2.1 Powered Outdoor Applications, Weather & Drift Control (CMR 01-026 Ch. 22)
Key Takeaways
- Chapter 22 applies to outdoor pesticide applications made with powered equipment and requires planning and operation that minimize off-target deposition.
- Covered sensitive areas within 500 feet must be identified and recorded under the rule's category-specific provisions.
- Powered applications are prohibited above 15 mph; aerial applications within 1,000 feet of a sensitive area likely to be occupied require wind from 2 through 10 mph.
- Powered equipment must be calibrated and maintained with usable shutoffs and antisiphon protection, and required calibration information must be retained.
- Chapter 22 does not create a universal water or sensitive-area buffer; labels, Chapter 29, and other site rules can impose separate setbacks.
Powered Outdoor Applications and Drift Control
CMR 01-026 Chapter 22 governs outdoor pesticide applications made with powered equipment. Its purpose is to minimize off-target deposition through planning, equipment condition, calibration, weather limits, and operator control. It does not replace the product label or create one universal water buffer.
Scope and planning
Powered equipment includes motorized ground equipment and aircraft used to deliver pesticides outdoors. Before treatment, identify the target, boundaries, nearby sensitive areas, application method, and weather conditions. Chapter 22 requires covered sensitive areas within 500 feet to be identified and recorded, with provisions and exceptions tied to particular application categories.
A sensitive area analysis should include places where people may be present, water and wetlands, crops or property susceptible to injury, and other locations covered by the rule. Measure from the application site using the rule's definitions; do not substitute a guess based on property ownership. Record the result so the application plan can be reconstructed.
Chapter 22's 500-foot planning distance is not the Chapter 28 Notification Registry boundary and not the Chapter 29 untreated water buffer. Several rules may apply to one site.
Wind limits
A powered outdoor application is prohibited when wind velocity exceeds 15 miles per hour at the application site. If the label sets a lower maximum, follow the label. Measure representative conditions where and when treatment occurs and stop when the controlling limit is exceeded.
A special rule applies to aerial application within 1,000 feet of a sensitive area likely to be occupied: wind must be at least 2 and no more than 10 miles per hour. This narrower range should not be generalized to every ground application.
Low wind does not automatically mean low risk. Temperature inversions can suspend small droplets and move them later when air begins to flow. Chapter 22's numerical rule should be distinguished from sound drift-management judgment and label restrictions. Watch for inversion indicators, changing wind direction, gusts, high temperature, and low humidity, and delay when the pesticide cannot remain on target.
| Situation | Controlling Chapter 22 point |
|---|---|
| Any covered powered outdoor application | Do not apply above 15 mph, or above a lower label maximum |
| Aerial application within 1,000 feet of a sensitive area likely to be occupied | Apply only with wind from 2 through 10 mph and satisfy all other conditions |
| Sensitive area within 500 feet | Identify and record it as Chapter 22 requires, subject to the rule's category provisions |
| Nearby water | Check Chapter 29 and the label; do not invent a Chapter 22 water buffer |
| Registry participant or notice request | Apply Chapter 28 separately |
Equipment condition and control
The applicator must be able to start and stop delivery promptly. Functional shutoff controls prevent release while turning, crossing a boundary, or responding to a person entering the area. Hoses, pumps, valves, strainers, fittings, tanks, and nozzles must be maintained so they do not leak or deliver an erratic pattern.
Antisiphon or backflow protection keeps pesticide mixture from entering a water supply during filling. Maintain an air gap or approved device appropriate to the system. Never place a fill hose below the liquid surface without effective protection.
Nozzle selection, pressure, boom height, travel speed, and droplet size determine drift. Chapter 22 establishes a performance and equipment-control framework; the product label and nozzle manufacturer's table supply job-specific requirements. Use a nozzle and pressure that deliver the label-authorized rate and droplet class. Raising pressure generally makes droplets smaller for a given nozzle, increasing drift potential. Raising the boom increases the time droplets are exposed to wind. These are application principles, not excuses to depart from a label.
Calibration and records
Calibrate powered equipment before use and often enough to keep output within the intended rate. Retain the calibration information required by Chapter 22. A useful calibration record identifies the equipment, date, person, nozzle or metering setup, pressure, travel speed, measured output, swath or spacing, calculation, and corrective action.
For a ground boom, a common calibration equation is:
Use band width instead of nozzle spacing when the standard calculation calls for it. This equation estimates delivery volume; it does not determine the legal product rate. After finding gallons per acre, use the label rate and actual treatment area to determine product and carrier amounts.
Check individual nozzle output against the manufacturer's specifications and the boom average. Replace or correct a nozzle when output or pattern is outside the equipment or business tolerance. Chapter 22 does not create a universal “5 percent” replacement figure for every nozzle; use the manufacturer, calibration manual, label, and documented procedure.
On-site operating decisions
During the job:
- verify wind speed and direction before beginning and periodically afterward;
- watch the entire downwind area, not just the target immediately in front of the boom;
- keep boom or discharge height as low as the nozzle pattern and label permit;
- shut off flow before turning or crossing a boundary;
- stop for people, vehicles, unexpected sensitive activity, leaks, or weather change;
- prevent spray, granules, or dust from entering non-target property; and
- record the actual weather in the Chapter 50 application record when required.
Buffers can be required by the label or another Maine rule and can also be a prudent mitigation measure. Chapter 22 does not establish a universal buffer of a chosen width for all sensitive areas. The applicator must select conditions and equipment that keep the pesticide on target and must comply with every specific setback.
Scenario method
If a question gives 17 mph wind, the covered powered application must stop even if the operator uses coarse droplets. If an aerial application is 800 feet from an occupied sensitive area, apply the special 2-to-10-mph range. If a stream borders the site, look to Chapter 29 and the label for buffers in addition to Chapter 22. If a listed residence is nearby, analyze Chapter 28 notification separately.
The exam-ready sequence is: identify and record sensitive areas, inspect and calibrate equipment, verify the label and other Maine rules, measure site weather, apply only within the correct wind range, operate shutoffs and backflow protection, and stop whenever the pesticide cannot remain on target.
What is Chapter 22's maximum wind condition for a covered powered outdoor application when the label is not more restrictive?
An aerial application will occur 800 feet from a sensitive area likely to be occupied. What Chapter 22 wind range applies?
What should an applicator do with covered sensitive areas within 500 feet of the application site?
Which equipment feature helps prevent pesticide mixture from flowing backward into a water supply during filling?