Tank Duration Calculator
Calculate how long a water tank will supply a fire system
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Tank Volume
Usable capacity
System Flow
Total demand
Duration
Supply time
Result
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CALCULATION
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Common Tank Sizes
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| Application | Litres | Gallons (US) |
|---|---|---|
| Small sprinkler reserve | 5,000 L | 1,320 gal |
| Typical sprinkler tank | 10,000 L | 2,640 gal |
| 30 min hydrant (750 L/min) | 22,500 L | 5,940 gal |
| 60 min hydrant (750 L/min) | 45,000 L | 11,890 gal |
| Large commercial | 90,000 L | 23,775 gal |
| Industrial / warehouse | 200,000 L | 52,835 gal |
Typical System Flows
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| System Type | L/min | GPM |
|---|---|---|
| Light hazard sprinkler (AS 2118) | 144 L/min | 38 GPM |
| Ordinary hazard sprinkler | 288 L/min | 76 GPM |
| Single hydrant (AS 2419.1) | 500 L/min | 132 GPM |
| Hydrant + internal | 750 L/min | 198 GPM |
| Two hydrants simultaneous | 1,500 L/min | 396 GPM |
| High hazard / ESFR | 2,000 L/min | 528 GPM |
AS 2419.1 Minimum Durations
| Building Class | Required Duration |
|---|---|
| Class 2-4 (Residential) | 30 minutes |
| Class 5-8 (Commercial/Industrial) | 60 minutes |
| Class 9a (Healthcare) | 60-120 minutes |
| Class 9b (Assembly) | 60 minutes |
| High-rise (>25m effective height) | 120 minutes (with top-up) |
Standards Reference
AS 2419.1 — Fire hydrant installations - System design
AS 2118.1 — Automatic fire sprinkler systems
NFPA 22 — Standard for Water Tanks for Private Fire Protection
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