Enter Site Demand Inputs
Example Data Table
| Scenario | Workers | Concrete (m³/day) | Dust Area (m²/day) | Base Total (L/day) | Final Total (L/day) |
|---|---|---|---|---|---|
| Mid-size structural works | 45 | 18.00 | 1,200 | 6,920 | 9,515 |
| High dust, low concrete | 30 | 6.00 | 3000 | 4,980 | 6,848 |
| Heavy pours and curing | 70 | 35.00 | 1500 | 10,865 | 15,032 |
Formula Used
- Workers demand = Workers × Water per worker × Shifts
- Mixing demand = Concrete volume (m³/day) × Mixing intensity (L/m³)
- Curing demand = Curing area (m²/day) × Curing rate (L/m²)
- Dust demand = Dust area (m²/day) × Dust rate (L/m²)
- Washdown demand = Washdowns × Water per washdown
- Base total = Sum of all components
- Peak total = Base total × Peak factor
- Final total = Peak total × (1 + Contingency% ÷ 100)
- Average flow (L/min) = Final total ÷ Operating hours ÷ 60
How to Use This Calculator
- Enter workforce, shifts, and operating hours for the day.
- Fill in concrete, curing, dust, and washdown quantities.
- Add any fixed daily process uses, like saw cooling.
- Set a peak factor to reflect concurrent bursts.
- Add a contingency to cover leaks and unknown demands.
- Click Calculate Demand to view results above.
- Download CSV or PDF to share with the site team.
Reference Article
Quantifying Demand Sources on Active Sites
Process water demand on construction sites is rarely a single number. It is the sum of workforce needs, concrete activities, curing exposure, dust control, and washdowns. This calculator breaks each source into measurable drivers so planners can update assumptions as scopes change and crews scale.
Concrete Mixing and Curing Planning
Mixing water is tied to daily concrete volume and the selected intensity in liters per cubic meter. Curing demand depends on exposed surface area and the chosen curing method, weather, and wind. Tracking both helps avoid shortages that can delay pours or compromise curing continuity.
Dust Suppression and Wash Bay Control
Dust suppression often dominates in dry seasons, especially on haul roads and stockpiles. Enter the treated area and a realistic application rate based on truck cycles or sprinkler passes. For washdowns, count events and typical water per event to represent wash bays, chute rinsing, and tool cleaning accurately.
Peak Factor and Contingency for Reliability
The peak factor accounts for simultaneous activities, refill bursts, and short-duration high flows that a simple daily total can hide. Contingency adds allowance for leaks, rework, hose losses, and unplanned tasks. Together they produce a practical planning figure for tank sizing, refill schedules, and pump selection.
Example Data for a Quick Sanity Check
Example inputs: Workers 50, water per worker 25 L/day, shifts 1, operating 10 hours; concrete 20 m³/day with 180 L/m³; curing area 300 m² at 3.5 L/m²; dust area 1500 m² at 0.8 L/m²; washdowns 10 at 60 L each; peak 1.25; contingency 10%. This yields a final demand near 8,900 L/day, about 14.8 L/min average.
FAQs
1) What does “process water” include on a construction site?
It includes water used for mixing, curing, dust suppression, washdowns, cooling, and other work activities, plus workforce-related usage that impacts daily supply planning.
2) How should I choose the water per worker value?
Use site records when available. Otherwise, select a value that reflects climate, shift length, and welfare facilities. Hotter conditions and longer shifts typically require higher per-worker volumes.
3) Why is a peak factor needed if I already have daily totals?
Daily totals can hide short bursts when multiple tasks run together. The peak factor helps size pumps and storage so supply can meet simultaneous high-demand periods without pressure drops.
4) What is a reasonable contingency percentage?
Many projects use 5–15% depending on uncertainty and control measures. Higher contingency suits early planning, remote sites, or variable scopes. Lower values fit tightly managed, measured operations.
5) Does this calculator account for recycled or reclaimed water?
Not directly. If you reuse water, subtract the expected reclaimed volume from “Other process uses” or reduce the relevant rates, then validate with on-site measurements and quality limits.
6) How can I estimate washdown water per event?
Multiply hose flow rate by minutes used, or measure using a container and stopwatch. Use typical events, not best-case values, and include wash bay rinse-downs and tool cleaning routines.
7) Which result should I use for tank sizing and refill frequency?
Use the final total (after peak and contingency) for storage planning, and the average L/min for pump selection during operating hours. Adjust if you plan refills only at specific times.