If unfamiliar with the material being tested, the operator should investigate the effect of conditioning time to be certain that sufficient time has been allowed for the material to equilibrate under the test conditions see Note 3. Key factors to understand material permeation include thickness of the material and environmental factors such as relative humidity and temperature. The method is applicable to sheets and? This is necessary only in the earlier model WVTR instruments that have a separate conditioning rack and testing chamber. This information is then used to calculate the rate at which moisture is transmitted through the material being tested. The accuracy of this method is therefore dependent upon the validity of the values assigned to these reference? F provides more precise and repeatable WVTR testing data compared to E96, and provides that information in less time. 
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ASTM F – pdf - ASTM F Standard Test Method for Water Vapor Transmission_百度文库
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. These entries should be rounded off to three signi? If the material is nonsymmetrical two sides differentinclude a statement as to which side was facing the high humidity, During testing, monitor the temperature, periodically, to the nearest 0. Due asgm the limitation of the sensitivity. F eliminates operator-dependent variables for more accurate test results, and enables more informed packaging decisions.
Your comments are invited either for revision of this standard or for additional standards and should be addressed to ASTM International Headquarters.
In earlier model WVTR equipment, a separate desiccant drying system is needed for the conditioning rack and test chamber. Packaging Applications - Industrial The lowest detection limit could be as low as 0. If unfamiliar with the material being tested, the operator should investigate the effect of conditioning time to be certain that sufficient time has been allowed for the material to equilibrate under the test conditions see Note 3. Send us a request Wilton UK: The method is applicable to sheets and?
Water Vapor Transmission Rate (WVTR) ASTM F1249
The test chamber shall incorporate means for clamping the diffusion cell in accurate registration with pneumatic system openings to the dry-air source and the infrared detector.
The value of C is derived from tests of a known reference? Originally approved in Your comments will receive careful consideration at a meeting of the responsible technical committee, which you may attend. These may be applied to both sides of a barrier to reduce the sample area.
This information is then used to calculate the rate at which moisture is transmitted through the material being tested. A typical acceptable diffusion cell area is 50 cm2.
It provides for the determination of 1 water vapor transmission rate WVTR2 the permeance of the film to water vapor, and 3 for homogeneous materials, water vapor permeability coefficient.
The chamber shall also provide a thermometer well for the measurement of temperature. Need help or have a question? Testing repeatability is of great importance. The method is applicable to sheets and films up to 3 mm 0. These shall incorporate O—rings suitable for sealing the diffusion cell to the test chamber pneumatic?
Assurance Testing Inspection Certification. Note 1 — Values for water vapor permeance and water vapor permeability must be used with caution. System Calibration With Reference Film 9.
Dry air is continually purging the dry chamber of those cells that are connected to the conditioning rack while the humid chamber side is held at a speci? Precision, characterized by repeatability Sr and r, and reproducibility SR and R, has been determined for the following materials to be: This is necessary only in the earlier model WVTR instruments that have a separate conditioning rack and testing chamber.
Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk of infringement of such rights, are entirely their own responsibility. By producing actionable results in less time, F accelerates product and packaging development, and time to market is similarly reduced.
The dry chamber and the d1249 chamber make up a 1. Test results from E96 method are also highly operator dependent.
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