Required Pump Horsepower

Introduction

Brake horsepower is a function of capacity, total head, specific gravity of the fluid, efficiency and difference between suction and discharge pressures. The primary limitations include mechanical efficiency (ME), undersized suction line, less turns in the piping and velocity.

Hydraulic/Water Horsepower:

\text{WHP} = \frac{QH\rho}{3960} \
\text{or} \
\text{WHP} = \frac{Q P_{ds}}{1715}

\text{WHP} = \frac{QH\rho}{3960} \\
\text{or} \\
\text{WHP} = \frac{Q P_{ds}}{1715}

Brake Horsepower:

\text{BHP} = \frac{QH\rho}{3960 n} \
\text{or} \
\text{BHP} = \frac{Q P_{ds}}{1715n}

\text{BHP} = \frac{QH\rho}{3960 n} \\
\text{or} \\
\text{BHP} = \frac{Q P_{ds}}{1715n}

Where:
𝑄 βˆ’ Pump Capacity (gpm)
𝐻 βˆ’ Total head (ft)
𝜌 βˆ’ Specific Gravity Relative to Water
𝑛 βˆ’ Pump Efficiency
𝑃𝑑𝑠 βˆ’ Difference between Discharge and Suction Pressure (psi)

Case Guide

Part 1: Create Case

  1. Select the Required Pump Horsepower application from the Pump Module
  2. To create a new case, click the β€œAdd Case” button
  3. Enter Case Name, Location, Date and any necessary notes.
  4. Fill out all required Parameters.
  5. Make sure the values you are inputting are in the correct units.
  6. Click the CALCULATE button to overview results.

Input Parameters

  • Calculation Method (Total Head or Differential Pressure)
  • Liquid Specific Gravity
  • Liquid Specific Gravity (Relative to Water)
  • Total Head (ft)
  • Pump Capacity (gpm)
  • Pump Efficiency (Fraction)

Part 2: Outputs/Reports

  1. If you need to modify an input parameter, click the CALCULATE button after the change.
  2. To SAVE, fill out all required case details then click the SAVE button.
  3. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
  4. To generate a REPORT, click the REPORT button.
  5. The user may export the Case/Report by clicking the Export to Excel icon.
  6. To delete a case, click the DELETE icon near the top of the widget.

Results

  • Hydraulic/Water Horsepower (hp)
  • Brake Horsepower (hp)

References

  • ASME B31.4 – 1998 Edition β€œPipeline Transportation Systems for Liquid Hydrocarbons and other Liquids”, Art. 404.1
  • API 1117 – Movement of In-Service Pipelines
  • API 5L, API 5LS and API 5LX – Specification of Pipe Grade
  • ASTM – Various – Weld Joint Factor
  • CFR Code Part 192
  • MMS Regulations
  • USDA-SCS Modified (Permissible Velocity of Water and Soil Erodibility)
  • Pipeline Rules of Thumb Handbook

Updated on December 26, 2023

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