WAC 16-230-170   Desiccants and defoliants -- Aerial equipment -- Boom length, pressure, nozzle requirement, nozzle height of discharge and smoke device requirements for the entire area under order.  The following requirements apply to the entire area under order as listed in WAC 16-230-150:

     (1) Boom length restrictions:

     (a) Fixed wing: The working boom length shall not exceed 3/4 of the distance from the center of aircraft to wing tip on each side of aircraft.

     (b) Helicopters: The working boom length shall not exceed 6/7 of the distance from the center of rotor to rotor tip on each side of the aircraft for rotors 40 feet or under or 3/4 of the distance from the center of rotor to rotor tip on each side of the aircraft where the rotor exceeds 40 feet while applying use restricted desiccants and defoliants.

     (2) Pressure restrictions: Maximum pressure at the nozzles for all aerial applications of use restricted desiccants and defoliants shall be 25 psi.

     (3) Nozzle requirements for applications of use restricted desiccants and defoliants:

     (a) Fixed wing:

     (i) Aircraft shall not be equipped with core plates or any device or mechanism which would cause a sheet, cone, fan or other dispersion of the discharged material. Nozzle orifices shall not be less than 0.094 inches: Provided, That the RD8-46 Raindrop¦ nozzles may be used with a minimum orifice diameter of 0.156 inches;

     (ii) Nozzles shall be directed downward and backward 135 degrees from the direction of flight.

     (b) Helicopter:

     (i) Straight stream jet nozzles, without core plates, with a minimum orifice diameter of 0.063 inches;

     (ii) Straight stream jet nozzles with a minimum orifice diameter of 0.125 inches with No. 46 core plates or larger;

     (iii) RD8-46 Raindrop¦ nozzles may be used with a minimum orifice diameter of .075 inches;

     (iv) Nozzles shall be directed downward and backward 135 degrees from the direction of flight for applications over 50 miles per hour and 90 degrees downward and backward for applications under 50 miles per hour.

     (4) Height of discharge requirements by aircraft of use restricted desiccants and defoliants: The nozzles must be closed while either descending onto or ascending from the target field, and also ascending or descending over an obstacle or obstruction within the target field that would alter the height of application more than ten feet.

     (5) Smoke device requirements: All aircraft applying use restricted desiccants and defoliants shall utilize a smoke device to determine wind directions and temperature inversion situations.

     (6) The Washington state department of agriculture may issue a permit upon receipt of a written request to apply use restricted desiccants and defoliants within the area under order as described in WAC 16-230-150 with nozzles, nozzle type, drift control additives and/or arrangements other than those allowed herein. The director will consider safety factors and the possible exposure to susceptible crops in the areas of proposed application before a permit will be issued.

     (7) Diesel and other fuel oils are prohibited in all tank mixes with desiccants and defoliants.

     (8) Aerial applications of desiccants and defoliants are prohibited within a distance of one mile of the city limits of any incorporated city or town and the same distance from the center of any unincorporated city or town comprised of ten or more inhabited, closely grouped residences.



[Statutory Authority: Chapters 17.21, 15.58, and 34.05 RCW. 07-11-041A, § 16-230-170, filed 5/9/07, effective 6/9/07. Statutory Authority: Chapters 15.58 and 17.21 RCW. 91-08-058 (Order 2081), § 16-230-170, filed 4/2/91, effective 5/3/91. Statutory Authority: RCW 17.21.030. 82-14-081 (Order 1767), § 16-230-170, filed 7/6/82. Statutory Authority: Chapters 15.58 and 17.21 RCW. 80-05-005 (Order 1682), § 16-230-170, filed 4/4/80; 79-02-046 (Order 1591), § 16-230-170, filed 1/29/79; 78-02-053 (Order 1548), § 16-230-170, filed 1/19/78; Order 1545, § 16-230-170, filed 11/30/77.]