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NFPA 20
Validated against the standard.
PDF export
Pro-only. Generate professional reports.
$2.99 Pro
Lifetime unlock. No subscriptions.
How it works
Enter your values
Type in your inputs — the app fills code tables and constants for you, so there's nothing to look up.
Get a code-checked result
Instant answer with a clear PASS / FAIL and the exact NFPA 20 reference behind every number.
Save & export
Keep a history of calculations and export a clean PDF report to share or attach to a permit (Pro).
What this calculator does
A fire pump is defined by three points on its curve. This app checks a pump against the NFPA 20 performance requirements and plots the curve, so you can confirm a pump meets the system demand with margin.
The NFPA 20 performance points
- Churn (no flow) — shutoff pressure not more than 140% of rated pressure.
- Rated point — 100% rated flow at 100% rated pressure.
- Overload — at 150% of rated flow, the pump must still deliver at least 65% of rated pressure.
Worked example
A pump rated 1,000 GPM at 100 psi must hold churn ≤ 140 psi, deliver 100 psi at 1,000 GPM, and still produce ≥ 65 psi at 1,500 GPM. The app checks each point against the system demand.
Related calculators
Find the demand with the sprinkler hydraulic calculator and the source with the water supply calculator.
Fire pump FAQ
What are the three NFPA 20 points?
Churn (shutoff) at no more than 140% of rated pressure, the rated point at 100%/100%, and the 150% flow point where the pump must hold at least 65% of rated pressure.
Why does the 150% point matter?
It guarantees the pump can supply well above its rated flow during a large fire without its pressure collapsing, which is the safety margin NFPA 20 requires.
Does it plot the curve?
Yes. It builds the three-point curve so you can overlay system demand and confirm the pump is adequate.
Does it work offline?
Yes, it runs 100% offline with no account. Free with rewarded ads; a one-time $2.99 Pro unlock adds PDF export and saved history.
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