ASTM D4888-06(2015)
(Test Method)Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes
Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes
SIGNIFICANCE AND USE
3.1 The measurement of water vapor in natural gas is important because of the gas quality specifications, the corrosive nature of water vapor on pipeline materials, and the effects of water vapor on utilization equipment.
3.2 This test method provides inexpensive field screening of water vapor. 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 procedure for rapid and simple field determination of water vapor in natural gas pipelines. Available detector tubes provide a total measuring range of 0.1 to 40 mg/L, although the majority of applications will be on the lower end of this range (that is, under 0.5 mg/L). At least one manufacturer provides tubes that read directly in pounds of water per million cubic feet of gas. See Note 1.
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 methods. Consult manufacturer's instructions for specific interference information. Alcohols and glycols will cause interferences on some water vapor tubes because of the presence of the hydroxyl group on those molecules.
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.
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Designation: D4888 − 06 (Reapproved 2015)
Standard Test Method for
Water Vapor in Natural Gas Using Length-of-Stain Detector
1
Tubes
This standard is issued under the fixed designation D4888; 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.
NOTE 1—Detector tubes are available with calibration scales printed in
1. Scope
pounds of water per million cubic feet of gas (lb/MMCF). The conversion
1.1 This test method covers a procedure for rapid and
factor is 1 mg/L = 62.3 lb/MMCF (7 lb/MMCF = 0.11 mg ⁄L).
simple field determination of water vapor in natural gas
pipelines. Available detector tubes provide a total measuring 3. Significance and Use
range of 0.1 to 40 mg/L, although the majority of applications
3.1 The measurement of water vapor in natural gas is
will be on the lower end of this range (that is, under 0.5 mg/L).
important because of the gas quality specifications, the corro-
At least one manufacturer provides tubes that read directly in
sive nature of water vapor on pipeline materials, and the effects
pounds of water per million cubic feet of gas. See Note 1.
of water vapor on utilization equipment.
1.2 Detector tubes are usually subject to interferences from
3.2 This test method provides inexpensive field screening of
gases and vapors other than the target substance. Such inter-
water vapor. The system design is such that it may be used by
ferencesmayvaryamongbrandsbecauseoftheuseofdifferent
nontechnical personnel with a minimum of proper training.
detection methods. Consult manufacturer’s instructions for
specific interference information. Alcohols and glycols will
4. Apparatus
cause interferences on some water vapor tubes because of the
4.1 Length-of-Stain Detector Tubes—A sealed glass tube
presence of the hydroxyl group on those molecules.
with the breakoff tips sized to fit the tube holder of the pump.
1.3 This standard does not purport to address all of the
Thereagentlayerinsidethetube,typicallyasilicagelsubstrate
safety concerns, if any, associated with its use. It is the
coated with the active chemical, must be specific for water
responsibility of the user of this standard to establish appro-
vapor and produce a distinct color change when exposed to a
priate safety and health practices and determine the applica-
sample of gas containing water vapor. Any substances known
bility of regulatory limitations prior to use.
to interfere must be listed in the instructions accompanying the
tubes. A calibration scale should be marked directly on the
2. Summary of Test Method
tube; however, other markings that provide for ready interpre-
2.1 The sample is passed through a detector tube filled with
tation of water vapor content from a separate calibration scale
a specially prepared chemical. Any water vapor present in the
supplied with the tubes shall be acceptable. The calibration
sample reacts with the chemical to produce a color change or
scale shall correlate water vapor concentration to the length of
stain. The length of the stain produced in the detector tube,
the color stain. Shelf life of the detector tubes must be a
when exposed to a measured volume of sample, is directly
minimum of two years from date of manufacture when stored
proportional to the amount of water vapor present in the
according to manufacturers’ recommendations.
sample. A hand-operated piston or bellows-type pump is used
4.2 Detector Tube Pump—A hand-operated pump of a
to draw a measured volume of sample through the tube at a
piston or bellows type. It must be capable of drawing 100 mL
controlled rate of flow. The length of stain produced is
per stroke of sample through the detector tube with a volume
converted to milligrams per litre of H O by comparison to a
2
2
tolerance of 65 mL. It must be specifically designed for use
calibration scale supplied by the manufacturer for each box of
with detector tubes.
detection tubes. The system is direct reading, easily portable,
and completely suited to making rapid spot checks for water
NOTE 2—A detector tube and pump together form a unit and must be
used as such. Each manufacturer calibrates detector tubes to match the
vapor under field conditions.
flow characteristics of its specific pump. Crossing brands of pumps and
tubes is not permitted, as considerable loss of system accuracy is likely to
1
This test method is under the jurisdiction of CommitteeD03 on Gaseous Fuels 2
occur.
and is the direct responsibility of Subcommittee D03.07Analysis of Chemical
Composition of Gaseous Fuels.
Current edition approved Nov. 1, 2015. Published December 2015. Originally
2
approved in 1988. Last previous ed
...
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: D4888 − 06 (Reapproved 2011) D4888 − 06 (Reapproved 2015)
Standard Test Method for
Water Vapor in Natural Gas Using Length-of-Stain Detector
1
Tubes
This standard is issued under the fixed designation D4888; 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 procedure for rapid and simple field determination of water vapor in natural gas pipelines.
AvailabelAvailable detector tubes provide a total measuring range of 0.1 to 40 mg/L, although the majority of applications will
be on the lower end of this range (that is, under 0.5 mg/L). At least one manufacturer provides tubes that read directly in pounds
of water per million cubic feet of gas. See Note 1.
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 methods. Consult manufacturer’s instructions for specific
interference information. Alcohols and glycols will cause interferences on some water vapor tubes because of the presence of the
hydroxyl group on those molecules.
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.
2. Summary of Test Method
2.1 The sample is passed through a detector tube filled with a specially prepared chemical. Any water vapor 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 water vapor 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 milligrams per litre of H O by comparison to a calibration scale supplied by
2
the manufacturer for each box of detection tubes. The system is direct reading, easily portable, and completely suited to making
rapid spot checks for water vapor under field conditions.
NOTE 1—Detector tubes are available with calibration scales printed in pounds of water per million cubic feet of gas (lb/MMCF). The conversion factor
is 1 mg/L = 62.3 lb/MMCF (7 lb/MMCF = 0.11 mg/L).mg ⁄L).
3. Significance and Use
3.1 The measurement of water vapor in natural gas is important because of the gas quality specifications, the corrosive nature
of water vapor on pipeline materials, and the effects of water vapor on utilization equipment.
3.2 This test method provides inexpensive field screening of water vapor. The system design is such that it may be used by
nontechnical personnel with a minimum of proper training.
4. Apparatus
4.1 Length-of-Stain Detector Tubes—A sealed glass tube with the breakoff tips sized to fit the tube holder of the pump. The
reagent layer inside the tube, typically a silica gel substrate coated with the active chemical, must be specific for water vapor and
produce a distinct color change when exposed to a sample of gas containing water vapor. Any substances known to interfere must
be listed in the instructions accompanying the tubes. A calibration scale should be marked directly on the tube; however, other
markings that provide for ready interpretation of water vapor content from a separate calibration scale supplied with the tubes shall
1
This test method is under the jurisdiction of CommitteeD03 on Gaseous Fuels and is the direct responsibility of Subcommittee D03.07Analysis of Chemical Composition
of Gaseous Fuels.
Current edition approved Nov. 1, 2011Nov. 1, 2015. Published July 2012December 2015. Originally approved in 1988. Last previous edition approved in 20062011 as
D4888 – 06.D4888 – 06 (2011). DOI: 10.1520/D4888-06R11.10.1520/D4888-06R15.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D4888 − 06 (2015)
be acceptable. The calibration scale shall correlate water vapor concentration to the length of the color stain. Shelf life of the
detector tubes must be
...
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