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 Washington Administrative Code (Last Updated: November 23, 2016)
 Title 16. Agriculture, Department of (See Titles 24, 60, and 142)
 Chapter 16-230. Use of chemicals and chemically treated materials in certain counties.

  Section 16-230-675. Use restricted herbicides—Eastern Washington—Minimum nozzle orifice and core plate sizes for aircraft application.  

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  • Minimum nozzle orifice and core plate sizes shall be as listed in the dormant season, caution, warning, and danger area restrictions.
    (1) DORMANT SEASON AREA. (Dormant season only - Refer to specific county regulations.)
    (a) Fixed wing -
    (i) Minimum nozzle orifice of 0.063 inches (no core plate). Nozzles shall be directed downward and backward 135 degrees or more from the direction of flight.
    (ii) Minimum nozzle orifice of 0.075 inches (may use No. 45 or larger core plate) and nozzles shall be directed downward and backward 170 degrees or more from the direction of flight.
    (b) Helicopter -
    Minimum nozzle orifice of 0.047 inches (may use No. 45 or larger core plate) and nozzles shall be directed downward and backward 90 degrees or more from the direction of flight. Pressure over 35 psi is prohibited.
    (2) CAUTION AREA.
    (a) Fixed wing -
    (i) Minimum nozzle orifice of 0.075 inches (no core plate). Nozzles shall be directed downward and backward 135 degrees or more from the direction of flight.
    (ii) Minimum nozzle orifice of 0.125 inches (may use No. 45 or larger core plate). Nozzles shall be directed downward and backward 170 degrees or more from the direction of flight.
    (b) Helicopter -
    (i) Area 2 of all counties restricted by rule -
    Minimum nozzle orifice of 0.063 inches (may use No. 46 or larger core plate). Nozzles shall be directed downward and backward 90 degrees or more from the direction of flight.
    (ii) Areas 3 and 4 of all counties restricted by rule -
    Minimum nozzle orifice of 0.063 inches (may use No. 45 or larger core plate). Nozzles shall be directed downward and backward 90 degrees or more from the direction of flight.
    (3) WARNING AREA
    (a) Fixed wing -
    (i) Minimum nozzle orifice of 0.075 inches (no core plate). Nozzles shall be directed downward and backward 135 degrees or more from the direction of flight.
    (ii) Minimum nozzle orifice of 0.125 inches (may use No. 46 or larger core plate in all counties under order except Franklin County and Benton County). Nozzles shall be directed downward and backward 170 degrees or more from the direction of flight: Provided, That RD8 nozzles with orifice size of 0.125 inches and No. 45 core plates may be used. Nozzles shall be directed downward and backward 170 degrees or more from direction of flight.
    (iii) No flat fan nozzles shall be allowed.
    (b) Helicopter -
    (i) Minimum nozzle orifice of 0.047 inches for applications made under sixty miles per hour (no core plate) and minimum orifice of 0.063 for applications made over sixty miles per hour (no core plate). Nozzles shall be directed downward and backward 90 degrees or more from the direction of flight.
    (ii) Minimum nozzle orifice of 0.125 inches (may use No. 46 or larger core plate in all counties under order except Franklin County and Benton County). Nozzles shall be directed downward and backward 90 degrees or more from the direction of flight: Provided, That RD8 nozzles with orifice size of 0.125 inches and No. 45 core plates may be used.
    (iii) No flat fan nozzles shall be allowed.
    (4) DANGER AREA
    (a) Fixed wing - Minimum nozzle or
    (i) Minimum nozzle orifice of 0.075 inches (no core plate): Provided, That RD8 nozzles with orifice size of 0.125 inches and No. 46 core plates may be used. Nozzles shall be directed downward and backward 170 degrees or more from the direction of flight.
    (ii) No flat fan nozzles shall be allowed.
    (b) Helicopter -
    (i) Minimum nozzle orifice of 0.063 inches (no core plate): Provided, That RD8 nozzles with orifice size of 0.125 inches and core plate No. 46 may be used. Nozzles shall be directed downward and backward 90 degrees or more from the direction of flight.
    (ii) No flat fan nozzles shall be allowed.
    [Statutory Authority: Chapters 17.21, 15.58, and 34.05 RCW. WSR 07-11-041A, § 16-230-675, filed 5/9/07, effective 6/9/07. Statutory Authority: Chapters 15.58 and 17.21 RCW. WSR 91-06-019 (Order 2073), § 16-230-675, filed 2/26/91, effective 3/29/91; WSR 80-03-041 (Order 1680), § 16-230-675, filed 2/20/80.]
Chapters 17.21, 15.58, and 34.05 RCW. WSR 07-11-041A, § 16-230-675, filed 5/9/07, effective 6/9/07. Statutory Authority: Chapters 15.58 and 17.21 RCW. WSR 91-06-019 (Order 2073), § 16-230-675, filed 2/26/91, effective 3/29/91; WSR 80-03-041 (Order 1680), § 16-230-675, filed 2/20/80.