Use the salt spreader calibration worksheet to record what a catch test delivered, then explicitly choose measured or target basis for named manual areas.
1. Measure net weight and spread width
Follow the spreader's collection method. Weigh net discharged material after removing container tare. Measure where material spreads or bounces, not intended pass spacing. MPCA's Smart Salting for Parking Lots & Sidewalks (August 2022), pages 51-52 and Table 8, supply the measured-catch example.
2. Measured-distance example
MPCA records 20 mph, a half-closed setting, a 0.4 lb catch, 13 ft spread width and 10 ft test distance. Area is 13 x 10 = 130 ft2. Rate is 0.4 x 1000 / 130 = 3.076923... lb/1000 ft2. The source displays 3.1; the calculator retains unrounded arithmetic. A partial-width pan catch is not total discharge.
3. Timed verification example
Mn/DOT Snowplow Salt and Sander Controller Calibration Guide (December 21, 2009), printed page 65 / PDF page 70, expects 250 lb for a 500 lb/mile setting at 30 mph for 60 seconds. Catching 260 lb is +4%. A 12 ft-wide adaptation gives distance 2640 ft, area 31680 ft2, target catch 250 lb and measured rate 8.207070... lb/1000 ft2.
4. Keep the measured setting with the result
Record material, named setting, equipment, operator, local date, test method and speed with its original unit. Repeat the measurement after an adjustment. A target-basis plan does not demonstrate that the current setting delivers that target. The worksheet gives no automatic dial correction.
5. Pool bags and separate costs
A measured-basis 63360 ft2 route in the timed example requires 520 lb. With 50 lb bags and 250 lb usable loose capacity, that is 11 bags and 3 loose-material loads. Purchased mass is 550 lb; unused stock is 30 lb. At 10 per bag, applied material cost is 104 and whole-bag purchase cost is 110. Loose loads use required mass, not intact purchased bags. These are derived material costs, not an application quote.
6. Print and re-test
Print the calibration card and route sheet with basis, both-unit rate, labels and date. Follow equipment and product procedures. No treatment, uniformity, pavement-safety, axle or legal-payload verdict is produced. Numeric precision does not establish measurement accuracy.