What does the '20% rule' refer to when selecting a pump for pesticide applications?

• A. Capacity allowance for agitation, desired nozzle output, and loss of pump capacity
• B. Maximum nozzle output per minute
• C. Minimum pump horsepower required
• D. Recommended backflow distance

Answer: (A)

In selecting a pump for pesticide applications, you size it with about 20% extra capacity to cover real-world losses. That headroom accounts for agitation (the mixer consuming some flow), the actual nozzle output under operating pressure (it’s often lower than the rating), and losses within the pump itself. This ensures the system can still deliver the desired spray rate even when conditions aren’t perfect. The choice describing an allowance for agitation, the desired nozzle output, and loss of pump capacity matches this idea. The other options don’t fit because they focus on maximum nozzle output, minimum horsepower, or backflow distance, none of which describe adding headroom for these losses. For example, if you need 10 gpm, aim for a pump that can deliver about 12 gpm at the operating pressure.