ASTM D1988-06(2015)
(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
4.1 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 fade over time.
4.2 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 proper 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 5 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 and health practices and determine the applicability of regulatory limitations prior to use. For specific hazard statements, see 7.3.
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Designation: D1988 − 06 (Reapproved 2015)
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 Detector Tubes, Appendix B, Test for Ethyl Mercaptan
2
Odourant in Propane, Field Method, 1988
1.1 This test method covers a rapid and simple field deter-
mination of mercaptans in natural gas pipelines. Available
3. Summary of Test Method
detector tubes provide a total measuring range of 0.5 to 160
3.1 The sample is passed through a detector tube filled with
ppm by volume of mercaptans, although the majority of
a specially prepared chemical. Any mercaptan present in the
applications will be on the lower end of this range (that is,
sample reacts with the chemical to produce a color change, or
under 20 ppm). Besides total mercaptans, detector tubes are
stain. The length of the stain produced in the detector tube,
also available for methyl mercaptan (0.5 to 100 ppm), ethyl
when exposed to a measured volume of sample, is directly
mercaptan (0.5 to 120 ppm), and butyl mercaptan (0.5 to 30
3
proportional to the amount of mercaptan present in the sample.
mg/M or 0.1 to 8 ppm).
A hand-operated piston or bellows-type pump is used to draw
NOTE 1—Certain detector tubes are calibrated in terms of milligrams
3 a measured volume of sample through the tube at a controlled
per cubic metre (mg/M ) instead of parts per million by volume. The
rate of flow. The length of stain produced is converted to parts
conversion is as follows for 25°C (77°F) and 760 mm Hg.
per million (ppm) by volume mercaptan by comparison to a
ppm 3molecular weight
3
calibration scale supplied by the manufacturer for each box of
mg/M 5 (1)
24.45
detection tubes. The system is direct reading, easily portable,
1.2 Detector tubes are usually subject to interferences from
and completely suited to making rapid spot checks for mer-
gases and vapors other than the target substance. Such inter-
captans under field conditions (see Note 1).
ferencesmayvaryamongbrandsbecauseoftheuseofdifferent
detection principles. Many detector tubes will have a pre-
4. Significance and Use
cleanse layer designed to remove interferences up to some
4.1 The measurement of mercaptans in natural gas is
maximum level. Consult manufacturer’s instructions for spe-
important, because mercaptans are often added as odorants to
cific interference information. Hydrogen sulfide and other
natural gas to provide a warning property. The odor provided
mercaptans are usually interferences on mercaptan detector
by the mercaptan serves to warn consumers (for example,
tubes. See Section 5 for interferences of various methods of
residentialuse)ofnaturalgasleaksatlevelsthatarewellbelow
detection.
theflammableorsuffocatingconcentrationlevelsofnaturalgas
1.3 This standard does not purport to address all of the
in air. Field determinations of mercaptans in natural gas are
safety concerns, if any, associated with its use. It is the
important because of the tendency of the mercaptan concen-
responsibility of the user of this standard to establish appro-
tration to fade over time.
priate safety and health practices and determine the applica-
4.2 This test method provides inexpensive field screening of
bility of regulatory limitations prior to use. For specific hazard
mercaptans. The system design is such that it may be used by
statements, see 7.3.
nontechnical personnel, with a minimum of proper training.
2. Referenced Documents
5. Interferences
2.1 Gas Processors Association Standard:
GPAStandard 2188 Tentative Method for the Determination 5.1 Interference from hydrogen sulfide gas (H S) is a
2
of Ethyl Mercaptan in LP Gas Using Length-of-Stain common problem with mercaptan detector tubes and its extent
should be understood to make use of tube readings. There are
1
ThistestmethodisunderthejurisdictionofASTMCommitteeD03onGaseous at least three detection principles used in mercaptan detector
Fuels and is the direct responsibility of Subcommittee D03.07 on Analysis of
tubes and each is summarized below.
Chemical Composition of Gaseous Fuels.
Current edition approved Nov. 1, 2015. Published December 2015. Originally
approved in 1991. Last previous edition approved in 2011 as D1988 –06 (2011).
2
DOI: 10.1520/D1988-06R15. Available from Gas ProcessorsAssociation, 6526 E. 60th St.,Tulsa, OK 74145.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
...
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 2011) D1988 − 06 (Reapproved 2015)
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
3
mercaptan (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) 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 5 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 and health practices and determine the applicability of regulatory
limitations prior to use. For specific hazard statements, see 7.3.
2. Referenced Documents
2.1 Gas Processors Association Standard:
GPA Standard 2188 Tentative Method for the Determination of Ethyl Mercaptan in LP Gas Using Length-of-Stain Detector
2
Tubes, Appendix B, Test for Ethyl Mercaptan Odourant in Propane, Field Method, 1988
3. Summary of Test Method
3.1 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 detection tubes. The system is direct reading, easily portable, and completely suited to making rapid
spot checks for mercaptans under field conditions (see Note 1).
4. Significance and Use
4.1 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
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, 2011Nov. 1, 2015. Published March 2012December 2015. Originally approved in 1991. Last previous edition approved in 20062011 as
D1988 –06. –06 (2011). DOI: 10.1520/D1988-06R11.10.1520/D1988-06R15.
2
Available from Gas Processors Association, 6526 E. 60th St., Tulsa, OK 74145.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D1988 − 06 (2015)
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 fade over
time.
4.2 This test method provides inexpensive field screening of mercapt
...
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