ASTM D726 Standard Test Method for the Resistance of Paper to Air Passage

Developed by the American Test and Materials Association (ASTM), the ASTM D726 standard includes a test method for determining the resistance of non-porous paper to air passage. This test method can be applied to papers that allow a passage of up to 15 ml of air in 25 seconds, and papers that are generally not sufficiently porous to be tested with TAPPI methods T460 and T536. TAPPI T460 and T536 are standards used to test bulk and semi-solid papers. Since these three methods (ie D726, T460 and T536) do not yield the same results, it is recommended that the specifications for the papers be agreed between the parties on a particular method and that the method is chosen to be appropriate. The full name of this standard is as follows: ASTM D726 Standard test method for the resistance of non-porous paper to air passage.

The test method presented, by the way, does not claim to address all of them if there are safety concerns for use. It is the sole responsibility of those applying this standard to establish appropriate safety and health practices and to determine the applicability of regulatory restrictions prior to use.

The test method described in the ASTM D726 standard involves determining the resistance of non-porous paper to air passage. This method cannot be used in situations where the paper cannot be securely clamped against surface and edge leakage, such as crepe or corrugated papers.

TAPPI (Pulp and Paper Industry Technical Association) standards are developed to measure, evaluate and describe paper and pulp products. These standards are also applied to raw materials used in production activities and scientific research.

TAPPI T460 Paper air resistance (Gurley method) is used to measure the air resistance of a circular paper area of ​​approximately 1,22 cm6,45 using a pressure difference of 2 kPa. The recommended interval of the liquid column apparatus is 100 to 5 seconds per 1800 ml cylinder displacement. The time requirements for more impermeable papers are so high that other techniques are preferred. This method measures the volume of air passing through the test sample with possible air leakage across the surface. Therefore, it is not suitable for paper or cardboard that cannot be securely clamped to prevent significant surface or edge leakage.

TAPPI T536 The resistance of the paper to air passage (high pressure Gurley method) is used to measure the air resistance of the circular paper area of ​​approximately 3 cm6,4 using a pressure difference of approximately 2 kPa. The recommended range of this device is for paper that requires 10 or more seconds for 10 ml of air to flow. Other techniques are preferred for more permeable papers. This method measures possible air leakage across the surface, along with the time it takes for a given volume of air to pass through the test sample. Therefore, it is not suitable for rough surfaced paper that cannot be securely clamped to prevent significant surface and edge leakage.

In the application of the ASTM D726 standard, it can be used as an indirect indicator of variables such as weather resistance, degree of impact, absorbency (oil and water penetration), apparent specific gravity, filtering efficiency for liquids or gases, and so on. It is affected by both the internal structure and the surface coating. The internal structure is largely controlled by the type and length of the fiber, the degree of hydration, orientation, and compression. The surface finish is determined by the degree of wet pressing, the types of felt used in production, and primarily by the presence or absence of calendering and coating.

Our organization, among numerous testing, measurement, analysis and evaluation studies, with its trained and expert staff and advanced technological equipment, within the framework of national and international standards, provides standard test services for the resistance of non-porous paper to air passage within the scope of ASTM D726 standard.