Section 02.03.03.670 - CHEMICAL INJECTION SYSTEMAll chemical injection systems, except for flood, basin, furrow, or border chemigation through a gravity flow system, will use either: (3-15-22)
01.Metering Pump. Such as a positive displacement injection pump effectively designed and constructed of materials that are compatible with chemicals and capable of being fitted with a system interlock; or (3-15-22)02.Venturi System. Including those inserted directly into the main water line, those installed in a bypass system, and those bypass systems boosted with an auxiliary water pump that meet the following criteria: (3-15-22)a. Booster or auxiliary water pumps shall be connected with the system interlock such that they are automatically shut off when the main line irrigation pump stops, or in cases where there is no main line irrigation pump, when the water pressure decreases to the point where pesticide distribution is adversely affected; (3-15-22)b. Venturies shall be constructed of chemically resistant materials; and (3-15-22)c. The line from the chemical supply tank to the Venturi will contain a functional, automatic, quick closing check valve to prevent the flow of liquid back toward the chemical supply tank. This valve will be located immediately adjacent to the Venturi chemical inlet. (3-15-22)d. This same supply line will also contain either a functional normally closed solenoid-operated valve connected to the system interlock or a functional normally closed hydraulically operated valve which opens only when the main water line is adequately pressurized. (3-15-22)e. In bypass systems as an option to placing both valves in the line from the chemical supply tank, the check valve may be installed in the bypass immediately upstream of the Venturi water inlet and either the normally closed solenoid or hydraulically operated valve may be installed immediately downstream of the Venturi water outlet. (3-15-22)Idaho Admin. Code r. 02.03.03.670