Overview
EN ISO 11545:2009 (adopted by CEN as EN ISO 11545:2009) defines an in-field method to determine the uniformity of water distribution from centre‑pivot and moving‑lateral irrigation machines fitted with sprayer or sprinkler nozzles. The standard specifies how to measure applied depth using collectors, how to calculate the coefficient of uniformity, and how to record and report test results. It applies to irrigation machines with water‑application devices more than 1.5 m above the soil surface and where distributions from successive devices overlap. It does not apply to centre‑pivot systems using special corner‑arm application devices.
Key topics and technical requirements
- Test scope and applicability: centre‑pivot and moving‑lateral machines with overlapping sprinkler patterns; excludes corner‑arm evaluations.
- Collectors: identical receptacles required; entrance height and geometry limits; minimum dimensions (e.g., height ≥ 150 mm, opening diameter ≥ 85 mm, opening diameter ≥ half the collector height) to reduce measurement error.
- Collector layout: collectors placed along two or more straight lines (radial for pivots, parallel for laterals) with specified spacing relative to sprinkler wetted radius; offset lines recommended to minimize systematic errors.
- Environmental controls: wind measured with anemometer at 2 m height; test accuracy decreases above 1 m/s and is not valid above 5 m/s unless client and tester agree; evaporation and elevation are accounted for in test conditions.
- Test procedures and calculations: step‑by‑step field test methods, calculation of applied depth and the coefficient of uniformity, evaluation criteria and permissible test conditions.
- Reporting: standard includes required data sheets and sample test report forms (Annex A) to ensure consistent documentation.
Practical applications
- Verify and compare water distribution uniformity of centre‑pivot and moving‑lateral irrigation machines.
- Support irrigation system commissioning, performance certification, and routine diagnostics.
- Provide objective data for irrigation designers, manufacturers, test laboratories, agronomists and large‑scale farmers to optimize nozzle selection, spacing, and operating pressure.
- Inform water‑use efficiency improvements, irrigation scheduling and compliance with procurement or regulatory requirements.
Who should use this standard
- Irrigation equipment manufacturers and R&D teams
- Field testers and accredited test laboratories
- Agricultural consultants, irrigation designers and system installers
- Farm managers, agronomists and water resource planners
- Standards bodies and regulatory agencies overseeing irrigation performance
Related standards
- ISO 11545:2009 supersedes the previous edition (ISO 11545:2001) and was prepared by ISO/TC 23 (Tractors and machinery for agriculture and forestry) in collaboration with CEN/TC 334. For comprehensive testing programs, consult adjacent ISO/CEN irrigation standards and national adoption documents.
Keywords: EN ISO 11545:2009, water distribution uniformity, coefficient of uniformity, centre‑pivot irrigation, moving lateral, sprinkler nozzles, irrigation testing, collectors, anemometer, irrigation equipment performance.
