Detail of GB/T 27612.3-2023

Introduction of GB/T 27612.3-2023

Agricultural irrigation equipment - Sprinklers - Part 3: Characterization of distribution and test methods 1 Scope This document specifies the conditions and methods used for testing and characterizing the water distribution patterns of irrigation sprinklers. The term sprinkler is used in this document in a broad generic sense and is meant to cover a wide variety of products. The specific performance measurements addressed include distribution uniformity, wetted radius, and water jet trajectory height. Three performance measurements are required to verify the design objectives as defined by the manufacturer. This document deals both with indoor and outdoor tests and with radial and full grid tests. It is organized so as to deal with conditions common to all tests first and then with conditions unique to indoor testing only and finally with conditions unique to outdoor testing only. For any given sprinkler, a wide range of nozzle configurations, operating conditions, and adjustments generate 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. This document does not address the specific performance testing required for sprinklers intended for use in frost protection. This document does not address the topic of drop spectrum measurement and characterization and the related questions of soil compaction, spray drift, evaporative losses, etc., all of which can be considerations in the design of sprinkler irrigation systems. This document is used for evaluating irrigation coverage of sprinklers that are identical and arranged in a fixed repeating geometric pattern. This document does not apply to moving systems. This document applies to part-circle sprinklers provided that the testing agency can satisfy questions of potential anomalies in performance parameters. Note: Annex A addresses the procedures for the characterization of sprinkler pattern uniformity. Annex B addresses testing part-circle sprinklers. 2 Normative references There are no normative references in this document. 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 the sprinkler operated within the range of effective application rates (3.9) specified in the manufacturer's literature 3.3 Christiansen's uniformity coefficient UCC coefficient using deviations from the mean to characterize the uniformity of field-measured or simulated water application from a grid of sprinklers 3.4 clean water water processed, if necessary, so as to contain suspended particles no larger than 74 μm (200-mesh equivalent) and to contain no dissolved chemicals known to have short-term effects on sprinklers materials 3.5 collector receptacle into which water is deposited during a water distribution test 3.6 critical dry area experience-based definition of the dry area size that defines uniformity of coverage objectives 3.7 densogram areal map utilizing the density of dots representing water application depth at locations in the area of coverage (3.2) of a sprinkler or a grid of sprinklers 3.8 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 3.9 effective application rate application rate equal to or exceeding 0.26 mm/h for sprinklers with flow rates (3.11) exceeding 120L/h and 0.13 mm/h for sprinklers with flow rates equal to or less than 120L/h 3.10 effective radius of throw radius at which 95 % of the reconstituted volume of water discharged by a sprinkler, interpolated between points of measurement, is applied 3.11 flow rate volume of water flowing through a device per unit time 3.12 full grid collector array collectors (3.5) 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 (3.8) 3.13 inlet connection size numerical designation used to characterize the sprinkler which is identical to the size of the connection to the irrigation pipe 3.14 irrigation lateral branch supply line in an irrigation system on which distribution devices are mounted directly or by means of fittings, risers, or tubes 3.15 nozzle aperture of a sprinkler through which water is discharged 3.16 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 3.17 pop-up sprinkler sprinkler designed for installation so that the sprinkler nozzle automatically raises from below ground when the system is pressurized and automatically lowers to its original position when the system is depressurized 3.18 pressure tap precisely fabricated connection for communicating internal conduit pressure to an external pressure-measuring device 3.19 radial collector arrays method collectors (3.5) located only on a radial axis projected from the centreline of a sprinkler sufficient in number to characterize the water distribution curve 3.20 radius of throw wetted radius 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 (3.9), measured at any arc of coverage except near the arc extremes for part-circle sprinklers 3.21 range of working pressure pressures between the minimum working pressure and the maximum working pressure 3.22 rotating sprinkler 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 3.23 scheduling coefficient SC coefficient used to characterize the water application uniformity of sprinklers employing an analysis of full-grid test databased on a definition of critical dry area (3.6) 3.24 sprinkler spacing conventional designation including the distance between the sprinklers along an irrigation lateral (3.14) and the distance between consecutive irrigation laterals 3.25 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 3.26 test pressure pressure at the inlet of a sprinkler declared by the manufacturer as the pressure to be used for test purposes 3.27 maximum trajectory height maximum height above a sprinkler of the trajectory of the water stream discharged from the sprinkler nozzle operating under the test pressure (3.26)

Contents of GB/T 27612.3-2023