ATCP 29.54(7)(b) (b) A barometric loop may be installed in a chemigation system, in place of a reduced pressure principle backflow preventer under par. (a), if the chemigation system is not subject to back pressure. The barometric loop shall extend to an elevation at least 35 feet above the highest outlet in the chemigation system. The loop shall be installed in the water supply pipeline between the supply pump discharge and the point at which pesticides are injected.

ATCP 29.54(7)(c) (c) Two check valves may be installed in a chemigation system, in place of a reduced pressure principle backflow preventer under par. (a), if the chemigation system draws from surface waters. The check valves shall be connected in series, and shall be installed in the water supply pipeline between the supply pump discharge and the point at which pesticides are injected. Each check valve shall comply with par. (e), and shall be preceded by a vacuum relief valve under par. (g) and an automatic low pressure drain valve under par. (h).

ATCP 29.54(7)(d) (d) A check valve followed by a gooseneck loop may be installed in a chemigation system, in place of a reduced pressure principle backflow preventer under par. (a), if all of the following conditions are met:

ATCP 29.54(7)(d)1. 1. The chemigation system draws water from surface waters that are higher in elevation than the surface being chemigated.

ATCP 29.54(7)(d)2. 2. The check valve complies with par. (e), and is preceded by an automatic low pressure drain valve under par. (h).

ATCP 29.54(7)(d)3. 3. The gooseneck loop complies with par. (f).

ATCP 29.54(7)(e) (e) A check valve under par. (c) or (d) shall be all of the following:

ATCP 29.54(7)(e)1. 1. Quick-closing by spring action.

ATCP 29.54(7)(e)2. 2. Certified for compliance with underwriters’ laboratory (UL) standard 312.

ATCP 29.54 Note Note: UL Standard 312, published by the underwriters’ laboratory, is on file with the department and the legislative reference bureau.

ATCP 29.54(7)(f) (f) A gooseneck loop under par. (d) shall be constructed and installed so that all of the following conditions are met:

ATCP 29.54(7)(f)1. 1. The irrigation pump is located at a higher elevation than the water source.

ATCP 29.54(7)(f)2. 2. The bottom of the pipe at the apex of the gooseneck loop is at least 24 inches higher in elevation than the highest outlet in the chemigation system.

ATCP 29.54(7)(f)3. 3. The pesticide injection port is located downstream from the gooseneck loop at a point at least 6 inches lower in elevation than the bottom of the pipe at the apex of the loop.

ATCP 29.54(7)(f)4. 4. A vacuum relief valve under par. (g) is installed in the top of the pipe at the apex of the gooseneck loop.

ATCP 29.54(7)(g) (g) Each vacuum relief valve under par. (c) or (f) 4. shall be installed on top of the horizontal water supply pipeline on the supply side of the check valve. The diameter of the vacuum relief valve orifice shall be at least 3/4 inch if the water supply pipe has a nominal inside diameter of 4 inches or less; at least one inch if the pipe diameter is 5 to 8 inches; and at least 2 inches if the pipe diameter is 10 to 12 inches.

ATCP 29.54(7)(h) (h) Each automatic low pressure drain valve under par. (c) or (d) 2. shall be installed on the bottom of the horizontal water supply pipeline on the supply side of the check valve. The automatic low pressure drain valve shall have a minimum orifice diameter of 3/4 inch. The valve shall not extend upward beyond the inside surface of the bottom of the water supply pipeline. The drain outlet shall be located above grade at a distance of at least 2 inches or twice the diameter of the drain outlet, whichever is greater. The drain outlet shall be installed and located so that, when draining occurs, the drained liquid will flow away from any nearby wellhead or surface water.

ATCP 29.54(8) (8) Flow interrupter; pesticide supply line. In every chemigation system, a flow interrupter shall be installed in the pesticide supply line between the pesticide injection unit and the pesticide supply tank. The flow interrupter shall be designed to stop the flow through the pesticide supply line if the pesticide injection unit stops operating. The flow interrupter may consist of a normally closed, solenoid-operated valve or similar device which forms part of the interlock system under sub. (11).

ATCP 29.54(9) (9) Flow sensor; injection line. In every chemigation system, a flow sensor or pressure switch shall be installed at or near the outlet of the injection pump on the injection line. The flow sensor or pressure switch shall be installed so that, if the injection line fails for any reason, the flow sensor or pressure switch will shut off the injection pump.

ATCP 29.54(10) (10) Check valve; pesticide injection line. In every chemigation system, a check valve shall be installed in the pesticide injection line between the pesticide injection unit and the point at which pesticides are injected into the water supply. The check valve shall be spring loaded and have a minimum opening or cracking pressure of 10 pounds per square inch.

ATCP 29.54(11) (11) Interlock between water pump and pesticide injection unit. In every chemigation system, there shall be a mechanical or electrical interlock between the water supply pump and the pesticide injection unit. If the flow of water is interrupted, the interlock shall immediately shut off the pesticide injection unit.

ATCP 29.54(12) (12) Water pressure failure; automatic shut-off. In every chemigation system, a low pressure switch shall be effectively designed and installed to shut off power to the application system if water pressure decreases to the point that the pesticide application no longer complies with the pesticide label directions.

ATCP 29.54(13) (13) Purging a chemigation system. After pesticide injection is completed, water shall be pumped through a chemigation system for at least the flush time of the application system.

ATCP 29.54(14) (14) Chemigation operating plan; contents. A chemigation system shall be operated according to a written operating plan that describes all of the following:

ATCP 29.54(14)(a) (a) Sensitive nontarget areas that may be subject to overspray or drift from the chemigation system. Sensitive nontarget areas include all of the following:

ATCP 29.54(14)(a)1. 1. Surface water.

ATCP 29.54(14)(a)2. 2. Wetlands.

ATCP 29.54(14)(a)3. 3. Public roads within 100 feet of the application site.

ATCP 29.54(14)(a)4. 4. Residences, migrant labor camps, schools, playgrounds, day care facilities, health care facilities, commercial or industrial facilities, public recreation areas or other areas, located within 300 feet of the application site, at which individuals are likely to be present during the chemigation application.