Overview
ISO 6802:2018 - "Rubber or plastics hoses and hose assemblies - Hydraulic impulse test with flexing" specifies a standardized method for impulse testing hydraulic rubber or plastic hose assemblies while subjecting them to flexing motion. The procedure covers both high-pressure (> 3 MPa) and low-pressure (1.5 MPa to 3 MPa) impulse regimes and is intended for hose assemblies that experience pulsating pressures and movement in service. An optional cool-down leakage test is included (Annex A). Note: impulse tests without flexing are covered by ISO 6803.
Key topics and technical requirements
- Test scope: Applies to complete hose assemblies with fittings; typically four unaged samples unless otherwise specified.
- Pressure ranges: High-pressure > 3 MPa; low-pressure 1.5–3 MPa.
- Flexing methods: Two apparatus layouts - a revolving manifold (Method 1) or a horizontally sliding manifold (Method 2). The movable manifold remains parallel to the stationary manifold.
- Flex geometry:
- Distance from stationary centreline: l = 1.75·r + d_ext (±2 mm)
- Free hose length between couplings: L = 4.14·r + 3.57·d_ext (±15 mm)
- r = minimum bend radius; d_ext = external hose diameter
- Cycle relationship: Movable manifold cycles per minute = 34–38% of impulse cycles per minute (flex cycles proportional to impulse cycles).
- Test fluid: Recommend kinematic viscosity ISO VG 32–100 (32–100 mm²/s at 40 °C, per ISO 3448). Other fluids may be agreed between manufacturer and customer.
- Failure and leakage: Leakage less than Class 4 (ISO/TR 11340) is not a failure. Failures near fittings (within 25 mm) are recorded as fitting failures.
- Optional cool-down leakage test: Cool to ~30 °C (±10 °C) at 40% ±10% and 90% ±10% of cycles, then resume and observe leakage for 1 000 cycles.
- Reporting: Test report must record test method, temperature, pressure, fluid, impulse rate, flex frequency, cycles to failure or completion, failure mode/position, fittings details, and whether cool-down test was used.
Applications and users
- Hydraulic hose and hose assembly manufacturers - design verification and product qualification.
- Test laboratories and third‑party certification bodies - compliance testing and quality assurance.
- OEMs and system integrators - selection and validation of hoses used in mobile and industrial hydraulic systems subject to pulsation and movement.
- Maintenance and reliability engineers - failure analysis, lifecycle expectations, and procurement specifications.
Related standards
- ISO 6803 - Hydraulic-pressure impulse test without flexing
- ISO/TR 11340 - External leakage classification for hydraulic systems
- ISO 3448 - Viscosity classification for test fluids
- ISO 8330 - Hoses and hose assemblies vocabulary
Keywords: ISO 6802:2018, hydraulic impulse test with flexing, rubber hoses, plastics hoses, hose assemblies, flex test rig, cool down leakage test, ISO VG 32-100.
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