Document / Project Reference
Pump Sizing
Centrifugal · Reciprocating · Screw  —  Hydraulic Institute · API 610 · ISO 13709
Screening-level calculation — not a code-compliant design document
Company
Project
Doc. No.
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Equip. / Tag
Date
INPUT PARAMETERS
Parameter Value Unit Notes
  |  Hazem ElMancy — Pump Sizing
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EQUIPMENT

Pump Sizing

Centrifugal, reciprocating & screw pumps — suction head, NPSH, discharge head, differential pressure, hydraulic power, shaft power, shut-off pressure, specific speed and impeller diameter.

Hydraulic Institute API 610 / ISO 13709 GPSA §13 Perry's §10
All Calculators
Input Parameters
Fluid & Flow
Required
Documentation basis only; enter density/viscosity at operating temperature.
Use for vapor-pressure basis / NPSHa screening.
Must be > 0
Must be > 0
Required and must be ≥ 0
Enter at maximum pumping temperature for NPSHa.
Must be > 0
Continuous flow recycle
Pump Configuration
Above grade
Required for centrifugal specific speed and reciprocating acceleration-head checks.
Centrifugal only: 1 stage or multi-stage high-head service.
Centrifugal only. Used for workbook-style required NPSH screening.
Workbook cell F38. Final value by project/vendor criteria.
Blank = centrifugal screening estimate; manual value preferred for EPC checks.
Suction Conditions
Must be > 0
Required
Above grade
Use Liquid Hydraulics calculator
Discharge Conditions
Must be > 0
Required
Above grade
HEX, filter, flow element, etc.
Shut-off Pressure
Absolute pressure basis; do not enter barg unless converted.
Above grade
Centrifugal screening default only. Vendor curve required for final shut-off pressure.

Enter parameters and click Calculate.

Methodology

  • Suction head: P_suc = P_vessel + ρg(L_level − CL)/1000 − ΔP_line [kPaa]
  • NPSHa calculated: NPSHa = (P_suc,abs − P_vap)/(ρg). Vendor NPSHr is not calculated.
  • Discharge head: P_dis = P_vessel + ρg(L_level − CL)/1000 + ΔP_line + ΔP_CV + ΔP_eq [kPaa]
  • Differential: ΔP = P_dis − P_suc; ΔH = ΔP × 1000 / (ρg)
  • Hydraulic power: P_hyd = ΔP [kPa] × Q [m³/s] [kW]
  • Pump efficiency: user-entered efficiency if provided; otherwise a screening estimate is used for power only.
  • Reciprocating efficiency: 90% (fixed); Screw: 85% (fixed)
  • Centrifugal shut-off pressure: P_so = P_suc,max + selected shut-off/rated head ratio × ΔP_design. Vendor curve required for final value.
  • Specific speed: N_s = N × √Q [m³/s] / H_stage³⁄&sup4; [SI]
  • Impeller diameter: D = (60/πN) × √(2g × H_stage / ψ) where ψ = 0.75
  • Reciprocating acceleration head: Ha = L × v × N / (C × k × g)

Pump Type Classification (Specific Speed, SI)

  • N_s < 15: Radial Flow (high head, low flow)
  • 15 ≤ N_s < 70: Mixed Flow
  • N_s ≥ 70: Axial Flow (low head, high flow)

Assumptions

  • Single-phase liquid flow; isothermal; ρ and μ constant
  • All pressures are absolute (kPaa / psia) except stated differentials
  • Centrifugal efficiency is estimated from flow only — validate against vendor curves
  • Default shut-off ratio 1.25 is a screening assumption for centrifugal pumps only; verify against vendor curve, especially for multi-stage pumps.
  • NPSH margin allowance is a screening input; final NPSH margin shall follow project/company criteria and vendor NPSHr curve.
  • Screening-level result — subject to project / company criteria

References

  • Hydraulic Institute Standards for Centrifugal, Rotary and Reciprocating Pumps
  • API 610 / ISO 13709: Centrifugal Pumps for Petroleum, Petrochemical and Natural Gas Industries
  • GPSA Engineering Data Book, Section 13 (Pumps / reciprocating pump acceleration-head screening)
  • Crane TP-410 and API RP 14E are referenced indirectly for suction/discharge line loss and velocity-limit inputs developed in companion hydraulics calculations.
  • Perry's Chemical Engineers' Handbook, Section 10