Fabric air permeability refers to the existence of a pressure difference between the two sides of the fabric, the fabric through the performance of air, that is, the two sides of the fabric in the specified pressure difference, the volume of air flowing through the unit area of the fabric in a unit of time.
Air permeability will affect the human body’s surface and clothing microclimate zone; this microclimate directly affects the human body’s comfort feelings.
For example, general clothing is required to cool through, not be stuffy; this microclimate should be exchanged with the outside world air, conducive to the dissipation of body heat, so the requirements of the fabric should have a certain degree of breathability; and winter clothing requirements for warmth, which will have to ask for the microclimate as stable as possible in order to reduce the loss of human body heat, at this point we need to clothing windproof, that is, the breathability to be small.
So for taking products, the size of the breathability is an important performance it can not be ignored.
Table of Contents
Testing Principles
The test principle of air permeability is to measure the airflow through a given area of the specimen vertically for a certain period of time under the specified differential pressure conditions and calculate the air permeability rate.
Test Standards
At present, the commonly used air permeability test methods at home and abroad are GB/T 5453-1997 “Determination of Air Permeability of Textile Fabrics,” ISO 9237:1995 “Determination of Air Permeability of Textile Fabrics”, ASTM D737-2018 “Test Methods for the Air Permeability of Textile Fabrics” and so on.
Influencing factors of air permeability
There are many factors affecting the air permeability of fabrics, excluding external factors such as temperature and humidity and the gas pressure difference between the two sides of the fabric; the internal factors of the fabric itself are mainly closely related to the inter-fiber gap degree.
For example, with the same organizational structure, natural fiber fabrics are generally better than chemical fiber fabrics; this is because the natural fiber cross-section of irregular morphology, fiber fineness is not uniform, in the spinning of yarn, between the fibers are prone to pores; the same kind of fibers, fabrics, fabrics, organizational structure is the main factor affecting its permeability, such as the general speaking permeability satin fabrics> twill fabrics> plain fabrics, fluffy, thin, thin permeable fabrics than tight, thick, thick fabrics.
Fabric permeability is greater than tight, heavy fabrics, etc.; the fabric finishing process is another major factor affecting the permeability, such as the same kind of blank fabrics and its finishing process and processing conditions will affect the degree of elasticity of the fabric and the surface morphology, thus affecting the permeability of the sand washing, stone grinding, milling, washing, etc.
After finishing, the surface fluff increase or yarn tightness will increase the decrease in the permeability of the fabric; and the three anti-deterioration finishing, Functional finishing, coating, laminating, composite, and other finishing processes, the gap in the fabric will be further bridged, or even the formation of the airtight film, the fabric air permeability will drop sharply.
Test Apparatus
AirFicient Air Permeability Tester is suitable for a variety of textiles, including technical fabrics, non-woven fabrics, and other breathable products such as sponges and paper, and other materials for air permeability testing.
The principle is that the air passes vertically through the fabric, forming a certain pressure difference between the front and back sides of the fabric, measuring the amount of air flowing through the fabric unit area per unit of time under a certain pressure difference, thus obtaining the air permeability value.
The air permeability of textile fabrics plays a significant role in determining their functionality and comfort. For example, in the apparel industry, the breathability of clothing affects the wearer’s comfort by allowing moisture vapor to escape, reducing the feeling of wetness.
Similarly, in the automotive and aerospace sectors, air permeability influences factors such as seat cover comfort, ventilation, and cabin air quality. In filtration applications, the air permeability of fabrics is crucial for ensuring efficient air or liquid filtration.
Conclusion
The determination of air permeability in textile fabrics is a critical aspect of fabric characterization. It provides valuable insights into the performance, functionality, and comfort properties of fabrics.
The Gurley method and the Shirley air permeability tester are commonly used techniques to measure air absorptivity. By understanding the air permeability of fabrics, manufacturers can make informed decisions about material selection and tailor fabrics to meet specific application requirements.
Specification of AirFicient Air Permeability Tester
Measurement units mm/s m/s l/m²/s ft³/min/ft² cfm
cm³/s/cm² l/s/cm² l/m²/min l/dm²/min l/min m³/min dm³/s
m³/s/m² m³/min/m² m³/h/m² ft³/s/ft²
Test Mode Automatic
Test head 20 cm2 (standard)
Test pressure 10 ~ 2,500 Pa
Air velocity 0.6 ~ 10,000 mm/s (20 cm2)
Maximum sample thickness 0 ~ 10 mm
Testing Accuracy <+/-2%
Optional test heads 5 cm2, 25 cm2, 38 cm2, 50 cm2, 100 cm2
Power 230V 50/60Hz 8A
Weight 125kg
Dimension
970*400*970 mm (D*W*H)
