| Scenario | Unit | Stream 1 (flow × min) | Stream 2 (flow × min) | Stream 3 (flow × min) | Proportioning | Safety | Reserve | Total Concentrate (rounded) |
|---|---|---|---|---|---|---|---|---|
| Fuel area | L/min | 1,200 × 20 | 600 × 15 | 0 × 0 | 3% | 10% | 100 L | (1,200×20 + 600×15)×0.03×1.10 + 100 ≈ 1,177 L |
| Warehouse | GPM | 250 × 30 | 150 × 20 | 100 × 15 | 6% | 15% | 0 L | Converted to L/min, then sized from totals. |
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Convert flow to L/min when needed
Flow(L/min) = Flow(GPM) × 3.78541 -
Solution volume per stream
Solution(L) = Flow(L/min) × Duration(min) -
Total solution volume
TotalSolution(L) = Σ SolutionStream(L) + ExtraAllowance(L) -
Concentrate required
Concentrate(L) = TotalSolution(L) × (Percent/100) -
Storage with safety and reserve
TotalConcentrate(L) = Concentrate(L) × (1 + Safety%/100) + Reserve(L) -
Optional mass estimate
Mass(kg) = TotalConcentrate(L) × Density(kg/L)
- Select the same flow unit used on your drawings or pump data.
- Enter each discharge stream flow and its expected duration.
- Add an extra allowance for flushing, hose streams, or startup.
- Set the proportioning percentage based on the foam type.
- Apply a safety factor and optional reserve for contingencies.
- Press Calculate to show results above the form instantly.
- Download CSV or PDF to attach to submittals and logs.
Define the discharge demand clearly
Start with credible discharge scenarios from drawings, hazard analysis, and equipment data. Separate fixed monitors, hose lines, and deluge zones into streams so the calculation reflects real operations. Use the same flow unit used by pumps and test reports, and confirm whether values represent rated or measured flow. When the scenario is uncertain, use conservative durations and document the assumption for review.
Aggregate streams into total foam solution volume
The calculator converts each stream into solution volume by multiplying flow by duration. Summing the streams provides the total solution demand for the event, then an extra allowance can be added for flushing lines, startup delays, and manual application. This approach keeps the math transparent and lets reviewers see how each stream contributes to the final demand.
Apply proportioning percentage correctly
Foam concentrate requirement is the total solution volume multiplied by the selected proportioning percentage. Common proportioning rates include 1%, 3%, and 6%, but the correct value depends on the foam type and the fuel hazard. Always size storage using the percentage required by the foam listing, manufacturer data, and the project specification.
Account for safety, reserve, and practical rounding
A safety factor helps cover testing losses, minor leaks, and uncertainty in flow and duration. Reserve concentrate adds a fixed buffer for maintenance, refill delays, or phased construction exposure. Finally, rounding aligns the storage volume to available tank sizes or tote quantities so procurement and logistics are simpler. Recording the rounding step prevents confusion between calculated and purchased volumes.
Use outputs for procurement and documentation
The results provide solution volume, concentrate volume in liters and gallons, and an optional mass estimate using density. Mass helps with lifting plans, transport limits, and secondary containment considerations. Export the CSV for submittals, commissioning checklists, and change-control records. The PDF record supports approvals during inspections and helps maintain consistent sizing across teams for audit trails and turnover.
1) What does “foam solution” mean in this calculator?
Foam solution is the mixed discharge of water plus concentrate. The calculator totals solution volume from all streams, then computes concentrate as a percentage of that solution.
2) When should I use GPM versus L/min?
Use the unit that matches your pump curves and test documents. Selecting GPM automatically converts to liters per minute so all volumes are computed consistently.
3) Why add an extra solution allowance?
Extra allowance covers line filling, flushing, startup stabilization, and manual hose application that may not be captured in fixed stream flows and durations.
4) How do I choose a safety factor?
Select a factor that reflects site uncertainty and testing needs. Many projects use 5–20%, but always follow project requirements and risk-based engineering judgment.
5) What is the purpose of a reserve volume?
Reserve is a fixed buffer for maintenance drawdown, refill delays, or staged construction exposure. It is added after applying the safety factor.
6) Does density change the volume result?
No. Density only estimates mass for transport and lifting planning. The required concentrate volume is based on solution demand, proportioning percentage, safety, and reserve.