Detail of GB/T 27612.4-2023

Introduction of GB/T 27612.4-2023

GB/T 27612.4-2023 Agricultural irrigation equipment - Sprinklers - Part 4: Test methods for durability 1 Scope This document specifies the conditions and methods for testing the durability of rotating sprinklers for irrigation. The term sprinkler is used here in a broad generic sense and is meant to cover a wide variety of products as classified in ISO 15886-1, which applies to all irrigation sprinkler classifications having both static parts and moving parts during operation, as defined by the manufacturer. For any given sprinkler, a wide range of nozzle configurations, operating conditions, and adjustments generates at least a theoretical need for a correspondingly large number of tests. Testing agencies and manufacturers can use interpolation techniques to reduce the number of actual test runs, provided accuracy standards are still being met. 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 15886-3:2012, Agricultural irrigation equipment - Sprinklers - Part 3: Characterization of distribution and test methods 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 ambient temperature temperature of the air surrounding a sprinkler 3.2 area of coverage area within the wetted boundary from a sprinkler operated within the range of effective application rates specified in the manufacturer’s literature 3.3 clean water water processed, if necessary, so as to contain suspended particles no larger than 74 microns (200 mesh) equivalent and to contain no dissolved chemicals known to have short‑term effects on sprinklers materials 3.4 distribution curve graphical plot of water application depth as a function of distance from a sprinkler along a specified radius 3.5 distribution uniformity DU coefficient using the lowest 25 % of water application depths to characterize the uniformity of field-measured or simulated water application from a grid of sprinklers 3.6 flow rate volume of water passing through a device per unit of time 3.7 full grid collector arrays collectors located at the intersections of a two-dimensional geometric grid pattern sufficient in number to give a desired statistical basis for determining water distribution uniformity (3.5) 3.8 inlet connection size nominal pipe size designation for commercial purposes or for manufacturer’s declaration defined by reference to a recognized standard 3.9 maximum working pressure Pmax highest water pressure at the inlet to a sprinkler recommended by the manufacturer to ensure proper operation 3.10 minimum working pressure Pmin lowest pressure at the inlet to a sprinkler recommended by the manufacturer to ensure proper operation 3.11 nozzle aperture of a sprinkler through which the water is discharged 3.12 nozzle pressure pressure measured immediately upstream from a nozzle (3.11) or as inferred by a Pitot tube measurement at the nozzle orifice 3.13 nozzle size numerical size designation used for commercial purposes with no specific relationship to the actual dimensions of a nozzle 3.14 part-circle sprinkler sprinkler with an adjustable feature that enables it to irrigate a sector of a circular area, either with or without an attachment which enables it to be adjusted to irrigate another sector or the entire circular area 3.15 regulated sprinkler sprinkler that maintains a relatively constant flow rate at varying water pressures at the sprinkler inlet within the limits specified by the manufacturer 3.16 radius of throw distance measured from a centreline of a continuously operating sprinkler to the most remote point at which the sprinkler deposits water at the minimum effective application rate, measured at any arc of coverage except near the arc extremes for part-circle sprinklers (3.14), also called wetted radius 3.17 rotating sprinkler water distribution device which, as a result of rotating motion around its axis, distributes water over a circular area, part of a circular area or a non‑circular area 3.18 statistical uniformity coefficient UCS coefficient using standard deviation as a measure of dispersion in statistical theory to characterize the uniformity of field-measured water application from a full grid of sprinklers 3.19 test pressure pressure at the inlet of a sprinkler declared by the manufacturer as the pressure to be used for test purposes 3.20 working pressure water pressure recommended by the manufacturer to ensure proper operation of a sprinkler 4 Installation of sprinklers under test The sprinkler selected for testing shall be representative of general production capabilities particularly as it relates to speed of rotation. Mount the test sprinkler in accordance with the manufacturer's installation instructions for normal operation in the field including the manner of installation, tightening torque, maximum/minimum force required to assemble. Mount the sprinkler on a riser with nominal size designation the same as the sprinkler inlet connection. Ensure that the riser is fixed rigidly vertically and that it does not vibrate enough to cause a visual effect on the sprinkler operation, bend or deviate from the vertical position during the test. The maximum allowable deviation from the vertical position during the test is 2°. The use of a steel pipe or a rigid plastic riser is recommended to provide the required mechanical strength and facilitate the installation of a standard pressure tap. If the manufacturer specifies any special operating conditions on items that are provided as standard equipment with the sprinkler, they shall be used. For a sprinkler which is not riser-mounted as described above, the test mounting shall be as specified by the manufacturer.

Contents of GB/T 27612.4-2023