Split the route into treated areas and travel sections
Tank sizing begins with the area that actually receives water. Use route length and effective covered width, accounting for overlap or edges that do not receive the required treatment. Travel-only sections use time without adding treated area.
Apply a measured or approved rate for the surface and conditions. Dust, weather, speed and nozzle pattern can change that rate, so borrowing a number from another road can give a misleading result. A larger tank may reduce refills, but also changes mass, axle loading and the effects of moving liquid.
Check the water requirement against the complete refill cycle
Put travel, spraying, refill time and reserve on one timeline. If demand exceeds the truck’s usable and legally carried water, revise the refill plan or fleet requirement. The physical shell volume cannot override chassis and axle limits.
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| Decision | What to establish | Condition or limit |
|---|---|---|
| Treatment area | Calculate route length multiplied by effective covered width. | Nominal spray width may include overlap or unusable edge coverage. |
| Water demand | Use a documented application rate for the defined condition. | Do not borrow a rate from a different road, climate or nozzle setup. |
| Cycle design | Include travel, spraying, refill and reserve in one timeline. | Tank volume alone does not determine daily productivity. |
| Vehicle limits | Check usable water mass, completed mass and every axle reaction. | Geometric tank capacity cannot override legal or chassis limits. |
Estimate water demand from road area and application rate
A route estimate connects road area and an assumed application rate before reserve, refill access and payload are checked.
The hypothetical route needs 14,400 L before reserve. The result may support one larger load or a smaller tank with a documented refill cycle, subject to axle and operating limits.
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| Step | Calculation or condition | Result |
|---|---|---|
| Covered area | 4,000 m × 6 m | 24,000 m² |
| Base water demand | 24,000 m² × 0.6 L/m² | 14,400 L |
| Configuration check | Base demand + approved reserve versus legal payload and refill plan | Project review required |
- Route length: 4 km
- Effective spray width: 6 m
- Planning application rate: 0.6 L/m²
Illustrative planning values only. Do not use this application rate or spray width without a route trial and the approved vehicle data.
Split the route at refill points and changes in treatment
Create a route sheet with a separate segment whenever the treatment, effective width or refill access changes. Mark which areas receive spraying and which are travel only. This makes the water calculation usable for a mixed route instead of spreading one application rate over every kilometre.
The STG manual treats water loading and spray controls as specific vehicle operations. Use the proposed truck's own instructions and a documented surface trial to establish the settings and water use for this worksheet. STG Global Water Truck Operators Manual
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| Segment input | Record before sizing | Scheduling question |
|---|---|---|
| Treatment | Purpose, surface, effective treated width and passes | Which sections require a different treatment or no spraying? |
| Water use | Measured or approved rate with surface and weather conditions | What demand follows from this segment's actual treated area? |
| Refill stop | Location, access permission, connection, hours and observed filling and queue time | Can the truck reach an available refill before its planned usable water is exhausted? |
| Operating window | Spraying time, travel, traffic restrictions and crew breaks | How much of the shift remains for the next segment? |
Ask for a tank proposal tied to the route sheet
Provide each treatment segment, the application-rate basis and refill access. Require completed-mass, axle and usable-fill checks with the proposed size. Resolve stability and fill-control assumptions before approving the configuration.
Information to prepare for this review
- Area or route length treated per cycle
- Effective spray width for each mode
- Measured or approved application rate
- Refill flow, access and turnaround time
- Tank usable-volume and reserve assumptions
- Chassis gross and axle mass limits
Records to request and keep
- Route-area and operating-speed worksheet
- Documented application-rate basis
- Usable-volume and refill-cycle calculation
- Completed-vehicle mass and axle-load calculation
Common mistakes and what to check instead
- Using shell volume as usable water: Apply the approved fill, reserve and internal-volume basis.
- Assuming one application rate for all roads: Measure or approve the rate for each relevant surface and condition.
- Ignoring refill flow: Include source flow, hose connection and queue time in the cycle model.
Scope of this guide
The example method does not prescribe a universal application rate.
A qualified vehicle calculation and destination rules control final mass and capacity.
Reject the proposed tank size if gross mass, axle load, stability, fill control or route assumptions remain unresolved.
Sources and applicability
Model-specific reference for water loading, pump and spray controls. The route worksheet is a procurement aid; it does not reproduce STG settings as KEEYAK operating instructions.
Sources checked:
Controls the project-input, quotation, approval and inspection workflow described in this guide.
Provides public checklists and worksheets; the signed project documents remain controlling.
Defines the relevant product family and published configuration boundaries. Project-specific ratings require the selected OEM documents.