ASTM D4888-06

Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes

SIGNIFICANCE AND USE
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.
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. Availabel 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.

General Information

• Status: Historical
• Publication Date: 31-May-2006
• ICS: 75.060 - Natural gas
• Technical Committee: D03 - Gaseous Fuels

Relations

• Replaces: ASTM D4888-88(1999) - Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes
• Effective Date: 01-Jun-2006
• Replaced By: ASTM D4888-06(2011) - Standard Test Method for Water Vapor in Natural Gas Using Length-of-Stain Detector Tubes
• Effective Date: 01-Nov-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:D4888–06
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 and completely suited to making rapid spot checks for water
vapor under field conditions.
1.1 This test method covers a procedure for rapid and
simple field determination of water vapor in natural gas
NOTE 1—Detector tubes are available with calibration scales printed in
pipelines. Availabel detector tubes provide a total measuring
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).
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).
3. Significance and Use
At least one manufacturer provides tubes that read directly in
3.1 The measurement of water vapor in natural gas is
pounds of water per million cubic feet of gas. See Note 1.
important because of the gas quality specifications, the corro-
1.2 Detector tubes are usually subject to interferences from
sive nature of water vapor on pipeline materials, and the effects
gases and vapors other than the target substance. Such inter-
of water vapor on utilization equipment.
ferencesmayvaryamongbrandsbecauseoftheuseofdifferent
3.2 This test method provides inexpensive field screening of
detection methods. Consult manufacturer’s instructions for
water vapor. The system design is such that it may be used by
specific interference information. Alcohols and glycols will
nontechnical personnel with a minimum of proper training.
cause interferences on some water vapor tubes because of the
presence of the hydroxyl group on those molecules.
4. Apparatus
1.3 This standard does not purport to address all of the
4.1 Length-of-Stain Detector Tubes—A sealed glass tube
safety concerns, if any, associated with its use. It is the
with the breakoff tips sized to fit the tube holder of the pump.
responsibility of the user of this standard to establish appro-
Thereagentlayerinsidethetube,typicallyasilicagelsubstrate
priate safety and health practices and determine the applica-
coated with the active chemical, must be specific for water
bility of regulatory limitations prior to use.
vapor and produce a distinct color change when exposed to a
2. Summary of Test Method
sample of gas containing water vapor. Any substances known
to interfere must be listed in the instructions accompanying the
2.1 The sample is passed through a detector tube filled with
tubes. A calibration scale should be marked directly on the
a specially prepared chemical. Any water vapor present in the
tube; however, other markings that provide for ready interpre-
sample reacts with the chemical to produce a color change or
tation of water vapor content from a separate calibration scale
stain. The length of the stain produced in the detector tube,
supplied with the tubes shall be acceptable. The calibration
when exposed to a measured volume of sample, is directly
scale shall correlate water vapor concentration to the length of
proportional to the amount of water vapor present in the
the color stain. Shelf life of the detector tubes must be a
sample. A hand-operated piston or bellows-type pump is used
minimum of two years from date of manufacture when stored
to draw a measured volume of sample through the tube at a
according to manufacturers’ recommendations.
controlled rate of flow. The length of stain produced is
4.2 Detector Tube Pump—A hand-operated pump of a
converted to milligrams per litre of H O by comparison to a
2
piston or bellows type. It must be capable of drawing 100 mL
calibration scale supplied by the manufacturer for each box of
per stroke of sample through the detector tube with a volume
detection tubes. The system is direct reading, easily portable,
2
tolerance of 65 mL. It must be specifically designed for use
with detector tubes.
1 NOTE 2—A detector tube and pump together form a unit and must be
This test method is under the jurisdiction of Committee D03 on Gaseous Fuels
used as such. Each manufacturer calibrates detector tubes to match the
and is the direct responsibility of Subcommittee D03.07 Analysis of Chemical
Composition of Gaseous Fuels.
Current edition approved June 1, 2006. Published June 2006. Originally
2
approved in 1988. Last previous edition approved in 1999 as D4888 – 88 (1999). Direct Reading Colorimetric Indicator Tubes Manual , First ed., American
DOI: 10.1520/D4888-06. Industrial Hygiene Association, Akron,
...