ASTM E2945-14

Standard Test Method for Film Permeability Determination Using Static Permeability Cells

SIGNIFICANCE AND USE
5.1 This test method provides a simple approach for determining the transmission properties of film membranes and sheeting over a range of permeability exceeding four orders of magnitude. This test method is described here to measure the permeability of films used in soil fumigation, but it is also appropriate for other gases and membranes if the analytical methods are appropriately modified.  
5.2 This test method can be used for single or mixed compounds. This test method uses small quantities of test chemicals in vapor form, and microgram to milligram quantities of each chemical may produce a sufficient amount of vapor for each test depending on the analytical methods.  
5.3 Interlaboratory testing showed that the MTC estimated by this test method is relatively insensitive to the laboratory procedures. The interlaboratory testing involved measuring the MTC for several soil fumigant compounds and a wide range of film permeability. Analysts with prior experience handling and analyzing gaseous fumigant compounds had lower coefficients of variation (10 to 20 %) compared to less experienced analysts (20 to 50 %) based on triplicate tests. The coefficient of variation between laboratories was higher for less permeable film materials than for films with high MTC. This was attributed to the additional length of the experiments and potential for increased leakage from the apparatus and was most pronounced for less experienced analysts.
SCOPE
1.1 This test method covers the measurement of the transmission of a gas through plastic membranes, sheeting, films, and fabric materials using a static sealed diffusion chamber. The test method monitors gas diffusion across a film membrane and provides measurements of (1) gas concentrations on each side of the film membrane and (2) estimates of the mass transfer coefficient (MTC) for the tested gas and film material. The MTC represents the film permeability and is independent of the concentration gradient used during testing, which simplifies some aspects of the experimental design.  
1.2 This test method permits the loading of mixed vapors and simultaneous determination of the permeability of one film to various gases.  
1.3 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.  
1.4 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-Jan-2014
• ICS: 83.140.10 - Films and sheets
• Technical Committee: E35 - Pesticides, Antimicrobials, and Alternative Control Agents
• Drafting Committee: E35.22 - Pesticide Formulations and Delivery Systems

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: E2945 − 14
Standard Test Method for
Film Permeability Determination Using Static Permeability
1
Cells
This standard is issued under the fixed designation E2945; 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.
1. Scope 3. Terminology
3.1 Definitions:
1.1 This test method covers the measurement of the trans-
mission of a gas through plastic membranes, sheeting, films,
3.1.1 concentration, C, n—chemical mass divided by the
and fabric materials using a static sealed diffusion chamber. chamber volume.
Thetestmethodmonitorsgasdiffusionacrossafilmmembrane
3.1.1.1 Discussion—C is the initial (t = 0) concentration in
o
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and provides measurements of (1) gas concentrations on each
the source chamber. The SI unit of concentration is µg/cm .
side of the film membrane and (2) estimates of the mass
3.1.2 concentration gradient, n—difference in the concen-
transfer coefficient (MTC) for the tested gas and film material.
tration of gases across the film membrane divided by the
The MTC represents the film permeability and is independent
transport distance between the source and collection chambers
of the concentration gradient used during testing, which
(for example, usually considered to be the film thickness).
simplifies some aspects of the experimental design.
3.1.2.1 Discussion—The SI unit of the concentration gradi-
3
1.2 This test method permits the loading of mixed vapors
ent is µg/cm -cm.
andsimultaneousdeterminationofthepermeabilityofonefilm
3.1.3 mass transfer coeffıcient, MTC, n—gas diffusion rate
to various gases.
constant that relates the mass transfer rate, distance, and
1.3 Units—The values stated in SI units are to be regarded concentration gradient as the driving force through a film
membrane under the test conditions.
as the standard. No other units of measurement are included in
this standard. 3.1.3.1 Discussion—TheSIunitoftheMTCiscm/hour.The
MTC expresses the ease of transmission of a gas through a
1.4 This standard does not purport to address all of the
membrane under test conditions. The test conditions shall be
safety concerns, if any, associated with its use. It is the
stated, which include the ambient temperature, relative
responsibility of the user of this standard to establish appro-
humidity, film conditioning, sampling, and handling.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. 3.1.4 mass transfer rate, J, n—mass transfer rate, or flux
density,ofagasdiffusingthroughafilmmembraneisthemass
2
of gas passing through a unit area (for example, 1 cm)offilm
2. Referenced Documents
2 membraneperunittimeinterval(forexample,1h).TheSIunit
2.1 ASTM Standards:
2
of J is µg/cm hour.
D618Practice for Conditioning Plastics for Testing
3
D1898Practice for Sampling of Plastics (Withdrawn 1998)
4. Summary of Test Method
E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method 4.1 This test method uses a static sealed apparatus consist-
ing of two chambers separated by the test-film membrane.The
testchemicalinthevaporphaseisaddedtothechamberonone
side of the film and the apparatus is incubated at constant
1
This test method is under the jurisdiction of ASTM Committee E35 on
temperature during which the chemical diffuses through the
Pesticides, Antimicrobials, and Alternative Control Agents and is the direct
responsibility of Subcommittee E35.22 on Pesticide Formulations and Delivery
test membrane. This test method requires determination of the
Systems.
relative chemical concentrations on both sides of the mem-
Current edition approved Feb. 1, 2014. Published April 2014. DOI: 10.1520/
brane at several time points during the incubation. Concentra-
E2945-14.
2
tions are monitored until equilibrium is reached or some other
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
practical stoppage time. For permeable films, more frequent
Standards volume information, refer to the standard’s Document Summary page on
sampling is necessary because equilibrium may be reached
the ASTM website.
3
within minutes or hours. For films with very low permeability,
The last approved version of this historical standard is referenced on
www.astm.org. longer incubation times (weeks) may be necessary to reach
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E2945 − 14
FIG. 1 Schematic of Static Film Permeability Apparatus
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