GB/T 21402-2008

This standard specifies the component requirements and installation methods for water head controllers in pressure irrigation systems (referred to as irrigation water head controllers, with a standard size not exceeding 200 mm). This standard only applies to the above-ground components of water head controllers in sprinkler irrigation and micro-irrigation (such as small-scale sprinkler irrigation and drip irrigation) systems. It can also be applied to general irrigation water head controllers. On general irrigation water head controllers, other irrigation control and command elements (such as electrical, electronic, and hydraulic) can be installed, but they cannot be used for additional elements. This standard does not apply to irrigation water head controllers in systems and/or components with anti-freezing requirements, such as dry cylinder faucets or other forms of faucets. This standard does not provide specific design and operation requirements for the individual components that make up irrigation water head controllers. Detailed instructions are provided in their respective relevant standards. For irrigation water head controllers that include spray pesticide component systems, anti-backflow elements, spray detection valves, and other safety devices should be provided (in accordance with local standards and regulatory requirements), but such equipment requirements are not included in this standard.