WAC 16-230-655
WAC 16-230-655. Use restricted herbicides — Eastern Washington — Ground equipment application requirements
Ground applications of use restricted herbicides shall conform to the manufacturer's specified combination of nozzle type/size and pressure in pounds per square inch (psi) at the nozzle that produces a spray droplet size that falls within the medium (or larger) range as defined by the ASABE standards: Provided, That a pressure of 50 psi at the nozzle is the maximum that can be used for handgun applications when no manufacturer specified combination of nozzle and pressure for droplet size are available for that equipment. Upon request by the department the applicator shall provide all data which supports the nozzle configuration is compliant with the spray droplet classifications of medium or larger.