NFPA 20 acceptance: churn ≤ 140% of rated PSI; 150% flow ≥ 65% of rated PSI.
Rated Curve (Nameplate)
Auto-generated from rated values. Edit if manufacturer data differs.
Point
GPM
PSI
Acceptance Margin (NFPA)
A single 5% downward allowance is applied to the PLD Disengaged
(corrected) curve. This is based on NFPA 20's recommendation that a
pump may degrade up to 5% from its rated performance, and is also
used here to absorb human error in reading the gauges and the tolerance
of the pressure / pitot gauges themselves (assuming all gauges are
certified). A checkpoint passes if the measured value meets the rated
target outright, or falls within this 5% allowance below it.
Enter PLD Disengaged test points to generate an engineering assessment.
Manufacturer's Shop Test Curve
Chart always plots in PSI
Note: Confirm with the manufacturer that this shop test curve
is already corrected to the rated speed (typical). These values are
plotted as-entered; no RPM correction is applied on this side.
GPM
PSI
Field Test — PLD Disengaged
Net PSI = Discharge − Suction. Values are corrected back to Rated RPM via affinity law (Law 1):
Qc = Q × (Nrated/Nmeas); Hc = H × (Nrated/Nmeas)².
GPM
Suct PSI
Disch PSI
RPM
Net PSI
Corr GPM
Corr PSI
Field Test — PLD Engaged
Note: The PLD-Engaged curve should not be compared
against the rated curve or the manufacturer's shop test. It is
plotted to show where the PLD disengages and how the pump operates
with PLD active. No RPM correction is applied — PLD is meant to
operate as-is.