Application
The Computerized Air Permeability Tester is designed to measure the resistance of various fabrics — including woven, knitted, and non-woven textile materials — to air passage under a constant pre-set air pressure. This device ensures accurate testing by firmly clamping the specimen in the test rig of the selected test head/area.
Equipped with a pneumatic holder, the specimen is easily secured, and testing begins with a simple press of the holder. The tester uses a vacuum pump to draw air through an automatically interchangeable test head with a circular opening. Pre-selected test pressure is automatically maintained, and within seconds, air permeability results are displayed digitally on an LCD screen or a connected computer (not included). Once the test concludes, the holder releases, and the vacuum pump shuts off.
Testing Method
Testing Method: Frazier Air Permeability Test (ASTM D737)
- Air Permeability Definition Air permeability measures the volume of air that passes through a fabric under controlled pressure conditions. The Frazier differential pressure air permeability tester, used in the ASTM D737 method, is one of the standard devices for this type of testing.
- Test Objectives To determine the air permeability of textile fabrics by calculating the air permeability value.
- Applicable Materials Suitable for woven, knitted, and non-woven textile materials (e.g., cotton).
- Air Permeability Test Procedure 4.1 Condition specimens to a standard atmosphere of 21 ± 1°C (70 ± 2°F) and 65 ± 2% relative humidity unless otherwise specified. 4.2 Handle specimens carefully to preserve their natural state. 4.3 Secure the specimen onto the test head of the air permeability tester. 4.4 Conduct tests at a standard water pressure of 125 Pa (12.7 mm or 0.5 in. of water) unless specified otherwise. 4.5 Record results in SI units (cm³/s/cm²) or inch-pound units (ft³/min/ft²), rounded to three significant digits. 4.6 Repeat steps 4.3 to 4.5 for ten specimens. 4.7 Ensure at least four tests are conducted for high accuracy.
- Air Permeability Calculation 5.1 Calculate air permeability directly from the tester readings in specified units. 5.2 When using computer software for calculations, verify results against known values.
- Test Report 6.1 Confirm compliance with ASTM D737. 6.2 Report standard deviation and variation factors. 6.3 Document the pressure differential across fabric surfaces. 6.4 Specify the model and manufacturer of the air permeability testing equipment.
Important Considerations
- Calibrate the device before each test.
- Ensure samples are fixed naturally and smoothly on the intake hole.
- Select the appropriate caliber size for accurate readings.
- Adjust pressure slowly to avoid exceeding constant pressure value.
- Confirm the pressure gauge is unobstructed for proper atmospheric passage.
- Understand the non-linear relationship between air permeability and differential pressure.
- Account for unit conversion between different air permeability measurements.
