BS EN ISO 3949-2020 pdf – Plastics hoses and hose assemblies – Textile-reinforced types for hydraulic applications – Specification

BS EN ISO 3949-2020 pdf – Plastics hoses and hose assemblies – Textile-reinforced types for hydraulic applications – Specification.
1 Scope This document specifies requirements for three types of textile-reinforced thermoplastics hoses and hose assemblies of nominal size from 3,2 to 25. Each type is divided into two classes dependent on electrical conductivity requirements. They are suitable for use with: — oil-based hydraulic fluids HH, HL, HM, HR and HV as defined in ISO 6743-4 at temperatures ranging from −40 °C to +93 °C; — water-based fluids HFC, HFAE, HFAS and HFB as defined in ISO 6743-4 at temperatures ranging from 0 °C to +60 °C — water at temperatures ranging from 0 °C to +60 °C. This document does not include any requirements for end fittings. It is limited to the performance of hoses and hose assemblies. NOTE It is the responsibility of the user, in consultation with the hose manufacturer, to establish the compatibility of the hose with the fluid to be used. 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 1817, Rubber, vulcanized or thermoplastic — Determination of the effect of liquids ISO 4671, Rubber and plastics hoses and hose assemblies — Methods of measurement of the dimensions of hoses and the lengths of hose assemblies
ISO 6803, Rubber or plastics hoses and hose assemblies — Hydraulic-pressure impulse test without flexing ISO 7326:2016, Rubber and plastics hoses — Assessment of ozone resistance under static conditions ISO 8330, Rubber and plastics hoses and hose assemblies — Vocabulary ISO 10619-1:2017, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness — Part 1: Bending tests at ambient temperature ISO 10619-2:2017, Rubber and plastics hoses and tubing — Measurement of flexibility and stiffness — Part 2: Bending tests at sub-ambient temperatures ISO 17165-1, Hydraulic fluid power — Hose assemblies — Part 1: Dimensions and requirements
3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 8330 apply. 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 Classification Three types of hoses are specified, distinguished by their maximum working pressure: a) Type R7: hoses with one or more layers of reinforcement; b) Type R8: hoses with one or more layers of reinforcement, for operation at higher working pressures; c) Type R18: hoses with one or more layers of reinforcement, 21,0 MPa (210 bar) working pressure based. Each type of hose is divided into two classes according to its electrical properties: — Class 1, no electrical requirements; — Class 2, “non-conductive” (see 7.8). 5 Materials and construction 5.1 Hoses Hoses shall consist of a seamless thermoplastic lining resistant to hydraulic fluids, with suitable textile yarn reinforcement and a thermoplastic cover resistant to hydraulic fluids, water and the weather. For class 2 hoses, the cover shall not be perforated. The cover shall be orange (colour code RAL 2004). 5.2 Hose assemblies Hose assemblies shall only be manufactured with those hose fittings whose functionality conforms to the requirements of 7.1, 7.4, 7.5 and, for class 2 only, 7.8. 6 Dimensions and tolerances 6.1 Diameters When measured in accordance with ISO 4671, the diameters of the hoses shall conform to the values given in Table 1.
7.6 Cold flexibility When tested in accordance with method B of ISO 10619-2:2017 at a temperature of −40 °C, there shall be no cracking of the lining or cover. The test piece shall not leak or crack when subjected to a proof pressure test in accordance with ISO 1402 after regaining ambient temperature. 7.7 Ozone resistance When tested in accordance with method 1 or 2 of ISO 7326:2016, depending on the nominal bore of the hose, no cracking or deterioration of the cover shall be visible under ×2 magnification. 7.8 Electrical conductivity This test applies to class 2 hoses only. When tested in accordance with Annex D, the current reading shall be no greater than 50 µA. 7.9 Fluid resistance 7.9.1 Test pieces The fluid resistance tests specified in 7.9.2 to 7.9.4 shall be carried out on moulded sheets of lining and cover material having a minimum thickness of 2 mm.