °C to 70 °C to within 60.1 °C.
6.5 Barometer—A pressure measuring device capable of measuring local station pressure with an accuracy of 0.1 kPa (1 mm Hg)
or better, at the same elevation relative to sea level as the apparatus in the laboratory. (Warning—Do not take readings from
ordinary aneroid barometers, such as those used at weather stations and airports, since these are pre-corrected to give sea level
readings.)
7. Sampling and Sample Handling
7.1 Samples shall be obtained and stored in accordance with Practice D1265 unless the test samples can be taken directly from
the source of the material to be tested.
7.2 Any method of coupling the vapor pressure apparatus to the sample source may be employed. Tubing, 6 mm to 7 mm ( ⁄4 in.)
D1267 − 23
in diameter, of minimum length, of suitable working pressure, and made of material corrosion-resistant to the products being
sampled, is satisfactory for this purpose. A flexible tubing connection of a satisfactory type greatly facilitates the purging and
sampling operations. The tubing should be a conducting material or constructed with a built-in ground connection to minimize the
effect of static electricity.
8. Preparation of Apparatus
8.1 If the apparatus has been used for testing products other than the type of product to be tested, disassemble, clean thoroughly,
and purge the parts in a stream of dry air.
8.2 Assemble the apparatus with the inlet valve of the lower chamber open, the straight-through valve between the two chambers
open, the bleeder valve closed, and with the proper range pressure gauge attached.
9. Procedure
9.1 Safe means for the disposal of vapors and liquids during this operation and in the subsequent sampling operation shall be
provided.
9.2 Purging—With the assembled apparatus in an upright position, connect the inlet valve of the lower chamber to the sample
source with the sampling connection (7.2). Open the sample source valve to the apparatus. Cautiously open the bleeder valve on
the upper chamber, permitting the air or vapors, or both, in the apparatus to escape until the apparatus is full of liquid. Close the
lower chamber inlet valve and open the bleeder valve to its wide-open position. Allow the contained liquid to evaporate until the
apparatus is covered with white frost (may require more than one chilling), then invert the assembly, and expel any residual
material through the bleeder valve. Allow the residual vapors to escape until the pressure in the apparatus is essentially
atmospheric, then close the bleeder valve.
9.3 Sampling—Return the apparatus, now containing only vapors, to its normal upright position and open the inlet valve. As soon
as the apparatus attains essentially the same pressure as the pressure of the sample source, momentarily open the bleeder valve.
If liquid does not promptly emerge, repeat the purging step (9.2). If liquid appears immediately, close the bleeder and inlet valves
in that order (Note 2). Close the valve on the sample source, and disconnect the sampling line. Immediately close the
straight-through valve between the two chambers and open the inlet valve, with the apparatus in an upright position. Close the inlet
valve as soon as no more liquid escapes, and immediately open the straight-through valve.
NOTE 2—Transfer of the sample is facilitated by chilling the apparatus with a portion of the material under test.
9.3.1 When using the 33 ⁄3 % lower chamber (A1.1.3), proceed to 9.4.
9.3.2 When using the 20 % lower chamber (A1.1.4), close the straight-through valve and again open the inlet to permit expulsion
of the lower chamber contents. As soon as no more liquid escapes from the lower chamber, close the inlet valve and immediately
open the straight-through valve.
9.3.3 The upper chamber, prior to this operation, is liquid full at some temperature that is normally below the environmental
temperature. Since any warming of the apparatus would cause expansion of the liquid content of the upper chamber, leading to
possible rupture of the chamber, it is necessary that the procedural steps of providing free space in the apparatus be completed
promptly.
9.4 Vapor Pressure Determination:
9.4.1 Invert the apparatus and shake it vigorously. Return the apparatus to its normal upright position and immerse it in the
constant-temperature water bath maintained at the test temperature (4.1). The apparatus including the bleeder valve coupling, but
not the pressure gauge, must be immersed. Throughout the determination, the temperature of the water bath shall be checked
periodically by means of the temperature measuring device.
9.4.1.1 At test temperatures from 37.8 °C (100 °F) up to and including 50 °C (122 °F), maintain the bath at 60.1 °C (0.2 °F). At
test temperatures above 50 °C (122 °F), up to and including 70 °C (158 °F), maintain the bath at 60.3 °C (0.5 °F).
D1267 − 23
9.4.1.2 Observe the apparatus assembly throughout the test period to ensure freedom from leaks. Discontinue the test and discard
the results at any time a leak is detected.
9.4.2 After 5 min have elapsed, withdraw the apparatus from the water bath, invert it, shake it vigorously, and then return it to
the bath. Perform the shaking operation quickly to avoid excessive cooling of the apparatus and its contents. Thereafter, at intervals
of not less than 2 min, withdraw the apparatus from the bath, invert, shake it vigorously, and then return it to the bath. Prior to
each removal of the apparatus from the water bath, tap the gauge lightly and
...