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Standards Governing Gas Permeability Test Explained

Standards Governing Gas Permeability Test Explained
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Standards Governing Gas Permeability Test Explained - 1

Labthink Instruments Co., Ltd. info@labthink.com +86-531-85068566 Standards Governing Gas Permeability Test Explained Gas permeability is a critical property for various materials, influencing applications ranging from food packaging to medical devices. Accurate and consistent measurement of this property is essential. International and domestic standards governing gas permeability testing show inconsistencies which may lead to confusion when interpreting data and comparing results across different studies. Labthink C130H Gas Permeability Tester is based on manometric method and conforms to ASTM D1434, while C206H Oxygen Transmission Rate Test System is based on the coulometric sensor method and conforms to ASTM D3985 Two primary methods are employed for gas permeability measurement: the manometric method and the equal pressure method. Each method utilizes a specific terminology for related concepts. Here's a breakdown of the key parameters: Gas Transmission Rate (GTR): This reflects the volume of gas permeating a material unit area per unit time. While seemingly simple, GTR is highly dependent on test conditions, particularly the pressure differential between the material's two sides. This dependence makes GTR less suitable for data comparison across studies. Permeance: This parameter represents a material's inherent property, independent of test conditions. It quantifies the ease with which gas flows through the material under a specific pressure difference. Permeance is generally considered the most valuable parameter for material comparison. Permeability Coefficient: This combines permeance with the material's thickness, providing a property specific to the material itself. 1

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Standards Governing Gas Permeability Test Explained - 2

Labthink Instruments Co., Ltd. info@labthink.com +86-531-85068566 The following table summarizes the terminology variations between standards for the manometric and equal pressure methods: The key takeaway is that permeance offers the most reliable parameter for material comparison due to its independence from test conditions. Gas transmission rate, while seemingly straightforward, can be misleading due to its dependence on pressure differentials. Additionally, the report emphasizes that GTR may not be suitable for all materials, particularly those with multilayers. Understanding the...

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