How is pump brake horsepower (BHP) calculated?

Brake Horsepower (BHP) is calculated by dividing the Hydraulic (Water) Horsepower by the pump efficiency. Formula: BHP = (Q × H × SG) / (3960 × η), where Q is flow in GPM, H is head in feet, SG is specific gravity, and η is efficiency.

What is the difference between NPSHa and NPSHr?

NPSHa (Available) is the absolute pressure at the pump suction minus vapor pressure, determined by the system design. NPSHr (Required) is the minimum pressure required by the pump to prevent cavitation, determined by the manufacturer. For safe operation, NPSHa must exceed NPSHr.

How do you calculate pump total dynamic head (TDH)?

Total Dynamic Head (TDH) is the total equivalent height that a fluid is to be pumped, taking into account friction losses in the pipe. TDH = Static Head + Friction Head + Pressure Head.

Pump Sizing & System Head Calculator | Pipe Friction, TDH & NPSH

Calculation Mode:

Simple Pipeline
Know: Flow, pipe specs, elevations

System Analysis
Have: Pressures & head losses

Quick Estimate
Fast preliminary sizing

Analysis Capabilities

System Modeling:
Account for Pipe Length, Fittings (Elbows, Tees, Valves), Elevation Changes (Static Head), and Tank Pressures.

Pressure & Loss:
Total Dynamic Head (TDH), Darcy-Weisbach Friction Loss, Pressure Drop analysis, and System Head Analysis.

Performance Outputs:
Brake Horsepower (BHP), Hydraulic Power (WHP), NPSHa (Available), NPSHr (Required), Motor Sizing (API 610/NEMA).

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📘 Mode Selection Guide

Choose the right mode for your situation:

🔧 Simple Pipeline Mode

Starting from scratch with basic pipeline info
Need automatic friction loss calculations
Calculates: Friction, head, motor size, NPSH

📊 System Analysis Mode

You have measured system pressures
Head losses already calculated
Replacing existing pump

⚡ Quick Estimate Mode

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Preliminary feasibility study
Fast estimate with minimal inputs

Core Formulas

Water Horsepower:

                                WHP = (Q × H × SG) / 3960
                            

Brake Horsepower:

                                BHP = WHP / ηpump
                            

Required Motor HP:

                                Motor HP = (BHP × SF) / (ηmotor × 1.15)
                            

Specific Speed:

                                Ns = (N × √Q) / H0.75
                            

Standards Reference

API 610: Centrifugal pumps for petroleum
API 674: Positive displacement pumps
ANSI/HI 9.6.1-2017: NPSH margin
NEMA MG-1: Motor standards
Darcy-Weisbach: Friction loss equation

Pump Sizing Calculator

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Pump Sizing Calculator

Analysis Capabilities

📚 Learn the Theory

📘 Mode Selection Guide

Core Formulas

Results

Standards Reference

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