ASTM D737: Air Permeability Testing machine for Textile Fabrics

ASTM D737 is a test standard that specifies the method for measuring the air permeability of textile fabrics.The test method described in ASTM D737 provides a quick, simple and reliable method for determining the air permeability of textile fabrics.

The purpose of the test is to determine the ease with which air can pass through the fabric and to provide a measure of its breathability. The test is typically performed on fabrics used for clothing, curtains, upholstery and other similar applications.

The testing equipment for ASTM D737 typically consists of a calibrated air flow apparatus, a sample clamping device and a means of measuring air flow. The test involves clamping a test specific of the fabric over a circular opening in the apparatus and measuring the rate of air flow through the fabric.

The result is expressed as the cubic feet of air per minute (CFM) that passes through a square foot of fabric.

The air permeability of the fabric is determined by comparing the test results to a standard reference fabric or by conducting multiple tests under different pressure conditions.

How is Air Permeability in Textile Measured?

Textile air permeability measurement is calculated using three main principles and units. Instruments are designed separately based on those principles. Each instrument operates on different parameters.

1. Gurley Tester

2. Frazier Tester

3. Shirley Air Permeability Tester

Gurley Tester

The tester is designed based on the time taken by the specific volume of air to pass through the fabric under constant pressure. It is used for low-permeability textiles, such as windproof, waterproof, and weatherproof garments.

Frazier Tester

This tester is designed based on the velocity of air passing through the fabric under a constant pressure drop. It focuses on how easily air can pass through the specimen. This tester is applied to high-air permeability textiles, such as outdoor garments and clothing.

Shirley Air Permeability Tester

This instrument determines the air permeability of a wide range of textiles. It is used for both woven and non-woven fabrics. This tester works on the principle of measurement of pressure differences against specimens.

1. Conditioning of Test Specimen

The textile sample used to evaluate air permeability should be conditioned 24 hours before the test in the textile lab. It should be placed at 20 + 2 C, with a relative humidity level of 65%.

Improper conditioning at different temperatures and humidity levels may lead to variation in results.

2. Cut & Place the Specimen on the Tester

Cut the fabric sample long enough to place it easily on the tester. The sample can be taken in a square shape, like A4-size paper, or a circular shape, like GSM.

The specimen should be neat and clean, without contamination, crease and wrinkle-free. It is mounted on the Frazier air permeability tester under a circular clamp.

The clamp holds the specimen tightly. During mounting, the specimen should not be too stretched or under tension.

UnitedTest UT4070A and UT4070B is suitable for this kind of test.