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NPSHA Calculator

Net Positive Suction Head Available at the pump suction — the margin that protects a pump from cavitation.

ModuleNPSHA CalculationMethodEnergy BalanceVersion1.0.0
1

Input Parameters

kg/m³
m
kPa(abs)
kPa(abs)
m
m
m

Estimate Vapor Pressure from Temperature

°C

Estimated P_v ≈ 2.330 kPa(abs)

2

Results

Ready to calculate NPSHA?

Enter suction parameters above and click Calculate NPSHA to evaluate pump cavitation margins.

4

Reference Codes & Standards

ANSI/HI 9.6.1-2024Governing Code

Rotodynamic Pumps — Guideline for NPSH Margin

Scope:Recommended NPSH margin ratios between NPSHA and NPSHR (NPSH3).
ANSI/HI 14.6-2016 / ISO 9906:2012Governing Code

Rotodynamic Pumps — Hydraulic Performance Acceptance Tests

Scope:Defines NPSHR as the 3% head-drop point (NPSH3) used for the pump requirement.
API 610 12th Ed. / ISO 13709:2009Governing Code

Centrifugal Pumps for Petroleum, Petrochemical & Natural Gas

Scope:Minimum NPSH margin requirements for process pump selection.
ANSI/HI 9.6.3-2024Governing Code

Rotodynamic Pumps — Guideline for Allowable Operating Region

Scope:Suction conditions & operating-region limits affecting NPSH.
Literature & Further Reading
  • [1]Karassik et al., Pump Handbook — NPSH fundamentals & suction design.
  • [2]Cameron Hydraulic Data (Ingersoll-Rand) — vapor pressure & head loss data.
  • [3]Perry's Chemical Engineers' Handbook — Antoine constants for vapor-pressure estimation.
  • [4]NIST Chemistry WebBook — reference vapor-pressure data.
  • [5]ANSI/HI standards — NPSH terminology and margin practice.