ASTM D4230-02e1

Standard Test Method of Measuring Humidity with Cooled-Surface Condensation (Dew-Point) Hygrometer

SIGNIFICANCE AND USE
Humidity information is important for the understanding of atmospheric phenomena and industrial processes. Measurements of the dew-point and calculations of related vapor pressures are important to quantify the humidity information.
SCOPE
1.1 This test method covers the determination of the thermodynamic dew- or frost-point temperature of ambient air by the condensation of water vapor on a cooled surface. For brevity this is referred to in this method as the condensation temperature.
1.2 This test method is applicable for the range of condensation temperatures from 60°C to -70°C.
1.3 This test method includes a general description of the instrumentation and operational procedures, including site selection, to be used for obtaining the measurements and a description of the procedures to be used for calculating the results.
1.4 This test method is applicable for the continuous measurement of ambient humidity in the natural atmosphere on a stationary platform.
1.5 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 precautionary statements, see Section 8.

General Information

• Status: Historical
• Publication Date: 09-Oct-2002
• ICS: 07.060 - Geology. Meteorology. Hydrology
• Technical Committee: D22 - Air Quality
• Drafting Committee: D22.11 - Meteorology

Relations

• Replaces: ASTM D4230-02 - Standard Test Method of Measuring Humidity with Cooled-Surface Condensation (Dew-Point) Hygrometer
• Effective Date: 10-Oct-2002
• Replaced By: ASTM D4230-02(2007) - Standard Test Method of Measuring Humidity with Cooled-Surface Condensation (Dew-Point) Hygrometer
• Effective Date: 01-Oct-2007
• Referred By: ASTM E337-15(2023) - Standard Test Method for Measuring Humidity with a Psychrometer (the Measurement of Wet- and Dry-Bulb Temperatures)
• Effective Date: 10-Oct-2002
• Referred By: ASTM B827-05(2020) - Standard Practice for Conducting Mixed Flowing Gas (MFG) Environmental Tests
• Effective Date: 10-Oct-2002
• Referred By: ASTM F2524-06(2020) - Standard Practice for Determination of Volatile Content for Formed-in-Place Gaskets (FIPG) Silicone Adhesives and Sealants for Transportation Applications
• Effective Date: 10-Oct-2002
• Referred By: ASTM D8122-21 - Standard Test Method for Determining Mass per Unit Area of Geohazard Nettings
• Effective Date: 10-Oct-2002
• Referred By: ASTM D5527-23 - Standard Practices for Measuring Surface Wind and Temperature by Acoustic Means
• Effective Date: 10-Oct-2002
• Referred By: ASTM D5011-17 - Standard Practices for Calibration of Ozone Monitors Using Transfer Standards
• Effective Date: 10-Oct-2002
• Referred By: ASTM D8446-22 - Standard Test Method for Water Vapor Content in Compressed Air Using Electronic Moisture Analyzers
• Effective Date: 10-Oct-2002

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
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Designation:D4230–02
Standard Test Method of
Measuring Humidity with Cooled-Surface Condensation
1
(Dew-Point) Hygrometer
This standard is issued under the fixed designation D4230; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1
e NOTE—Editorial corrections were made throughout the test method in July 2003.
1. Scope 3. Terminology
1.1 This test method covers the determination of the ther- 3.1 Definitions:
modynamic dew- or frost-point temperature of ambient air by 3.1.1 For definitions of other terms in this method, refer to
the condensation of water vapor on a cooled surface. For Terminology D1356.
brevity this is referred to in this method as the condensation 3.2 Definitions of Terms Specific to This Standard:
temperature. 3.2.1 nonhygroscopic material—material that neither ab-
1.2 This test method is applicable for the range of conden- sorbs nor retains water vapor.
sation temperatures from 60°C to−70°C. 3.2.2 mirror (front surface)—a polished surface, usually a
1.3 This test method includes a general description of the metallic surface, on which condensates are deposited.
instrumentation and operational procedures, including site 3.3 Symbols:
selection, to be used for obtaining the measurements and a
description of the procedures to be used for calculating the
e = vapor pressure of water vapor in moist air.
results.
e = saturation pressure of water vapor in equilibrium
i
1.4 This test method is applicable for the continuous mea-
with the plane surface of ice.
surement of ambient humidity in the natural atmosphere on a
e = saturation pressure of water vapor in equilibrium
w
stationary platform.
with the plane surface of water.
1.5 This standard does not purport to address all of the
P = ambient pressure.
safety concerns, if any, associated with its use. It is the
r = mixing ratio.
responsibility of the user of this standard to establish appro-
T = ambient air temperature.
priate safety and health practices and determine the applica-
T = thermodynamic dew- or frost-point temperature.
d
bility of regulatory limitations prior to use. For specific
RH = relative humidity with respect to ice.
i
precautionary statements, see Section 8.
RH = relative humidity with respect to water.
w
2. Referenced Documents
4. Summary of Test Method
2
2.1 ASTM Standards:
4.1 The ambient humidity is measured with a dew- and
D1356 Terminology Relating to Sampling andAnalysis of
frost-point hygrometer.
Atmospheres
4.2 The mirror or some other surface on which the conden-
D3631 Test Methods for Measuring Surface Atmospheric
sate is deposited is provided with the means for cooling and
Pressure
heating, detection of condensate, and the measurement of the
temperature of the mirror surface.
4.3 Calculationsofsaturationvaporpressureoverwaterand
ice as functions of temperature are provided.
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This test method is under the jurisdiction of ASTM Committee D22 on Air
Quality and is the direct responsibility of Subcommittee D22.11 on Meteorology.
5. Significance and Use
Current edition approved October 10, 2002. Published December 2002. Origi-
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nally published as D4230–83. Last previous edition D4230–83(96) .
5.1 Humidityinformationisimportantfortheunderstanding
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
of atmospheric phenomena and industrial processes. Measure-
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
ments of the dew-point and calculations of related vapor
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. pressures are important to quantify the humidity information.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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D4230–02
6. Interferences 8.1.3 Appropriatevoltagesurgeprotectioncircuitrymustbe
incorporated.
6.1 Thismethodisnotapplicableifotherconstituentsinthe
atmosphere condense before water vapor. 8.2 Technical Precautions:
8.2.1 The accuracy of a cooled-surface condensation hy-
7. Apparatus
grometer is degraded by the presence of water-soluble materi-
als. A mirror-cleaning schedule, consistent with the contami-
7.1 Dew-point hygrometers, specifically designed for me-
nation rate, is necessary to maintain the initial calibration
teorological observations are available commercially. A sche-
accuracy. The user must determine the required maintenance
maticarrangementofatypicalopticaldew-pointhygrometeris
shown in Fig. 1. schedule for the specific site, by comparison of calibrations
made before and
...