Hydrant Flow Calculator Guide – Pitot Steps, Example Flows, and Field Mistakes to Avoid

Pitot Workflow (Fast + Repeatable)

1. Choose the outlet you will actually use and clear debris safely.
2. Open slowly to avoid water hammer and to stabilize flow.
3. Position pitot correctly in the stream; avoid turbulent splash zones.
4. Hold steady long enough to get a stable reading.
5. Run the calculator and write down the estimate as a planning reference.
6. Connect to demand using Fire Flow: if demand > supply, trigger a fallback plan.

Examples (How to Interpret Results)

• Example A: Hydrant flow estimate looks strong → plan primary + secondary hydrant and confirm hose package using Friction Loss.
• Example B: Flow estimate is borderline → reduce demand (tactics), improve supply (relay), or reposition.
• Example C: Flow estimate is weak/uncertain → preplan a relay/tanker fallback using Tanker Shuttle.

Common Mistakes

• Wrong outlet assumption: measuring one outlet and calculating another.
• Unstable pitot reading: turbulence/splash gives fake highs/lows.
• Ignoring redundancy: always choose primary + secondary hydrants (see Hydrant Finder).
• Over-trusting the number: treat it as an estimate and confirm with local testing data.

Field Checklist

• Outlet identified and safe to operate.
• Pitot positioned correctly and reading stabilized.
• Estimate recorded + linked to a primary/secondary hydrant plan.
• Demand check (Fire Flow) completed for training/planning context.

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