ASTM D2061-07(R2021) pdf free download

ASTM D2061-07(R2021) pdf free download.Standard Test Methods for Strength Tests for Zippers
4. Significance and Use
4.1 The usefulness ofa zipper in service can be evaluated by these tests. No one test determines the suitability ofa zipper for a specific end use. Since the tests are inter-related more than one may be needed for a complete evaluation. 4.2 These methods are considered satisfactory for accep- tance testing of commercial shipments because the methods have been used extensively in the trade for this purpose, and because estimates of current between-laboratory precision are acceptable in most cases. 4.2.1 If there are differences of practical significance be- tween reported test results for two laboratories (or more), comparative test should be performed to determine if there is a statistical bias between them, using competent statistical assis- tance. As a minimum, the test samples should be used that are as homogeneous as possible, that are drawn from the material from which the disparate test results were obtained, and that are randomly assigned in equal numbers to each laboratory for testing. Other materials with established test values may be used for this purpose. The test results from the two laboratories should be compared using a statistical test for unpaired data, at a probability level chosen prior to the testing series. If a bias is found, either its cause must be found and corrected, or future test results must be adjusted in consideration of the known bias. 4.3 The method(s) in the standard along with those in Test Methods D2051, D2052, D2053, D2054, D2057, D2058, D2059/D2059M, D2060, and D2062 are a collection ofproven test methods. They can be used as aids in the evaluation of zippers without the need for a thorough knowledge of zippers. The enumerated test methods do not provide for the evaluation of all zipper properties. Besides those properties measured by means of the enumerated test methods there are other proper- ties that may be important for the satisfactory performance of a zipper. Test methods for measuring those properties have not been published either because no practical methods have yet been developed or because a valid evaluation of the informa- tion resulting from existing unpublished methods requires an intimate and thorough knowledge of zippers.
5. Sampling
5.1 Lot Sample—As a lot sample for acceptance testing, take at random the number of individual containers from each shipping carton as directed in an applicable material specifi- cation or other agreement between the purchaser and the supplier. Consider individual containers from each shipping carton to be the primary sampling units. N OTE 1—An adequate specification or other agreement between the purchaser and supplier requires taking into account the variability between shipping cartons and between zippers in a container to provide a sampling plan with a meaningful producer’s risk, consumer’s risk, acceptable quality level, and limiting quality level. 5.2 Laboratory Sample and Test Specimens—As a labora- tory sample for acceptance testing, take the number of zippers specified in Section 6 at random from each container in the lot sample. Consider the zippers as both the laboratory sample and the test specimens.
6. Number of Specimens
6.1 Variables—Take a number of zippers per individual container from each shipping carton such that the user may expect at the 90 % probability level that the test result for an individual container is no more than 10 % of the average, above or below the true average for the individual container. Determine the number of zippers per individual container as follows:6.1.1 Reliable Estimate of v—When there is a reliable estimate of v based upon extensive past records for similar materials tested in the users laboratory as directed in the method, calculate n using Eq 1.