Overview
ISO 4679:2023 - Ships and marine technology - Hydraulic performance tests for waterjet propulsion system - defines measurement methods, acceptance criteria and test-report requirements for hydraulic performance testing of waterjet propulsion systems. It covers tests for waterjet pumps with and without inlet ducts, specifies two precision grades (Class A and Class B), and sets the conditions and equipment requirements needed to achieve the stated accuracy. The standard excludes ancillary parts of the waterjet unit such as steering/reversing gear, hydraulic systems and control systems.
Key topics and technical requirements
- Scope and precision grades
- Class A: precision grade for hydraulic model tests.
- Class B: precision grade for acceptance tests of small and mid-sized or intermediate test models.
- Measured and derived parameters
- Direct measurements: flow rate, pressure (inlet/outlet), torque, rotational speed.
- Derived values: pump total head, shaft power, pump efficiency.
- Acceptance criteria (percent of guarantee values) - Table values from the standard:
- Flow rate: Class A ±1.5%, Class B ±2.0%
- Speed of rotation: Class A ±0.2%, Class B ±0.5%
- Torque: Class A ±1.0%, Class B ±1.4%
- Pump total head: Class A ±1.0%, Class B ±1.5%
- Pump power input: Class A ±1.0%, Class B ±1.5%
- Pump efficiency: Class A ±2.25%, Class B ±2.9%
- Measurement range and operating windows
- Flow measured from 80% to 110% of the best-efficiency or duty point.
- Allowed speed variation: Class A ±20%; Class B range 60%–120% of specified speed.
- Measurement uncertainty
- Statistical evaluation of random and systematic uncertainties, overall uncertainty, and conversion/translation of results to guarantee conditions.
- Test methods and conditions
- Test location, personnel, dates, environment/water quality, test device requirements.
- Includes NPSH (Net Positive Suction Head) testing and recommendations for buffering high fluctuations in signals.
- Reporting
- Test report content and informative annexes provided (Annex A: test report example; Annex B: working section of test device).
Practical applications and users
ISO 4679 is used to:
- Validate waterjet pump performance during design, model testing and factory acceptance.
- Provide a contractually agreed method and acceptance criteria between manufacturers and purchasers.
- Support classification societies, marine test laboratories, naval architects, shipbuilders, and marine systems integrators in producing reproducible, traceable hydraulic test results.
Related standards
- ISO 9906 (rotodynamic pumps - test codes): referenced for head definitions.
- ISO 17769 (pump terminology and test concepts): referenced for power/efficiency definitions.
Keywords: ISO 4679, waterjet propulsion, hydraulic performance tests, waterjet pump, measurement uncertainty, acceptance criteria, Class A, Class B, NPSH, marine testing.