ASTM D737 textiles air permeability test method analys

What is air permeability? The air permeability is the volume of air passing a fabric under pressure. There are two types of air permeability tester for textiles, Frazier air permeability tester and Shirley air permeability tester. In ASTM D737 test method, we take Frazier air permeability tester as example.

 

To determine the air permeability of textile fabrics by calculating the air permeability value.

 

Woven, knitted and non woven textile materials. eg.  cotton.

 

1、The specimens must be adjusted to the standard atmosphere with  21 +/- 1°C (70 +/- 2°F) and 65 +/- 2 % relative humidity unless there is otherwise specification of contract order.

2、Process the specimens carefully and prevent it from changing its’ natural state.

3、Place each specimen on the test head of the air permeability tester, and control the test as the operation manual.

4、At the conditioned water pressure, making tests accord to the operation manual. In the absence of an operation manual, use a water pressure 125 Pa (12.7mm or 0.5 in. of water).

5、Read and record the test results. The air permeability units should be noted. Record the test results respectively in SI units as cm^3/s/cm^2 and in inch-pound units as ft^3/min/ft^2 rounded to three significant digits.

6、Take out the tested specimen and continue to test next specimen until the ten specimens have been tested in accordance with the flow of 4.3-4.5.

7、In order to make sure a high accuracy, the number of test is at least four.

 

1、Calculate air permeability of every specimen by reading directly from the tester in SI units as cm^3/s/cm^2 and in inch-pound units as ft^3/min/ft^2, rounded to three significant digits. Please follow the instructions which the manufacturer provides when calculating air permeability.

Note-If air permeability results are 600m (2000 ft) above the sea level, it needs correction factors.

2、When data are calculated by computer automatically, the calculation is included in the software. Therefore, it is suggested to verify against the known values and the description of the software which is used in the test.

 

The data which is needed to report is as follows.

1、Report whether the air permeability is in accordance with the Test Method D737.

2、Report the standard deviation and the variation factor while calculating.

3、The difference in pressure of fabric surfaces.

4、Report the model and the manufacturer of the air permeability test equipment.