ISO 6801:2021 pdf download – Rubber and plastics hoses — Determination of volumetric expansion.
1 Scope This document specifies a method for the determination of the volumetric expansion of rubber or plastics hoses under hydrostatic pressure. This document does not specify the dimensions of the test piece and the test pressure(s) as each of which is specified in the appropriate specification. 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 1402, Rubber and plastics hoses and hose assemblies — Hydrostatic testing ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 8330 apply. ISO and IEC maintain terminology databases for use in standardization at the following addresses: — ISO Online browsing platform: available at https://www.iso .org/obp — IEC Electropedia: available at https://www.electropedia .org/ 4 Apparatus 4.1 See Figure 1 . The apparatus comprises a suitable source of fluid which can be maintained at the required pressure, together with pressure gauges, piping, valves and fittings, so that a vertical length of hose can be subjected to hydraulic pressure. A graduated burette of sufficient accuracy is also required for measuring the volume of fluid corresponding to the expansion of the hose under pressure. 4.2 The bore of all piping and connections shall be smooth without recesses or off-sets, so that all air can be freely removed from the system before carrying out each test. The valves shall be of such design as to open and close with minimum displacement of fluid. The apparatus shall be capable of increasing the pressure in the test piece in accordance with ISO 1402. The rate of pressure increase shall be a) between 0,075 MPa/s and 0,175 MPa/s for test pressures up to and including 12,5 MPa, and b) between 0,35 MPa/s and 1,0 MPa/s for higher test pressures.
6 Procedure 6.1 Carefully connect the test piece in position on the apparatus in such a way as to obtain a leak- proof seal, taking care to avoid twisting it. Maintain the test piece in a vertical position without being in tension while under pressure. The free length of the test piece should be measured. 6.2 Fill the tank (1) with distilled water, taking care that it is free of air or dissolved gases. Open valve A (2) and fill the pressure source (4) with liquid. Open valve B (5) and partially open valve C (7) and allow the liquid to run from the tank through the burette (8) until no air bubbles are seen in the burette. NOTE Removal of air bubbles can be facilitated by moving the test piece back and forth. 6.3 Close valve A (2), C (7) and D (9) and raise the pressure in the test piece (6) to the test pressure and maintain for 10 s. Check for leaks at the connections and release the pressure completely in the test piece by opening valve C (7), which shall then be closed before proceeding as described in 6.4 . 6.4 Adjust the liquid level in the burette to the zero mark by means of valve D (9).
ISO 6801:2021 pdf download – Rubber and plastics hoses — Determination of volumetric expansion
