NFPA 20 · 2019 Edition · A.14.2.6(4)
Enter the pump's churn pressure and suction range — get the jockey and fire pump start/stop points to dial in on site.
Read churn from the certified pump curve. Read suction static from the supply.
Net shutoff (no-flow) pressure from the pump curve.
Lowest supply pressure at the pump suction.
Highest supply pressure — used for the over-pressure check.
Weakest component's rated pressure (standard = 175).
Each added pump starts 10 psi below the previous.
Top of the scale down to fire pump start.
How these are derived. The jockey pump holds the top of the band and makes up small leakage. If pressure keeps falling past the jockey's start point, the fire pump starts — that's a real demand. The last card is the safety check: churn plus the highest suction is where you risk exceeding component ratings.
Fire pump stopping. The 2019 edition generally expects the fire pump to be stopped manually. The stop pressure shown is the setpoint the annex example uses; only use automatic stop where your AHJ accepts it, and note a minimum-run timer keeps the pump running at churn past the stop pressure.
Set against calibrated gauges. Where a pressure switch's differential won't allow the exact math, set as close as the equipment permits and confirm with test gauges — uncalibrated gauges can read 15–30% off.
Reference: NFPA 20, 2019 — Annex A.14.2.6(4), "Fire Pump Settings"; jockey pump requirements §4.27; controller pressure control §10.5.2.1. This tool implements the annex method as a field aid — it does not replace the engineer of record or AHJ direction. Confirm the governing edition adopted in your jurisdiction.