BS EN ISO 3303‑2:2020 pdf – Rubber- or plastics-coated fabrics — Determination of bursting strength Part 2: Hydraulic method.
1 Scope This document specifies a method for the determination of the bursting strength of rubber – or plastics ‑ coated fabrics, using one of two types of diaphragm bursting tester, designated type A and B, both operated by hydraulic pressure. The type A test machine is applicable to materials having bursting strengths ranging from 350 kPa to 5 500 kPa and the type B test machine is applicable to materials of bursting strengths ranging from 70 kPa to 1 400 kPa. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 2231:1989, Rubber- or plastics-coated fabrics — Standard atmospheres for conditioning and testing 3? Terms? and? definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso.org/obp — IEC Electropedia: available at http://www.electropedia.org/ 4 Principle A test piece is securely clamped around its edges between an upper and lower clamp. A diaphragm fitted beneath the lower clamp is gradually stretched into a dome by forcing fluid at a constant rate into a chamber under the diaphragm, thus causing it to make contact with, and apply pressure to, the test piece. The pressure of the fluid and the height of the dome at failure of the test piece are recorded.
5.1.2 Type B test machine (see Figure 2), measurement range between 70 kPa and 1 400 kPa, comprising the elements specified in 220.127.116.11 to 18.104.22.168. 22.214.171.124 Clamping system, for clamping the test piece firmly and uniformly between two annular, plane, parallel surfaces which shall be smooth (but not polished) and grooved as described in Figure 2, which also gives the dimensions of the clamping system. One clamping plate shall be held in a swivel joint or similar device so as to ensure that the clamping pressure is distributed evenly. Under the load used for testing, the circular openings in the two clamping faces shall be concentric to within 0,25 mm and the clamping surfaces shall be flat and parallel. 126.96.36.199 Diaphragm, circular in shape, made of natural or synthetic rubber and 0,86 mm ± 0,06 mm thick, clamped securely, before the test begins, with its upper surface recessed about 3,5 mm relative to the upper surface of the lower clamp. The material and construction of the diaphragm shall be such that the pressure required to cause the diaphragm to bulge 9,0 mm ± 0,2 mm beyond the upper surface of the lower clamp is 30 kPa ± 5 kPa. Diaphragms in use shall be regularly checked and changed should the bulge‑height requirement be no longer met.6 Calibration Calibration shall be carried out in accordance with the test machine manufacturer’s manual before initial use and subsequently at sufficiently frequent intervals to maintain the specified accuracy. 7 Sampling The sample shall be taken so that it is as representative as possible of the whole consignment. 8 Preparation of test piece 8.1 Take five test pieces across the usable width of the sample (see NOTE), at least 1 m from the extremity of the sample, and of sufficient size so that each test piece can be clamped firmly in the clamping system of the test machine. The smaller dimension of each test piece shall be at least 12 mm greater than the outside diameter of the clamping surfaces. Alternatively, the sample may be tested at the requisite locations across its width, avoiding areas that have already been used for a test by at least 20 mm. NOTE The usable width is defined in ISO 2286‑1 as that width, excluding the selvedge, which is consistent in its properties, uniformly finished, and free of unacceptable flaws. 8.2 The face of the coated fabric to be tested shall be defined and agreed between the interested parties. The results might not be the same if the opposite face is tested. 8.3 When it is required to determine the properties of wet material, immerse the test pieces for 24 h in water (5.4), or water containing no more than 0,1 % wetting agent or surfactant (5.5), of about 20 times the total volume of the test pieces at the room temperature. Immediately after removal from the water, rinse thoroughly in water and proceed to test within 1 min.