Overview
EN ISO 1179-4:2008 (ISO 1179-4:2007) specifies dimensions, performance requirements and test procedures for stud ends with ISO 228-1 threads and metal-to-metal sealing (type B) for general use. The standard applies to stud ends used with ports and connectors in piping and couplings but explicitly states these stud ends are not intended for leak-free hydraulic fluid power applications. It was adopted by CEN (European Standard) and is commonly referenced by manufacturers and test laboratories for legacy and general-purpose connector designs.
Key topics and technical requirements
- Threading and dimensions: Stud ends conform to ISO 228-1 thread form and the dimensional tables and figures given in EN ISO 1179-4. Hex tolerances are per ISO 4759-1 (product grade C).
- Series and working pressure: Stud ends are grouped in series (LL, L, S) with representative working pressures:
- LL series: up to 10 MPa (100 bar)
- L series: up to 25 MPa (250 bar)
- S series: up to 40 MPa (400 bar)
(Permissible pressure depends on size, material and application.)
- Performance testing:
- Burst (failure) test: three samples to demonstrate a minimum burst-to-working pressure ratio of 4:1.
- Cyclic endurance (impulse) test: six samples to pass 1,000,000 cycles at the specified impulse pressure.
- Test blocks, procedures and pressure rise rates reference ISO 19879.
- Threads and contact surfaces are lubricated for testing as specified in ISO 19879.
- Materials and reuse: Tests are based on low carbon steel plated stud ends. Metal-to-metal sealing uses a machined sealing edge that is compressed during assembly - this damages the port sealing face so re‑use or safe reassembly is not possible.
- Designation and identification: Standardized designation (e.g., “Stud end ISO 1179-4 - G 3/8 A-S”) and mandatory identification statements for catalogs and test reports.
Applications and who uses this standard
- Manufacturers of pipe fittings, stud ends and connectors for general industrial fluid conveyance.
- Design engineers specifying threaded connectors for non-leak‑critical hydraulic or pneumatic systems.
- Test laboratories and quality control teams performing burst and impulse testing.
- Technical writers and procurement teams referencing compatibility with ISO 8434 connector series.
Note: For new hydraulic fluid‑power designs requiring leak-free performance, ISO 6149 (metric O‑ring ports) is the recommended alternative.
Related standards
Keywords: EN ISO 1179-4:2008, ISO 1179-4, stud ends, ISO 228-1 threads, metal-to-metal sealing, fluid power, working pressure, burst test, impulse test, connectors.
