ASTM D1988-20
(Test Method)Standard Test Method for Mercaptans in Natural Gas Using Length-of-Stain Detector Tubes
Standard Test Method for Mercaptans in Natural Gas Using Length-of-Stain Detector Tubes
SIGNIFICANCE AND USE
5.1 The measurement of mercaptans in natural gas is important, because mercaptans are often added as odorants to natural gas to provide a warning property. The odor provided by the mercaptan serves to warn consumers (for example, residential use) of natural gas leaks at levels that are well below the flammable or suffocating concentration levels of natural gas in air. Field determinations of mercaptans in natural gas are important because of the tendency of the mercaptan concentration to decline over time.
5.2 This test method provides inexpensive field screening of mercaptans. The system design is such that it may be used by nontechnical personnel, with a minimum of training.
SCOPE
1.1 This test method covers a rapid and simple field determination of mercaptans in natural gas pipelines. Available detector tubes provide a total measuring range of 0.5 to 160 ppm by volume of mercaptans, although the majority of applications will be on the lower end of this range (that is, under 20 ppm). Besides total mercaptans, detector tubes are also available for methyl mercaptan (0.5 to 100 ppm), ethyl mercaptan (0.5 to 120 ppm), and butyl mercaptan (0.5 to 30 mg/M3 or 0.1 to 8 ppm).
Note 1: Certain detector tubes are calibrated in terms of milligrams per cubic metre (mg/M3) instead of parts per million by volume. The conversion is as follows for 25 °C (77 °F) and 760 mm Hg.
1.2 Detector tubes are usually subject to interferences from gases and vapors other than the target substance. Such interferences may vary among brands because of the use of different detection principles. Many detector tubes will have a precleanse layer designed to remove interferences up to some maximum level. Consult manufacturer's instructions for specific interference information. Hydrogen sulfide and other mercaptans are usually interferences on mercaptan detector tubes. See Section 6 for interferences of various methods of detection.
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 hazard statements, see 8.3.
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.
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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: D1988 − 20
Standard Test Method for
Mercaptans in Natural Gas Using Length-of-Stain Detector
1
Tubes
This standard is issued under the fixed designation D1988; 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 mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
1.1 This test method covers a rapid and simple field deter-
mination of mercaptans in natural gas pipelines. Available
2. Referenced Documents
detector tubes provide a total measuring range of 0.5 to 160
2
2.1 ASTM Standards:
ppm by volume of mercaptans, although the majority of
D4150 Terminology Relating to Gaseous Fuels
applications will be on the lower end of this range (that is,
3
2.2 GPA Standard:
under 20 ppm). Besides total mercaptans, detector tubes are
GPA 2188 Method for the Determination of Ethyl Mercaptan
also available for methyl mercaptan (0.5 to 100 ppm), ethyl
in LP-Gas Using Length of Stain Tubes
mercaptan (0.5 to 120 ppm), and butyl mercaptan (0.5 to 30
3
mg/M or 0.1 to 8 ppm).
3. Terminology
NOTE 1—Certain detector tubes are calibrated in terms of milligrams
3.1 Definitions—For definitions of general terms used in
3
per cubic metre (mg/M ) instead of parts per million by volume. The
D03 Gaseous Fuels standards, refer to Terminology D4150.
conversion is as follows for 25 °C (77 °F) and 760 mm Hg.
ppm × molecular weight
4. Summary of Test Method
3
mg/M 5 (1)
24.45
4.1 The sample is passed through a detector tube filled with
1.2 Detector tubes are usually subject to interferences from
a specially prepared chemical. Any mercaptan present in the
gases and vapors other than the target substance. Such inter-
sample reacts with the chemical to produce a color change, or
ferences may vary among brands because of the use of different
stain. The length of the stain produced in the detector tube,
detection principles. Many detector tubes will have a pre-
when exposed to a measured volume of sample, is directly
cleanse layer designed to remove interferences up to some
proportional to the amount of mercaptan present in the sample.
maximum level. Consult manufacturer’s instructions for spe-
A hand-operated piston or bellows-type pump is used to draw
cific interference information. Hydrogen sulfide and other
a measured volume of sample through the tube at a controlled
mercaptans are usually interferences on mercaptan detector
rate of flow. The length of stain produced is converted to parts
tubes. See Section 6 for interferences of various methods of
per million (ppm) by volume mercaptan by comparison to a
detection.
calibration scale supplied by the manufacturer for each box of
1.3 This standard does not purport to address all of the detection tubes. The system is direct reading, easily portable,
and completely suited to making rapid spot checks for mer-
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- captans under field conditions (see Note 1).
priate safety, health, and environmental practices and deter-
5. Significance and Use
mine the applicability of regulatory limitations prior to use.
For specific hazard statements, see 8.3. 5.1 The measurement of mercaptans in natural gas is
1.4 This international standard was developed in accor-
important, because mercaptans are often added as odorants to
dance with internationally recognized principles on standard- natural gas to provide a warning property. The odor provided
ization established in the Decision on Principles for the
by the mercaptan serves to warn consumers (for example,
Development of International Standards, Guides and Recom- residential use) of natural gas leaks at levels that are well below
1 2
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Fuels and is the direct responsibility of Subcommittee D03.06.03 on Analysis by contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Spectroscopy. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Dec. 15, 2020. Published January 2021. Originally the ASTM website.
3
approved in 1991. Last previous edition approved in 2015 as D1988 – 06(2015). Available from Gas Processors Association (GPA), 6060 American Plaza, Suite
DOI: 10.1520/D1988-20. 700, Tulsa, OK 74135, http://www.gpaglobal.org
...
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: D1988 − 06 (Reapproved 2015) D1988 − 20
Standard Test Method for
Mercaptans in Natural Gas Using Length-of-Stain Detector
1
Tubes
This standard is issued under the fixed designation D1988; 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 a rapid and simple field determination of mercaptans in natural gas pipelines. Available detector tubes
provide a total measuring range of 0.5 to 160 ppm by volume of mercaptans, although the majority of applications will be on the
lower end of this range (that is, under 20 ppm). Besides total mercaptans, detector tubes are also available for methyl mercaptan
3
(0.5 to 100 ppm), ethyl mercaptan (0.5 to 120 ppm), and butyl mercaptan (0.5 to 30 mg/M or 0.1 to 8 ppm).
3
NOTE 1—Certain detector tubes are calibrated in terms of milligrams per cubic metre (mg/M ) instead of parts per million by volume. The conversion
is as follows for 25°C (77°F)25 °C (77 °F) and 760 mm Hg.
ppm 3molecular weight
3
mg/M 5 (1)
24.45
1.2 Detector tubes are usually subject to interferences from gases and vapors other than the target substance. Such interferences
may vary among brands because of the use of different detection principles. Many detector tubes will have a precleanse layer
designed to remove interferences up to some maximum level. Consult manufacturer’s instructions for specific interference
information. Hydrogen sulfide and other mercaptans are usually interferences on mercaptan detector tubes. See Section 56 for
interferences of various methods of detection.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use. For specific hazard statements, see 7.38.3.
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
2.1 ASTM Standards:
D4150 Terminology Relating to Gaseous Fuels
1
This test method is under the jurisdiction of ASTM Committee D03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of Chemical
Composition of Gaseous Fuels.
Current edition approved Nov. 1, 2015Dec. 15, 2020. Published December 2015January 2021. Originally approved in 1991. Last previous edition approved in 20112015
as D1988D1988 – 06 –06 (2011). (2015). DOI: 10.1520/D1988-06R15.10.1520/D1988-20.
2
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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D1988 − 20
3
2.2 Gas Processors Association GPA Standard:
GPA Standard 21882188 Tentative Method for the Determination of Ethyl Mercaptan in LP Gas Using Length-of-Stain Detector
Tubes, Appendix B, Test for Ethyl Mercaptan Odourant in Propane, Field Method, 1988LP-Gas Using Length of Stain Tubes
3. Terminology
3.1 Definitions—For definitions of general terms used in D03 Gaseous Fuels standards, refer to Terminology D4150.
4. Summary of Test Method
4.1 The sample is passed through a detector tube filled with a specially prepared chemical. Any mercaptan present in the sample
reacts with the chemical to produce a color change, or stain. The length of the stain produced in the detector tube, when exposed
to a measured volume of sample, is directly proportional to the amount of mercaptan present in the sample. A hand-operated piston
or bellows-type pump is used to draw a measured volume of sample through the tube at a controlled rate of flow. The length of
stain produced is converted to parts per million (ppm) by volume mercaptan by comparison to a calibration scale supplied by the
manufacturer for each box of detec
...
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