Meaning and use
5.1 The results of this test method will indicate the relative water permeability of the tape at the smallest size, usually perpendicular to the backing of the tape.

5.1.1 The water channel parallel to the interface of the tape cup is much larger than the thickness of the tape cup, which is usually an almost separate transmission water source.

5.1.2 Some types of tape allow a relatively free path in a direction perpendicular to the backing or along a backing path parallel to the glue cup interface, thus making the adhesive the primary barrier.

5.2 If the adhesive does not continue to adhere to the cup body flange during exposure, resulting in an unexpected water intake path, it shall be considered that no measurement has been made. Therefore, in wet conditions (close to test conditions), tape may not be suitable for use on surfaces such as cup flanges.

Note 1: It may only be the use of tape material as a waterproof material that has aroused interest. In this case, the degree to which the tape adheres to the cup flange may not matter, and measures need to be taken to prevent any edge effects. These will be mentioned in section 10.

ASTM D3816/D3816M-2020 “Standard Test Method for Water Permeability of Pressure Sensitive Tape”

Step 1: Scope
1.1 The test method provides a procedure for measuring 2-inch water permeability. Or wider pressure-sensitive tape.

1.2 Values expressed in SI units or inch-pound units shall be regarded as standard values respectively. The values specified in each system may not be equal; Therefore, each system needs to be used independently and the values cannot be combined in any way.

1.3 This standard is not intended to address all safety concerns associated with its use. It is the responsibility of users of this standard to establish appropriate safety, health and environmental specifications and to determine the applicability of regulatory restrictions prior to use.

1.4 This international standard is based on internationally recognized standardization principles established in the Decision on Principles for the Development of International Standards, Guidelines and Recommendations issued by the WTO Technical Barriers to Trade (TBT) Committee.

2. Refer to the file
ASTM standard

D996 Packaging and distribution environmental terms

D3715 / D3715M pressure sensitive tape quality assurance practice

D4332 Practice of regulating containers, packaging or packaging components for testing

E122 Practice of calculating sample sizes to estimate average values of batch or process features with specified precision