ASTM F1307-02(2007)
(Test Method)Standard Test Method for Oxygen Transmission Rate Through Dry Packages Using a Coulometric Sensor
Standard Test Method for Oxygen Transmission Rate Through Dry Packages Using a Coulometric Sensor
SIGNIFICANCE AND USE
Oxygen gas transmission rate is an important determinant of the protection afforded by barrier materials. It is not, however, the sole determinant, and additional tests, based on experience, must be used to correlate package performance with O2GTR. This test method is suitable as a referee method of testing, provided that the user and source have agreed on sampling procedures, standardization procedures, test conditions, and acceptance criteria.
SCOPE
1.1 This test method covers a procedure for the determination of the steady-state rate of transmission of oxygen gas into packages. More specifically, the method is applicable to packages that in normal use will enclose a dry environment.
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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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation: F1307 − 02(Reapproved 2007)
Standard Test Method for
Oxygen Transmission Rate Through Dry Packages Using a
Coulometric Sensor
This standard is issued under the fixed designation F1307; 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.
3 3 −6
1. Scope cm (STP)/pkg·d,where1cm (STP)is44.62×10 mol,1atm
is 0.1013 mPa, and one day is 86 400 s.
1.1 This test method covers a procedure for the determina-
"
3.1.2 oxygen permeability coeffıcient (PO )—the product
tion of the steady-state rate of transmission of oxygen gas into
packages. More specifically, the method is applicable to of the permeance and thickness of the barrier.
packages that in normal use will enclose a dry environment. 3.1.2.1 Discussion—The permeability is meaningful only
for homogenous materials, in which case it is a property
1.2 This standard does not purport to address all of the
characteristic of the bulk material. This quantity should not be
safety concerns, if any, associated with its use. It is the
used unless the relationship between thickness and permeance
responsibility of the user of this standard to establish appro-
has been verified in tests using several thicknesses of the
priate safety and health practices and determine the applica-
material.TheSIunitofpermeabilityisthemol/m·s·Pa.Thetest
bility of regulatory limitations prior to use.
conditions must be stated.
'
2. Referenced Documents
3.1.3 oxygen permeance (PO )—the ratio of the O GTR to
2 2
the difference between the partial pressure of O on the two
2.1 ASTM Standards:
sides of the package wall.
D1434TestMethodforDeterminingGasPermeabilityChar-
3.1.3.1 Discussion—The SI unit of permeance is the mol/
acteristics of Plastic Film and Sheeting
D1898Practice for Sampling of Plastics (Withdrawn 1998) (pkg·s·Pa). The test conditions (see 4.2) must be stated.
D3985Test Method for Oxygen Gas Transmission Rate
Through Plastic Film and Sheeting Using a Coulometric 4. Summary of Test Method
Sensor
4.1 This test method employs a coulometric oxygen sensor
E691Practice for Conducting an Interlaboratory Study to
and associated equipment in an arrangement similar to that
Determine the Precision of a Test Method
describedinTestMethodD3985.Oxygengastransmissionrate
(O GTR)isdeterminedafterthepackagehasbeenmountedon
3. Terminology
a test fixture and has equilibrated in the test environment.
3.1 Definitions of Terms Specific to This Standard:
4.2 Thepackageismountedinsuchawayastoprovidethat
3.1.1 oxygen gas transmission rate (O GTR)—as applied to
the inside of the package is slowly purged by a stream of
a package, is the quantity of oxygen gas passing through the
nitrogen while the outside of the package is exposed to a
surface of the package per unit of time.
known concentration of oxygen. The package may be exposed
3.1.1.1 Discussion—The SI unit of transmission rate is the
in ambient room air which contains 20.8% oxygen, or im-
mol/pkg·s. The test conditions, including temperature, oxygen
mersed in an atmosphere of 100% oxygen.As oxygen perme-
partial pressure and humidity on both sides of the package,
ates through the package walls into the nitrogen carrier gas, it
must be stated. A commonly used unit of O GTR is the
is transported to the coulometric detector where it produces an
electricalcurrent,themagnitudeofwhichisproportionaltothe
ThistestmethodisunderthejurisdictionofASTMCommitteeF02onFlexible
amount of oxygen flowing into the detector per unit of time.
Barrier Packaging and is the direct responsibility of Subcommittee F02.10 on
Permeation.
5. Significance and Use
Current edition approved May 1, 2007. Published June 2007. Originally
approved in 1990. Last previous edition approved in 2002 as F1307–02. DOI:
5.1 Oxygen gas transmission rate is an important determi-
10.1520/F1307-02R07.
nant of the protection afforded by barrier materials. It is not,
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
however, the sole determinant, and additional tests, based on
Standards volume information, refer to the standard’s Document Summary page on
experience, must be used to correlate package performance
the ASTM website.
with O GTR. This test method is suitable as a referee method
The last approved version of this historical standard is referenced on 2
www.astm.org. of testing, provided that the user and source have agreed on
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1307 − 02 (2007)
7.1.2 Diffusion Cell, consisting of two metal halves which,
when closed upon the film used for system calibration, will
accurately define a circular area of that film. Typical diffusion
2 2
cell areas are 100 cm and 30 cm .The volumes inside the cell
above and below the enclosed film are not critical; they should
be small enough to allow for rapid gas exchange, but not so
small that an unsupported film which happens to sag or bulge
will contact the top or bottom of the cell. Means shall be
provided for the measurement of cell temperature.
7.1.2.1 O-Ring—An appropriately sized groove, machined
into the oxygen (or test gas) side of the diffusion cell, retains a
neoprene O-ring. The test area is considered to be the area
established by the inside contact diameter of the compressed
O-ring when the diffusion cell is clamped shut against the test
specimen.Thearea, A,canbeobtainedbymeasuringtheinside
diameteroftheimprintleftbytheO-ringonthespecimenafter
it has been removed from the diffusion cell.
7.1.2.2 Thenitrogen(orcarriergas)sideofthediffusioncell
shallhaveaflatraisedrim.Sincethisrimisthesealingsurface
against which the test specimen is pressed, it must be smooth
and flat, without scratches which may promote leakage.
7.1.2.3 Diffusion Cell Pneumatic Fittings—Each half of the
diffusion cell shall incorporate suitable fittings for the intro-
FIG. 1 Arrangement of Components when Reference Film is
duction and exhaust of gas without significant loss or leakage.
Used to Calibrate System for Package Testing
7.1.2.4 It is desirable to thermostatically control the diffu-
sion cell. A simple resistive heater, attached to the carrier gas
sampling procedures, standardization procedures, test condi-
side of the cell in such a manner as to ensure good thermal
tions, and acceptance criteria.
contact, is adequate for this purpose. A thermistor sensor and
an appropriate control circuit will serve to regulate the cell
6. Interferences
temperature unless measurements are being made close to
6.1 The presence of certain interfering substances in the
ambient temperature. In this case, it is desirable to provide
carrier gas stream may give rise to unwanted electrical outputs
cooling coils to remove some of the heat.
and error factors. Interfering substances include free chlorine
7.1.3 Catalyst Bed, a small metal tube with fittings for
and some strong oxidizing agents. Exposure to carbon dioxide
attachment to the inlet of the nitrogen gas pneumatic fitting
should also be minimized to avoid damage to the sensor
containing 3 to5gof0.5% platinum or palladium catalyst on
through reaction with the potassium hydroxide electrolyte.
alumina to provide an essentially oxygen-free carrier gas to
the diffusion cell and to each package test station.
7. Apparatus
7.1.4 Flowmeter, a flowmeter having an operating range of
7.1 Oxygen Gas Transmission Apparatus, as diagrammed
5 to 100 mL/min is required to monitor the flow rate of
in Fig. 1 with the following:
nitrogen carrier gas through each test station.
7.1.1 Package Test Stations, providing a means for the
7.1.5 Flow Switching Valves—Two or more valves for the
introduction and exhaust of the nitrogen carrier gas stream
switching of the nitrogen and test gas flow streams.
without significant loss or leakage.
7.1.6 Oxygen-Sensitive Coulometric Sensor, operating at an
7.1.1.1 Experience has shown that arrangements using mul-
essentially constant efficiency is employed to monitor the
tiple package test stations are a practical way to increase the
quantity of oxygen transmitted.
number of measurements that can be obtained from a coulo-
7.1.7 Load Resistor—The current generated by the coulo-
metric sensor.Avalving manifold connects the carrier gas side
metric cell shall pass through a resistive load across which the
of each individual test station to the sensor in a predetermined
outputvoltageismeasured.Typicalvaluesforloadresistorsare
pattern. Carrier gas is continually purging the carrier gas sides
5.3 ohm and 53 ohm. These values yield a convenient
of those packages that are not connected to the sensor. Either
relationship between the output voltage and the oxygen trans-
test gas (100% oxygen) or normal room air (20.8% oxygen),
mission rate as expressed in terms of cm (STP)/pkg·d.
whichever is appropriate, contacts the outside of the package.
4 5
The sole source of supply of the suitable apparatus, such as that embodied in The sole source of supply of a suitable catalyst known to the committee at this
several OXTRAN models, known to the committee at this time is available from time can be obtained from Englehard Industries Division, Chemical Dept., 429
Mocon Inc., 7500 BooneAve. North, Minneapolis, MN 55428. If you are aware of DelanceyStreet,Newark,NJ07105.Ifyouareawareofalternativesuppliers,please
alternative suppliers, please provide this information to ASTM International provide this information toASTM International Headquarters.Your comments will
Headquarters.Your comments will receive careful consideration at a meeting of the receive careful consideration at a meeting of the responsible technical committee ,
responsible technical committee , which you may attend. which you may attend.
F1307 − 02 (2007)
7.1.8 Voltage Recorder—The voltage across the load resis- 11. Test Specimens
tor is measured and recorded using a strip-chart potentiometer,
11.1 Test packages shall be representative of the population
data-logger or other suitable device. The instrument or system
and shall be free of non-typical defects.
should be able to measure a full-scale voltage of 50 mV. It
should be able to measure voltages as low as 0.10 mV with a
12. Calibration
resolution of at least 10 µV.An input impedance of 5000 ohm
12.1 General Approach—The oxygen sensor used in this
or higher is acceptable.
method is a coulometric device that yields a linear output as
predictedbyFaraday’sLaw.Sincethissensorhasanefficiency
8. Reagents and Materials
of 95 to 98% it is almost an absolute “yardstick” that does not
8.1 Nitrogen Carrier Gas, consisting of a nitrogen and
requirecalibration.Experiencehasshown,however,thatunder
hydrogen mixture in which the percentage of hydrogen shall
some circumstances the sensor may become depleted or
fall between 0.5 and 3.0 volume percent. The carrier gas shall
damaged to the extent that efficiency and response are im-
be dry and contain not more than 100 ppm of oxygen. A
paired. For this reason, the method incorporates means for
commercially available mixture known as “forming gas” is
periodic system calibration. This calibration is derived from
suitable.
measurements of a known-value “Reference Package.”
8.2 Sealing Grease—A high-viscosity silicone stopcock
12.2 Thereferencepackageisessentiallythelower-halfofa
grease or a high-vacuum grease is required for sealing the
diffusion cell (Fig. 1) in which a sheet of reference film of
calibration film in the diffusion cell.
known O GTR has been sealed and clamped. This creates a
8.3 Oxygen Test Gas—The test gas shall be dry and contain
“package” into which oxygen will diffuse at a known rate.
not less than 99.5% oxygen (except as provided for in 14.8).
12.3 Assembling the Reference Package—Ensure the sensor
isbypassedtoavoidswampingitwithair,thatis,noflowtothe
9. Technical Precautions
sensor. Unclamp the diffusion cell and open it. Apply a thin
9.1 Extendeduseofthetestunitwithnomoistureinthegas
layer of sealing grease (see 8.2) around the raised rim of the
stream may result in a noticeable decrease in output and
lower half of the diffusion cell. Insert the reference film in the
response time from the sensor (equivalent to an increase in the
diffusioncellandplaceituponthegreasedsurface,takingcare
calibrationfactor, Q).Thisconditionisduetodryingoutofthe
to avoid wrinkles or creases. Lower the upper half of the
sensor.
diffusioncellintoplaceandclampbothhalvestightlytogether.
9.2 Temperature is a critical parameter affecting the mea-
12.4 Purging the System—Startthenitrogencarriergasflow
surement of O GTR. Careful temperature control can help to
andpurgeairfromtheupperandlowerdiffusioncellchambers
minimize variations due to temperature fluctuations. During
using a flow rate of 50 to 60 cm /min (as indicated by the
testing,monitorandrecordthetemperature,periodically,tothe
flowmeter).After3or4min,reducetheflowratetothedesired
nearest0.5°C.Reporttheaveragetemperatureandtherangeof
value between 5 and 15 cm /min. Maintain this configuration
temperatures found during a test.
for 30 min.
9.3 Thesensorwillrequirearelativelylongtimetostabilize
12.5 Establishing Zero Level of Reference Film—After the
atalowreadingcharacteristicofagoodbarrierafterithasbeen
system has been flushed with nitrogen for 30 min, with the
usedtotestabarriersuchaslow-densitypolyethylene.Forthis
sensor bypassed, divert the nitrogen carrier gas flow to the
reason, materials of comparable gas transmission qualities
sensor. At this time the sensor output, as displayed on the
should be tested together.
voltage recorder, will usually increase abruptly, indicating that
oxygen is entering the sensor with the carrier gas. The most
9.4 Back diffusion of air into the unit is undesirable. Take
likely sources of this oxygen are (1) outgassing of the sample,
care, therefore, to ensure that there is a flow of nitrogen
(2)leaksinthesystem,or(3)acombinationof(1)and(2).The
through the system at all times.This flow can be low when the
operatorshallobservetherecordertraceuntilthesensoroutput
instrument is not being used.
current stabilizes at a constant low value with no significant
9.5 The gas-permeability characteristics of some barrier
trend in either direction. Note the observed deflection of the
materials are altered by exposure to water vapor. If a package
strip chart recorder at this time and label it E .
is to be exposed and tested in normal laboratory air (20.8%
O ), the ambient relative humidity should be monitor
...
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