ASTM F2298-03(2009)e1
(Test Method)Standard Test Methods for Water Vapor Diffusion Resistance and Air Flow Resistance of Clothing Materials Using the Dynamic Moisture Permeation Cell (Withdrawn 2015)
Standard Test Methods for Water Vapor Diffusion Resistance and Air Flow Resistance of Clothing Materials Using the Dynamic Moisture Permeation Cell (Withdrawn 2015)
SIGNIFICANCE AND USE
The water vapor transport properties of textile materials are of considerable importance in determining the comfort properties of clothing systems. Water vapor transport through porous textiles may occur due to both diffusion (driven by vapor concentration differences) and convection (driven by gas pressure differences).
For air permeable porous materials, a very small pressure gradient can produce large convective flows through the pores in the structure. In many standard water vapor permeability test methods, when used for materials with high air permeability, slight variations in pressure gradient across a specimen will greatly influence the measured water vapor transport properties. Therefore, the water vapor transport properties of the porous and non-porous textile materials cannot be directly compared when the method has no provision for controlling the pressure gradient. This test method determines the diffusion and convection properties from the same test and generates data that allows direct comparison of the results obtained between materials.
SCOPE
1.1 This test method covers the measurement of the moisture vapor transport and gas flow properties of fabrics, membranes, and membrane laminates used for protective materials.
1.2 The values stated in SI units are to be regarded as the standard.
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.
WITHDRAWN RATIONALE
This test method covered the measurement of the moisture vapor transport and gas flow properties of fabrics, membranes, and membrane laminates used for protective materials.
Formerly under the jurisdiction of Committee F23 on Personal Protective Clothing and Equipment, this test method was withdrawn in February 2015. This standard is being withdrawn without replacement due to its limited use by industry.
General Information
Relations
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
´1
Designation: F2298 − 03(Reapproved 2009)
Standard Test Methods for
Water Vapor Diffusion Resistance and Air Flow Resistance
of Clothing Materials Using the Dynamic Moisture
Permeation Cell
This standard is issued under the fixed designation F2298; 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 (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Reapproved with editorial changes in February 2009.
1. Scope 3.1.2 water vapor transmission rate, n— the steady water
vapor flow in unit time through unit area of a material, under
1.1 This test method covers the measurement of the mois-
specific conditions of temperature and humidity at each sur-
ture vapor transport and gas flow properties of fabrics,
face.
membranes, and membrane laminates used for protective
materials.
4. Summary of Test Methods
1.2 The values stated in SI units are to be regarded as the
4.1 The testing outlined in this standard consists of measur-
standard.
ingtheamountofwatervaportransportacrossaspecimen.The
1.3 This standard does not purport to address all of the
water vapor transport properties can be measured in a pure
safety concerns, if any, associated with its use. It is the
diffusion mode and in a diffusion/convection mode.
responsibility of the user of this standard to establish appro-
4.2 Two test methods are presented in this standard:
priate safety and health practices and determine the applica-
4.2.1 Part A (Diffusion Test)—The test is done under the
bility of regulatory limitations prior to use.
maximum difference in relative humidity and zero pressure
gradient across the specimen so that only the water vapor
2. Referenced Documents
diffusion transport through the specimen is measured (Fig. 1).
2.1 ASTM Standards:
4.2.2 Part B (Combined Convection/Diffusion Test)—A se-
D737Test Method for Air Permeability of Textile Fabrics
ries of pressure gradients is applied in specified increments to
2.2 Other Standards:
force air through the material (Fig. 1). Thus, the test is
ISO 11092Textiles—Physiological Effects—Measurement
conducted under a combined air pressure gradient and concen-
of Thermal and Water-Vapour Resistance Under Steady-
tration gradient that allows examination of the interaction of
State Conditions (Sweating Guarded-Hotplate Test)
convective and diffusive mass transfer across the specimen.
JIS L 1099Testing Methods for Water Vapour Permeability
This method is designed for use on relatively air-permeable
of Clothes
textile materials because for air-impermeable materials, the
results will be the same as the diffusion test alone.
3. Terminology
3.1 Definitions:
5. Significance and Use
3.1.1 water vapor diffusion, n—the process by which water
5.1 The water vapor transport properties of textile materials
vapor molecules move from a region of high concentration to
are of considerable importance in determining the comfort
a region of low concentration.
properties of clothing systems. Water vapor transport through
porous textiles may occur due to both diffusion (driven by
These test methods are under the jurisdiction of ASTM Committee F23 on
vaporconcentrationdifferences)andconvection(drivenbygas
Personal Protective Clothing and Equipment and are the direct responsibility of
pressure differences).
Subcommittee F23.60 on Human Factors.
Current edition approved Feb. 1, 2009. Published March 2009. Originally
5.2 For air permeable porous materials, a very small pres-
approved in 2003. Last previous edition approved in 2003 as F2298-03. DOI:
sure gradient can produce large convective flows through the
10.1520/F2298-03R09E01.
pores in the structure. In many standard water vapor perme-
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
ability test methods, when used for materials with high air
Standards volume information, refer to the standard’s Document Summary page on
permeability, slight variations in pressure gradient across a
the ASTM website.
3 specimen will greatly influence the measured water vapor
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. transport properties. Therefore, the water vapor transport
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F2298 − 03 (2009)
FIG. 1 Overview of the Test Methods
properties of the porous and non-porous textile materials test and generates data that allows direct comparison of the
cannotbedirectlycomparedwhenthemethodhasnoprovision
results obtained between materials.
for controlling the pressure gradient. This test method deter-
mines the diffusion and convection properties from the same
´1
F2298 − 03 (2009)
6. Sampling and Preparation of Test Specimens flows of a saturated and a dry nitrogen stream. The test
apparatus requires four mass flow controllers. Two controllers
6.1 Sampling:
adjustthedryandsaturatednitrogengasstreamstothetopflow
6.1.1 Laboratory Sample—Take test specimens that are
cell, and two controllers adjust the dry and wet nitrogen gas
believedtoberepresentativeofthesampletobetestedandfree
streamstothebottomflowcell.Themassflowcontrollersshall
ofabnormaldistortions.Thesamplemaybeapieceoffabricor
be controlled at an accuracy of 6 1% of full scale, with a
a garment.
response time of less than 5 s, unless stated otherwise in the
6.1.2 If the material is of nonsymmetrical construction, the
data report. Electronic mass flow controllers usually indicate
two faces shall be designated by distinguishing marks.
flow rate in terms of volumetric flow rates at standard
6.2 Sample Preparation:
conditions of 0°C and atmospheric pressure. The actual volu-
6.2.1 Cut three specimens from each laboratory sample.
metricflowrateattheactualtesttemperaturecanbecalculated
6.2.2 Specimen Size—Use specimens larger than the area of
from the mass flow rate, the temperature, and the pressure of
the opening in the clamping plate so that the test area is
the actual flow.
covered completely.
7.2.2 Channel Power Supply and Readout, controls and
displays the flow meters and controllers. The display accuracy
7. Test Apparatus
of the channel readout shall be within 6 0.2% 6 1 digit,
7.1 The procedures in these methods require measurement
unless stated otherwise in the data report.
ofthepressuregradientacrossthespecimenandthemassflow
7.2.3 Differential Pressure Transducer, directly measures
rate. Fig. 2 is a schematic diagram of the basic system for the
the pressure gradient across the specimen. The differential
dynamic moisture permeation cell (DMPC). This standard is
pressuretransducercanbeeitherdigitaloranalogtypewithan
written to allow operation of the DMPC system under manual
accuracy of within 6 0.2% of the indicated value. The sensor
control of the test operator. However, the preferred method is
requires power and signal conditioning electronics. The pres-
to automate the data acquisition and control system of the
sure in the flow cells is controlled by means of two automated
apparatus so the entire test is performed under the control of a
restrictor valves (7.2.5) at the outlets of the cell.
computer.
7.2.4 Signal Conditioner/Display Unit, provides power and
signal conditioning for the differential pressure transducer
7.2 Control and Measuring Units:
sensors.
7.2.1 Mass Flow Rate Controller,measuresandcontrolsthe
gas flows in a wide variety of applications. Either analog or 7.2.5 Proportioning Valve and Controller, used to continu-
electronic digital type mass flow rate controller can be used. ouslycontrolthegasflows.Therestrictorvalvesattheexitsof
The mass flow rate controllers maintain the correct incoming the cell are used to systematically vary the pressure gradient
relative humidity by adjusting the ratio of the relative mass across the specimen to produce various amounts of convective
FIG. 2 Schematic of DMPC Test System
´1
F2298 − 03 (2009)
flows across the specimen. The valves shall withstand the 7.3.1 Flow Cell Unit, consists of two identical flow cell
maximumpressureinthetestcellduringthetest.Insteadofthe segmentsmadeofplastic,glass,orothermaterialsthatwillnot
electronicpressuregaugesandautomatedrestrictorvalves,itis corrodeanddonotabsorbmoisture.Eachcellsegmentconsists
acceptable to use analog differential pressure gauges in a of a flow cell and a sample clamping plate.The size of the cell
variety of different full scale ranges, and manual needle or can be as large as practical, so as the size of the duct. The
orifice metering valves at the gas flow exit of the cells to typical size of the duct in each flow cell segment is 0.025 m
control the pressure gradient across the test specimen. wide, 0.13 m long, and 0.0050 m high. The entrance length of
7.2.6 Electronic Mass Flow Meter and Power Supply, con- the nitrogen gas must be long enough to get a stable fully
nects one of the exits of the flow cells (bottom cell) and the developed flow. At 2000 cm /min gas flow rate, more than
proportioning valve. The mass flow meter directly measures 0.002misrequiredfortheductlengthfromthegasentranceto
and displays the mass flow rate with a response time of within the sample, and from the specimen to the gas exit. The typical
5s. duct length is about 0.003 to 0.007 m. Each flow cell segment
7.2.7 Humidity Measurement Instrument,measurestherela- shall have ports for flow inlet and outlet in both ends of the
tive humidity of the incoming and the outgoing gas flows.The flow cell segment, and a port for differential pressure measure-
relativehumidityoftheincominggasflowisdirectlymeasured ment on the front top of the flow cell segment. A specimen is
with the humidity sensor. Relative humidity can be measured held in-between the two flow cell segments (Fig. 3).
in different ways, such as a condensation type dew point
7.3.2 Specimen Clamping Plate, can be made of plastic,
hygrometer, capacitance type relative humidity probe, or gas
metal, or steel, and attached to the flow cell segments by using
chromatography. Capacitance type humidity probe is recom-
a sealing agent or mounting bolts. The thickness of clamping
-5
mendedbecauseitprovidessmallsizeandafastresponsetime.
plate shall be5×10 m (0.5 mm). The hole opening in the
The relative humidity probes shall have a measurement accu-
clamping plate that determines the test area of the specimen
racy of 6 3% R.H. over the range in use, unless stated in the
shall have the size of 0.05 m long by 0.02 m wide (0.001 m ).
report.
Aspecimenmustbebiggerthantheholeofaclampingplateto
7.2.8 Temperature Measurement Instrument—The tempera-
cover the clamping plate completely.
ture measurement sensor shall measure the temperature within
7.3.3 Clamping System,preventsleakageofthenitrogengas
6 0.1°C with a time constant not exceeding 1 min. The
through the test cell unit. The sealing other than the clamping
temperature measurement shall be made at the same place as
force provided by the mounting bolts is unnecessary for most
the humidity measurement.
thinmaterialssuchaslaminatedandwoventextilematerials.If
7.3 Moisture Permeation Cell: there is any leakage from the edges of the specimen, special
FIG. 3 Typical Dimensions of the Specimen Holder for the DMPC
´1
F2298 − 03 (2009)
sealing methods such as molten wax, curable sealant, rubber valve or orifice, with a differential pressure sensor connected
sealing gaskets may be required. across the valve or orifice, which is connected to the output of
7.3.4 Bubblers, used to saturate nitrogen gas in water. a mass flow controller. Appropriate sizing of the needle valve
Bubblers of 500 mL or 1000 mL are appropriate for this test. or orifice opening, and the pressure transducer range, will give
The first bubbler completes the primary saturation of the gas a measured pressure gradient across the valve or orifice which
stream. The second bubbler ensures full saturation, and brings is indicative of whether each mass flow controller set at a
the gas stream back to deviation from the test temperature that particular flow is actually delivering identical gas flow rates.
may have occurred due to evaporative cooling in the first
8.3 Humidity Calibration—Requirements for humidity cali-
bubbler. The saturated and the dry nitrogen gas controlled by
bration will also depend on the humidity measurement system
separate mass flow meters shall merge into one gas tube and
selected for the test. Humidity calibration procedures may be
enter to the top flow cell. The ratio of dry and saturated
supplied by the manufacturer for the specific instrument, or
nitrogen gas determines the relative humidity in the flow cell.
may not be necessary for a high-accuracy system such as a gas
An identical set of two flow controllers and bubblers are
chromatograph, infrared diode laser sensor, or a chilled-mirror
neededtocontroltherelativehumidityofthebottomflowcell.
dew point hygrometer.
7.3.5 Data Acquisition System—It is possible to conduct the
8.4 Reference Material Calibration—Before starting test
tests manually by reading the outputs from the relative humid-
withaspecimen,conductatestwithareferencematerialunder
itymeasurementdevices,flowmeters,andpressuretransducers
the condition specified in 9.2. An expanded polytetrafluoreth-
and performing the necessary calculations. However, it is
ylene (ePTFE) film is used as a reference material for the
recommended to conduct the tests under the control of a
system. The ePTFE membranes are microporous and
computertoautomatethetasksofdatacollectionandcontrolof
hydrophobic, thus vapor transport takes place only through the
the mass flow controllers and valves.
interconnectedairspacesofthemembrane.Theydonotchange
7.4 Materials:
the transport properties as a function of membrane water
7.4.1 Reference Material, required for the calibration to
content or test conditions.
check the instrument before testing. Use microporous ex-
8.4.1 Test Conditions—Use the test conditions directed in
panded polytetrafluorethylene (ePTFE) membrane as a refer-
9.1.
ence material.
8.4.2 Place an ePTFE film in between the top and the
7.4.2 Nitrogen Gas, pure nitrogen gas with technical grade
bottom flow cell segments.
of 99% is used.
8.4.3 Follow the same procedures in 9.2.2 – 9.2.4.
8.4.4 Calculate total water vapor diffusion resistance Rdtot
8. Calibration Procedures
described in 9.3.
8.1 Threecalibrationproceduresmaybenecessary.Thefirst
8.4.5 The water vapor diffusion
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.